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Precipitation radar as a source of hydrometeorological data Bonser, J. D. 1982

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PRECIPITATION  RADAR  AS A SOURCE OF H Y D R O M E T E O R O L O G I C A L  by  J.D. B.A.Sc,  University  A THESIS THE  BONSER  of B r i t i s h  SUBMITTED IN PARTIAL R E Q U I R E M E N T S FOR MASTER  Columbia,  FULFILMENT  T H E D E G R E E OF  OF A P P L I E D  SCIENCE  in THE  FACULTY  Department  We  accept to  THE  OF GRADUATE Of C i v i l  this  UNIVERSITY  OF  August  ©  Engineering  thesis  the required  STUDIES  as conforming standard  BRITISH  COLUMBIA  1982  J.D. B o n s e r ,  1982  1980  OF  DATA  In  presenting  this  thesis  in  partial  fulfilment  of  requirements f o r an advanced degree at the U n i v e r s i t y of Columbia,  I  available  for  permission  agree  for  purposes may or  her  that  the  Library  shall  reference  and  study.  I  extensive  p u b l i c a t i o n of t h i s t h e s i s allowed without my  Department of  written  Civil  Date:  20 August  1982  It for  is  it  freely  agree  Department or  understood  financial  permission.  Engineering  The U n i v e r s i t y of B r i t i s h 2075 Wesbrook Place Vancouver, Canada V6T 1W5  further  British  that  copying of t h i s t h e s i s f o r s c h o l a r l y  be granted by the Head of my  representatives.  make  the  Columbia  gain  that  by  his  copying or  shall  not  be  i i  ABSTRACT  The  application  measurements thesis.  to  The  Archive for  of  for  storm  Atmospheric and  radar  data  five  those  interactive  and  limitations case  the data  to  data  the  the  are  archive  described,  Storm  i n Vancouver and  is  temporal drawn  system  hydrologists.  is  displayed  are  to  Canadian  in this  data  An  presented  and  image  sequences  rainfall and  the  and  data  benefits An  Management  given,  the  results.  improvements make  radar  a  given.  urban  Model  to  data  to  conclusions  r e s o l u t i o n requirements  from for  the  studied.  Water  tool.  Abbotsford  is  radar-deirived are  detailed  i n v e s t i g a t e d , and  system  source  recommendations  the  engineering  values  models  using  spatial sources  radar  raingauge  in  a  in  inherent  are  seen  this  catchment  with  to  of  radar  from  Errors  by  this  current  measurement  SCEPTRE  display  and  followed  processing  A p p l i c a t i o n s of  study  concludes and  during  runoff  phenomena  obtained  Service.  patterns  engineering  a  was  image  to  rainfall  events  precipitation  investigated in  quantitative  operational  colour  discussed.  regarding  the  point  are  is  introduced,  a  with  precipitation  simulate  are  as  introduced  hydrology  precipitation  Environment  comparison  runoff  of  techniques  explanation  radar-derived  engineering  nature  measurement  of  of  The  thesis  the  SCEPTRE  more  useful  iii  TABLE OF CONTENTS  ABSTRACT  i i  TABLE OF CONTENTS  i i i  ' L I S T OF TABLES  v  L I S T OF FIGURES  vi  ACKNOWLEDGEMENT  ix  1 INTRODUCTION  1  2 PRECIPITATION  3  2.1  Introduction  2.2 The S t r u c t u r e  3 Of P r e c i p i t a t i o n  Systems  3  2.3 The M e a s u r e m e n t Of P r e c i p i t a t i o n  5  2.4 H y d r o l o g i c  6  Implications  3 RADAR MEASUREMENT OF P R E C I P I T A T I O N 3.1  8  Introduction  3.2 P r i n c i p l e s  8  Of R a d a r  8  3.3 The R a d a r E q u a t i o n  11  3.4 The Z-R R e l a t i o n  15  3.5 L i m i t a t i o n s To R a d a r M e a s u r e m e n t Of Precipitation  17  3.6 D i g i t a l T e c h n i q u e s F o r Q u a n t i t a t i v e Measurement  Rainfall  3.7 The SCEPTRE R a d a r 4 RADAR-DERIVED P R E C I P I T A T I O N MEASUREMENTS OVER THE VANCOUVER AREA 4.1  Introduction  25 27 39 39  4.2 The A b b o t s f o r d SCEPTRE R a d a r I n s t a l l a t i o n  39  4.3 D a t a O b t a i n e d From The AES A r c h i v e  40  4.4 E r r o r s I n CAPPI D a t a  44  4.5 C o m p a r i s o n W i t h R a i n Guage R e c o r d s  51  4.6 I n t e r a c t i v e Image D i s p l a y S y s t e m  62  4.7 P a t t e r n s Of P r e c i p i t a t i o n O v e r The V a n c o u v e r Area  74  5 HYDROLOGICAL APPLICATIONS OF SCEPTRE RADAR DATA  85  5.1 I n t r o d u c t i o n  85  5.2 G e n e r a l A p p l i c a t i o n s  85  5.3 A p p l i c a t i o n To E n g i n e e r i n g H y d r o l o g y - R u n o f f Modelling  90  5.4 E n g i n e e r i n g Use Of R a d a r - D e r i v e d D a t a : Urban Runoff Case Study  93  Precipitation  5.5 R e c o m m e n d a t i o n s F o r I m p r o v e m e n t s To The SCEPTRE R a d a r And D a t a A r c h i v e And R e t r i e v a l 101 6 CONCLUSIONS  105  REFERENCES AND BIBLIOGRAPHY  107  APPENDIX A - SCEPTRE R a d a r M e a s u r e m e n t A l t i t u d e s C o r r e c t e d f o r E a r t h C u r v a t u r e and S t a n d a r d Beam R e f r a c t i o n  113  APPENDIX B - Summary o f AES D a i l y R a i n g a u g e and Gauge/Radar Measurements  118  Locations  APPENDIX C - F l o w c h a r t S h o w i n g CAPPI Image G r i d E x t r a c t i o n , E r r o r C o r r e c t i o n , Data T r a n s f e r , a n d Image G e n e r a t i o n P r o c e s s e s 121  V  LIST OF TABLES  3.1  F r e q u e n c i e s used i n weather r a d a r systems  16  3.2  Raytheon WSR-807 r a d a r s p e c i f i c a t i o n s  29  3.3  SCEPTRE C scan range and s e n s i t i v i t y o p t i o n s  35  3.4 Normal CAPPI c o n s t r u c t i o n t a b l e : range gate  settings  and c o r r e s p o n d i n g e l e v a t i o n a n g l e s  36  4.1  Storm r e c o r d s r e c e i v e d from AES  42  4.2  2 km CAPPI c o n s t r u c t i o n t a b l e  43  4.3  SCEPTRE DVIP s i g n a l - r a i n f a l l  4.4  G/R  intensity calibration  r a t i o s f o r 5 days of r a i n f a l l d a t a  ..43 59  LIST OF FIGURES  3.1 Radar d e t e c t i o n o f p r e c i p i t a t i o n  9  3.2 T y p i c a l antenna beam p a t t e r n  10  3.5 Beam volume  13  3.4 E f f e c t of t h e c u r v a t u r e of t h e e a r t h  18  3.5 A t t e n u a t i o n of t h e r a d a r beam by i n t e r v e n i n g precipitation  18  3.6 L i m i t a t i o n of r e s o l u t i o n due t o p u l s e l e n g t h  21  3.7 L i m i t a t i o n of r e s o l u t i o n due t o beam w i d t h  21  3.8 O c c u l t a t i o n of t h e r a d a r beam  ...22  3.9 Cone o f s i l e n c e  23  3.10 S u p e r r e f r a c t i o n of t h e r a d a r beam  24  3.11 CAPPI C o n s t r u c t i o n  26  3.12 AES weather r a d a r i n s t a l l a t i o n s i n Canada  27  3.13 SCEPTRE r a d a r schematic  28  3.14 Radar tower and c o n t r o l b u i l d i n g a t t h e A b b o t s f o r d SCEPTRE s i t e  30  3.15 T r a n s m i t t e r , r e c e i v e r , and antenna c o n t r o l equipment .31 3.16 3.66 m d i a m e t e r p a r a b o l i c antenna and p e d a s t a l mount .32 3.17 PPI i n d i c a t o r and c o n t r o l c o n s o l e  33  3.18 PDP-11/35 minicomputer and system c o n t r o l equipment ..34 3.19 O s c i l l o s c o p e showing a s i n g l e A scan and the PPI display  35  3.20 P r o c e s s i n g c y c l e t i m i n g c h a r t  36  3.21 An example of a CAPPI f a c s i m i l e from t h e A b b o t s f o r d SCEPTRE i n s t a l l a t i o n  37  4.1 L o c a t i o n o f t h e A b b o t s f o r d SCEPTRE r a d a r w i t h cone of s i l e n c e and 20 km range r i n g s marked  40  4.2 Coverage of 2 km CAPPI  41  4.3 U n c o r r e c t e d c u m u l a t i v e December 1980 storm 4.4 C o n v o l u t i o n  r a i n f a l l pattern f o r the  45  p a t t e r n f o r image c o r r e c t i o n  4.5 C o r r e c t e d c u m u l a t i v e 1980 storm  47  r a i n f a l l p a t t e r n f o r t h e December  4.6 Comparison of c o r r e c t e d and u n c o r r e c t e d p r o f i l e s f o r December 1980 storm  cumulative  48 49  4.7 L o c a t i o n s of s t a t i o n a r y echoes  50  4.8 L o c a t i o n of AES raingauge s t a t i o n s w i t h d a i l y r e c o r d s  .52  4.9 R a d a r / r a i n g a u g e r e g r e s s i o n r e l a t i o n s h i p f o r 20 December 1980  53  4.10 Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p f o r 21 December 1980  54  4.11 Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p f o r 12 F e b r u a r y 1981  55  4.12 Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p f o r 13 F e b r u a r y 1981  56  4.13 Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p f o r 14 F e b r u a r y 1981  57  4.14 H y e t a l s u r f a c e r e p r e s e n t a t i o n s of radar and raingauge data f o r 20 December 1980 58 4.15 G/R r a t i o as a f u n c t i o n of d i s t a n c e from t h e radar 4.16 C h a r a c t e r patterns  m a t r i x r e p r e s e n t a t i o n of the r a i n f a l l  4.17 I s o h y e t a l r e p r e s e n t a t i o n of the r a i n f a l l p a t t e r n s 4.18  ...60 64 ....65  H y e t a l s u r f a c e r e p r e s e n t a t i o n of t h e r a i n f a l l patterns  67  4.19 C o l o u r r e p r e s e n t a t i o n of t h e r a i n f a l l p a t t e r n s 4.20 IBM P e r s o n a l Computer used f o r d i s p l a y i n g t h e CAPPI images  68 71  4.21 MTS h o s t - IBM PC d a t a t r a n s f e r l i n k  72  4.22 C o l o u r m o n i t o r d i s p l a y showing range r i n g s and o v e r l a y map  73  4.23 R a i n f a l l i n t e n s i t y p a t t e r n - 1044 GMT 22 December 1980  75  vi i i  4.24 R a i n f a l l i n t e n s i t y p a t t e r n - 1054 GMT 22 December 1980  75  4.25 R a i n f a l l i n t e n s i t y p a t t e r n - 1104 GMT 22 December 1980  76  4.26 R a i n f a l l i n t e n s i t y p a t t e r n - 1114 GMT 22 December , 1980  76  4.27 R a i n f a l l i n t e n s i t y p a t t e r n - 1124 GMT 22 December 1980  77  4.28 R a i n f a l l i n t e n s i t y p a t t e r n - 1134 GMT 22 December 1980  77  4.29 R a i n f a l l i n t e n s i t y p a t t e r n - 1144 GMT 22 December 1980  78  4.30 R a i n f a l l i n t e n s i t y p a t t e r n - 1154 GMT 22 December 1980  78  4.31 R a i n f a l l i n t e n s i t y p a t t e r n - 1204 GMT 22 December 1980  79  4.32 R a i n f a l l i n t e n s i t y p a t t e r n - 1214 GMT 22 December 1980 v  79  4.33 R a i n f a l l i n t e n s i t y p a t t e r n - 1224 GMT 22 December 1980  80  4.34 R a i n f a l l i n t e n s i t y p a t t e r n - 1234 GMT 22 December 1980  80  4.35 R a i n f a l l i n t e n s i t y p a t t e r n - 1244 GMT 22 December 1980  81  4.36 R a i n f a l l i n t e n s i t y p a t t e r n - 1254 GMT 22 December 1980  81  4.37 R a i n f a l l i n t e n s i t y p a t t e r n - 1304 GMT 22 December 1980  82  5.1 Map of F r a s e r v i e w  95  catchment  5.2 SWMM o u t l e t hydrograph f o r t h e F r a s e r v i e w December 1980 storm  catchment,  96  5.3 Comparison o f SWMM o u t l e t hydrographs f o r normal and r e v e r s e d storm d i r e c t i o n s  97  5.4 Comparison o f SWMM hydrographs from t e n minute and e q u i v a l e n t h o u r l y gauge data  98  radar  5.5 S p a t i a l / t e m p o r a l r e s o l u t i o n r e q u i r e m e n t s o f r a i n f a l l data - storm v e l o c i t y 60 kmh  100  ix  ACKNOWLEDGEMENTS'  I would l i k e t o appreciation his  advice  preparation  and and  take  this  opportunity  thanks t o my a d v i s o r Dr. guidance  during  the  to  research  Department,  the  Ken  R i c h a r d Brun of Anderson  of t h e  of T r a n s p o r t , and Rowan B i r c h and Wayne Reese of t h e  C i t y of Vancouver a l s o deserve my b e h a l f . Computing  In a d d i t i o n , I Centre  thanks f o r a l l t h e i r e f f o r t s on  would  like  the N a t i o n a l Research scholarship  t o commend  t h e UBC  f o r t h e e x c e l l e n t s e r v i c e i t has p r o v i d e d  d u r i n g t h e c o u r s e of my r e s e a r c h .  The f i n a n c i a l a s s i s t a n c e of  C o u n c i l of  Canada  i n t h e form  of  a  and r e s e a r c h f u n d i n g i s g r a t e f u l l y acknowledged.  F i n a l l y , I would l i k e t o e x p r e s s my friends  throughout  and  of t h i s t h e s i s , and t o Dr. D e n i s R u s s e l l f o r h i s  the UBC C i v i l E n g i n e e r i n g  many  my  B i l l Caselton f o r  v a l u a b l e s u g g e s t i o n s and review of t h i s work.  Ministry  express  whose  support,  sincere  appreciation to  encouragement,  and  t h e l a s t two y e a r s have made my graduate  p l e a s a n t and memorable e x p e r i e n c e .  kindness  studies  a  1  CHAPTER I  INTRODUCTION Water resources management i n v o l v e s the p l a n n i n g , d e s i g n , •  c o n s t r u c t i o n , and o p e r a t i o n of water c o n t r o l  facilities.  In  every phase of t h i s management p r o c e s s , d e c i s i o n s are r e q u i r e d which demand that the engineer  use h i s knowledge and  judgement to achieve c l o s e to optimal r e s u l t s . complexity of  procedures,  The  has  necessitated  more  complex  many  analysis  and  instances  runoff  precipitation  this  information  and  streamflow  records  in  lieu  data with s u f f i c i e n t  s p a t i a l and  r e a l i s t i c modelling  of  However,  and flow  accurate  is  to  and  model  thereby  use  data.  This  precipitation  r e s o l u t i o n to  allow  practices.  p r e c i p i t a t i o n measurement system  and  higher temporal  and  and  a data  truly  first  glance,  operational  archive  s p a t i a l r e s o l u t i o n than  networks would, at  significant  approach  temporal  of  raingauge  data.  not a v a i l a b l e ,  the  demands  availability  offer  recent  One  is  process  approach  much  of  design of water resources p r o j e c t s i s  hydrometeorological  The  analysis  data.  a l t e r n a t i v e methods must be used. the  level  which i n t u r n have r e q u i r e d g r e a t e r q u a n t i t i e s  i d e a l l y based on long records of hydrometric in  The i n c r e a s i n g  of water resource systems a c h i e v i n g t h i s h i g h  performance  reliable  intuitive  be  offering  conventional expected  to  r e l a t i v e l y easy to achieve b e n e f i t s i n  2  many a r e a s of water r e s o u r c e s a n a l y s i s . investigation  these  However,  the  high  closer  advantages a r e accompanied by sources of  e r r o r and problems of r e s o l u t i o n which when  at  resolution  data  only  become  i s scrutinized.  problems of d e a l i n g w i t h t h e l a r g e q u a n t i t i e s  apparent Additional  of  information  generated are a l s o r a i s e d . The  original  application spatially  of and  intent  the  was t o f o c u s on the a d a p t a t i o n and  new  data  temporally  source  in  conjunction  s e n s i t i v e water r e s o u r c e s  W h i l e t h i s o b j e c t i v e was reached t o a  degree,  different  system  nature  of  the  radar  n e c e s s i t a t e d f a r g r e a t e r e f f o r t overcoming and  researching  ways  to  access  r e s u l t i n g e x p l a n a t i o n of t h e  radar  and  the of  the  view  models. radically  measurement  data  the  measurement  with  defects  data.  The  process  and  d a t a p r e s e n t a t i o n i n t h e r e s e a r c h a r o s e , not from l o s i n g s i g h t of  the  potential  data a p p l i c a t i o n s , but by t h e n e c e s s i t y of  a d d r e s s i n g a l l data r e l a t e d problems t o foundation  promote  f o r i t s subsequent e x p l o i t a t i o n .  a  realistic  3  CHAPTER I I  PRECIPITATION 2.1 I n t r o d u c t i o n  Precipitation  data  i s one of the key i n g r e d i e n t s i n any  s i m u l a t i o n of urban r u n o f f . precipitation design systems  mechanisms  viewpoint are  accurate  not  i s highly  point  are understood,  precipitation  still  precipitation  A l t h o u g h most of the  variable  measurement  to  large  precipitation  is  measurement,  in  is  to  studied,  In  space  difficult  this  and  remote s e n s i n g by s a t e l l i t e , a r e 2.2 The S t r u c t u r e of P r e c i p i t a t i o n  resources  defined.  both  to  chapter  current  i n c l u d i n g raingauge networks,  Precipitation  water  depth accumulated  error.  of  from an e n g i n e e r i n g  satisfactorally  e s t i m a t i o n of p r e c i p i t a t i o n subject  inputs  physics  Because and  time,  achieve  over an a r e a the  and is  n a t u r e of  techniques  for  r a d a r systems,  and  reviewed. Systems  i s a f a m i l i a r n a t u r a l phenomenon.  Although  most p e o p l e have some awareness of the v a r i a b i l i t y of r a i n f a l l i n b o t h space and t i m e , they would have quantifying  their  Meteorologists  have  or  difficulty  in  i n t u i t i v e i m p r e s s i o n of t h i s v a r i a b i l i t y . adopted  scheme and view p r e c i p i t a t i o n 1. Synoptic  great  macroscale.  a  qualitative  classification  phenomena a t t h r e e s c a l e s : Storms which a r e d i s c e r n a b l e on  4  weather  satellite  photographs,  associated  with  low  p r e s s u r e and f r o n t a l systems, a r e s y n o p t i c s c a l e e v e n t s . They a r e g e n e r a l l y on t h e o r d e r o f hundreds o f k i l o m e t r e s in  size.  I n t h e Vancouver a r e a they a r e u s u a l l y i n t h e  form of c y c l o n i c systems moving e a s t w a r d o f f t h e  Pacific  Ocean. 2. M e s o s c a l e .  Within  the  band  of  precipitation  s y n o p t i c system i s a "pebbly s t r u c t u r e " precipitation. in  extent  band  of  of  patterns  and  sixty  km a p a r t , and move i n s t e p as t h e  precipitation  or  of  These a r e a s a r e t y p i c a l l y t e n t o f i f t y km  sweeps  over  the  Thuderstorms a r e a n o t h e r example of mesoscale 3. Convective  from t h e  microscale.  convective c e l l s .  Within  mesoscale  earth.  systems. events are  These c e l l s , which a r e r e s p o n s i b l e f o r  i n t e n s e b u r s t s of r a i n f a l l  over  short  time  intervals,  range from two t o s e v e r a l k i l o m e t r e s a c r o s s , and l a s t f o r up  t o an hour.  The a r e g e n e r a t e d by a l o c a l i n s t a b i l i t y  i n t h e atmosphere, grow r a p i d l y , and o f t e n c o n t a i n s t r o n g u p d r a f t s and d o w n d r a f t s . Precipitation  i s often c l a s s i f i e d  into  three  principal  categories: cyclonic,  o r o g r a p h i c , and c o n v e c t i v e , depending on  the  mechanism  dominant  lift  causing  C y c l o n i c r a i n f a l l a r i s e s when m o i s t system air  the  airmasses  precipitation. in a  frontal  r i s e due t o t h e h o r i z o n t a l convergence of envelopes of having  different  temperatures.  In  orographic  p r e c i p i t a t i o n , u p l i f t due t o t h e passage of t h e a i r m a s s over a topographic  feature  causes  the p r e c i p i t a t i o n .  Convective  5  rainfall  occurs  airmasses  when  generates  differential a  local  heating  instability.  of  adjacent  I n the Vancouver  a r e a , e x t r a - t r o p i c a l c y c l o n i c systems a r e the p r i n c i p a l of p r e c i p i t a t i o n , yield  local  with  orographic  variations  in  the  effects  source  superimposed  to  amount of r a i n f a l l r e c e i v e d  [Hay 7 3 ] . 2.3 The Measurement of P r e c i p i t a t i o n  The s u c c e s s f u l d e s i g n and o p e r a t i o n  of  water  p r o j e c t s depends on t h e c o l l e c t i o n and a c c u r a t e of b a s i c h y d r o m e t e o r o l o g i c a l d a t a . play the  an  interpretation  P r e c i p i t a t i o n measurements  i m p o r t a n t r o l e i n many water r e s o u r c e s a n a l y s e s , y e t  amount  inadequate The  and  quality  of  for engineering earliest,  ranging  manually  from  read on a  recording  the  data  provided  are  often  purposes.  and s t i l l most common, source of r a i n f a l l  data are p o i n t raingauges. forms,  resources  A l t h o u g h these  simple  daily  gauges  take  vertical cylindrical  basis  to  sophisticated  reservoirs automatic  d e v i c e s t a k i n g measurements e v e r y few m i n u t e s ,  a l l provide only point accumulations  must  measurements.  be  interpolated  Areal from  many  variations  they and  a network of such  i n s t r u m e n t s and a r e t h e r e f o r e s u b j e c t t o e r r o r . Since  the  precipitation  1940's has  been  measurement of r a i n f a l l of  radio  wave  an  echoes  alternative evolving  i s accomplished from  regions  method  of  sensing  using  radar.  Radar  by the  interpretation  of hydrometeors i n the  6  atmosphere.  It  distribution  of  provides  information  on  the  spatial  the p r e c i p i t a t i o n w i t h a t e m p o r a l r e s o l u t i o n  comparable t o or b e t t e r than t h a t of a r e c o r d i n g because i t remotely  gauge,  but,  senses the p r e c i p i t a t i o n , i t i s more prone  t o ^ e r r o r than d i r e c t gauge r e a d i n g s . A  more  data i s  recently  satellite  coverage  of  the for  constraints  make  hence  imagery. earth  information  and  to  Satellites  and  are  macroscale  data  radar  an  rainfall  wide-range source  However,  of  resolution  over s m a l l b a s i n s i m p r a c t i c a l  does  data  provide  invaluable  systems.  measurements  satellite  alternative  d e v e l o p e d p o t e n t i a l source of  not  appear  to  offer  an  i n s m a l l b a s i n s and urban r u n o f f  studies. 2.4  Hydrologic  Implications  In the c o n t e x t of s m a l l precipitation  source which i s m o s t l y  runoff response.  As the  critical  response  runoff  c h a r a c t e r of  the  events.  While  yet,  way  no  resolutions  area  of  and  it  is  the  basin  more  increases  dependent  eventually  the  t h i s i s suggested by e x p e r i e n c e , of  specifying  what  microscale  r e s p o n s i b l e f o r the peak  the  becomes  mesoscale  temporal  its  upon the macroscale  t h e r e i s , as and  spatial  are adequate f o r any p a r t i c u l a r b a s i n or r e g i o n .  Because of the c o s t and experience  basins,  has  been  h a v i n g s p a t i a l and  difficulties gained  temporal  with  involved, precipitation  resolutions  which  very data  little bases  approach  or  7  exceed  minimal  requirements.  Radar  measurement  p r e c i p i t a t i o n now o f f e r s t h e promise of p r o v i d i n g much resolution in the past.  precipitation  higher  d a t a bases than have been a v a i l a b l e  T h i s form o f measurement i s d e s c r i b e d i n  in'the following chapter.  of  detail  8  CHAPTER I I I  RADAR MEASUREMENT OF PRECIPITATION 3.1 I n t r o d u c t i o n  In  this  chapter  both  the t h e o r e t i c a l  and  practical  a s p e c t s o f t h e measurement of r a i n f a l l by c o n v e n t i o n a l groundbased r a d a r systems a r e c o n s i d e r e d .  A f t e r o u t l i n i n g the basic  p r i n c i p l e s of r a d a r , t h e r a d a r e q u a t i o n used i n studies  precipitation  i s d e v e l o p e d , f o l l o w e d by a d i s c u s s i o n of some of t h e  l i m i t a t i o n s t o t h e use of r a d a r as a chapter  concludes  with  an  measurement  examination  of  tool. an  The  existing  o p e r a t i o n a l r a d a r system, t h e Canadian Atmospheric Environment S e r v i c e s SCEPTRE r a d a r , from which t h e r a i n f a l l d a t a  used  in  t h i s r e s e a r c h was o b t a i n e d . 3.2 P r i n c i p l e s of Radar  Radar  has been d e f i n e d as a "system f o r a s c e r t a i n i n g t h e  d i r e c t i o n and range o f o b j e c t s from t h e e l e c t r o m a g n e t i c which t h e y r e f l e c t " measurement  by  [Oxfo5l].  radar,  I n t h e c o n t e x t of p r e c i p i t a t i o n  t h e o b j e c t s a r e hydrometeors such as  rain droplets,  ice particles,  scattering  reflection  or  waves  and  snowflakes  of r a d i o waves.  subsequent a n a l y s i s o f t h e r e f l e c t e d  energy  which  cause  The d e t e c t i o n and patterns  yields  i n f o r m a t i o n on t h e c h a r a c t e r i s t i c s of t h e p r e c i p i t a t i o n . In  a  typical  radar  system, a s i n g l e antenna s e r v e s as  9  b o t h t h e t r a n s m i t t e r and r e c e i v e r of t h e distance  to  the  target  radio  energy.  The  i s d e t e r m i n e d from t h e time e l a p s e d  between t r a n s m i s s i o n and r e c e p t i o n of t h e waveform, w h i l e precipitation  intensity  i s related  to  t h e s t r e n g t h of t h e  r e t u r n e d s i g n a l ( f i g . 3.1). The t r a n s m i t t e d energy  F i g u r e 3.1 - R a d a r - d e t e c t i o n in short pulses relatively  generally  is  sent  of p r e c i p i t a t i o n  (about one m i c r o s e c o n d d u r a t i o n ) , s e p a r a t e d by  long  s i g n a l s are  the  silent  received.  about  periods The  pulse  during  which t h e r e f l e c t e d  repetition  frequency  300 t o 400 p e r second [ S a u v 8 l ] .  is  This factor  d e t e r m i n e s t h e maximum u s e f u l range of t h e r a d a r , which may be no g r e a t e r than the d i s t a n c e t r a v e l l e d by a r a d i o wave i n h a l f the i n t e r v a l between p u l s e s . too  short,  the  echo  from  I f t h e p e r i o d between p u l s e s a  distant  i n s u f f i c i e n t time t o r e t u r n t o t h e r e c e i v e r pulse  i s transmitted,  r e p e t i t i o n frequency  producing  image  target  will  before  have  the  wraparound.  is  next  A high  enhances t h e q u a l i t y of t h e image because  a l a r g e r number of p u l s e s a r e r e t u r n e d from each  target,  but  10  for  a g i v e n system power t h e energy output o f each p u l s e w i l l  be l o w e r .  The upper range l i m i t f o r a  repetition  frequency  of  300  radar  i s about  with  a  pulse  500  km,  with  a  the  measurement,  c o n s i d e r a b l y s h o r t e r p r a c t i c a l range. In o r d e r t o maximize t h e p r e c i s i o n  of  the t r a n s m i t t e d beam-width i s made as narrow as p o s s i b l e . transmitted  beam  p a t t e r n i s a f u n c t i o n of t h e s i z e and shape  of t h e antenna and t h e w a v e l e n g t h of t h e r a d a r . circular  The  parabolic  antenna,  By  using  a  a symmetric beam p a t t e r n w i t h a  h a l f power w i d t h of about one degree may  be  acheived ( f i g .  3.2) [ S a u v 8 l ] .  F i g u r e 3.2 - T y p i c a l antenna beam p a t t e r n  To  obtain  a  complete  t h r e e - d i m e n s i o n a l s u r v e y of t h e  p r e c i p i t a t i o n system, t h e r a d a r  must  scan  through  multiple  11  elevation  angles  azimuth.  as  well  The r e t u r n e d  comprehensive  as  r o t a t e through 360  r a d a r echoes a r e i n t e g r a t e d t o  picture  of  the  precipitation.  r o t a t e s a t about s i x r e v o l u t i o n s per minute, through  the  elevation  complete c y c l e t a k e s  degrees of  angles  about  under  five  The  and  computer  minutes,  the  is  form  a  antenna stepped  control. actual  A time  depending on t h e number of e l e v a t i o n a n g l e s scanned.  3.3  The Radar E q u a t i o n  In  order  to  quantitatively  determine  the p r e c i p i t a t i o n  o b s e r v e d by t h e r a d a r , a r e l a t i o n s h i p between r e t u r n e d power  and p r e c i p i t a t i o n i n t e n s i t y i s r e q u i r e d .  Probert-Jones  [Prob62] and B a t t a n [ B a t t 5 9 ] d e v e l o p such an e q u a t i o n . g i v e s t h e power r e c e i v e d by a  radar  antenna  signal  for  Battan  scattering  from a s i n g l e t a r g e t as .  p  f  t p°i A  (3 1  where P  i s the t r a n s m i t t e d  t  power, A  p  i s the a p e r t u r a l a r e a of  a p a r a b o l o i d a l antenna, A i s t h e wavelength of t h e r  is  the  distance  -°  t o t a r g e t , and  radiation,  i s the b a c k - s c a t t e r i n g  c r o s s - s e c t i o n , which i s d e f i n e d as " t h e a r e a i n t e r c e p t i n g t h a t amount of return  to  power  which,  the  receiver  actually received." and  i f scattered an  amount  isotropically, of  would  power e q u a l t o t h a t  The e f f e c t i v e a p e r t u r e i s a f u n c t i o n of A  t h e g a i n of t h e a n t e n n a , G, which i s d e f i n e d as "the r a t i o  of t h e power r a d i a t e d by an  isotropic  antenna  necessary  to  12  produce  a  given  field  strength  power r a d i a t e d by a d i r e c t i o n a l field  strength  at  the  maximum t r a n s m i s s i o n " '  a t a given distance t o the  antenna  same  distance  the  the  same  i n t h e d i r e c t i o n of  [Prob62],  I n t h e case of hydrometeors, a  intercept  producing  radar  beam  at  large  any  one  group time,  r e t u r n e d s i g n a l i s an i n t e g r a t i o n of i n d i v i d u a l  of  targets  and thus t h e signals  from  each o f t h e p a r t i c l e s w i t h i n t h e volume i l l u m i n a t e d . When t h e received  power  i s averaged  over  a  l a r g e number of random  a r r a y s o f p a r t i c l e s , e q u a t i o n 3.1 becomes n I  (3.2)  l-o  with  the  scattered  summation signal  over  a  volume  i s received.  V  This  from which t h e backvolume  is  given  a p p r o x i m a t e l y by  V - *(rl)(r±) \ 2 2 2  (3.3)  where 6 and • a r e t h e h o r i z o n t a l respectively, (fig.  and  -|  and  vertical  beam  widths  i s t h e l e n g t h of t h e t r a n s m i t t e d p u l s e  3 . 3 ) . Thus t h e r a d a r e q u a t i o n may be r e w r i t t e n as  72X r 2  The  (3.4)  2  scattering  of  radio  energy  by a s i n g l e s p h e r i c a l  13  pulit  Itngth  ^  azimuth beomwidth 6  • livation btamwidth dS  F i g u r e 3.3 - Beam v o l ume d r o p l e t i s g i v e n by t h e R a y l e i g h a p p r o x i m a t i o n |K|2  '1 - 64  A  [Batt59]  6  (3.5)  A*  where  A  i s t h e wavelength o f t h e r a d i a t i o n , K i s t h e complex  index o f r e f r a c t i o n which i s a index  of  the  transmission  function medium  c o e f f i c i e n t of the target m a t e r i a l ,  of  the  refractive  and t h e a b s o r p t i o n  and a  ±  i s the droplet  radius. The  average r e t u r n e d power from a r e g i o n of hydrometeors  may now be c a l c u l a t e d by s u b s t i t u t i n g i n e q u a t i o n 3.4 t o y i e l d p  r  . 8*5  —r—  Probert-Jones  p  t p * , A  e  h  K r  2  1  V  [Prob62] c o m p l e t e s a s i m i l a r d e r i v a t i o n u s i n g a  more a c c u r a t e b u t complex e s t i m a t e of t h e i l l u m i n a t e d to y i e l d  (3.6)  volume  14  P A|6*h t  i V  log 2 e  where A  i s the  e  adjusted  effective  (3.7)  aerial  10  l o g  Z, 1  which  f o r l o s s e s i n t h e waveguide and radome.  the s i z e of t h e p a r t i c l e s by t h e i r symbol  aperture,  the  ). a  0  ±  *  diameters  and  is A  p  Specifying using  the  r e f l e c t i v i t y factor i n decibels, to represent  equation  becomes  3.7  V  P  r  -  —1 64  _L_£ log„2  \  A  ±J_ /  6  r  Z  (3.8)  2  T h i s e q u a t i o n may be broken down i n t o f i v e segments. first  term  i s a constant.  The terms w i t h i n t h e p a r e n t h e s e s  a r e c h a r a c t e r i s t i c s of t h e r a d a r and a r e a l s o c o n s t a n t given  system.  For  The  for a  d r o p l e t s of water i n t h e atmosphere, t h e  |K.| term i s a p p r o x i m a t e l y e q u a l t o 0.93, and f o r i c e p a r t i c l e s 2  i s about 0.19, but 0.93 i s g e n e r a l l y used s i n c e t h e t a r g e t  is  assumed  of  to  be  water  [Sauv8l].  precipitation i s primarily a  function  Thus  the  detection  of  the  size  hydrometeors  and t h e i r d i s t a n c e from t h e r a d a r .  in  signal  returned  accomodated  in  the  power r  2  with  increasing  of  the  The d e c r e a s e distance  is  term, w i t h n o r m a l i z a t i o n of t h e range  a c c o m p l i s h e d by " s e n s i t i v i t y time c o n t r o l . " The d e r i v a t i o n of t h i s e q u a t i o n i s based on a a s s u m p t i o n s , t h e most i m p o r t a n t of which a r e :  number  of  15  1. the  radar  reflectivity  is  uniform  over the  illuminated  volume; 2. the R a y l e i g h  approximation i s v a l i d  r e l a t i v e t o the 3. the  (droplet size i s  small  wavelength);  illuminated  volume  is  completely  filled  with  hydrometeors; 4.  a l l echoes come from the same type  of  hydrometeor  (rain,  snow, e t c . ) ; 5. the  beam  i n t e n s i t y c r o s s s e c t i o n can be a p p r o x i m a t e d by a  normal c u r v e ; 6. the amount of m u l t i p l e s c a t t e r i n g i s n e g l i g i b l e ; 7. the  incident  polarized Under  and  back-scattered  operational  conditions,  p r e c i s i o n of the r a d a r The  Z-R  are  linearly  [Croz75].  w i t h i n a f a c t o r of about 1.5,  3.4  radiation  Z  is  generally  accurate to  on the o r d e r of the  measurement  [Sauv8l].  Relation  Precipitation  i n t e n s i t y (R) must be r e l a t e d t o the  radar  r e f l e c t i v i t y f a c t o r (Z) b e f o r e measurements of r a i n f a l l can made.  S i n c e the d i s t r i b u t i o n of d r o p s i z e s i s  known  and  varies  in  time and  space, and  the  ground  t h e o r e c t i c a l Z-R  in  relation  d i f f e r e n t researchers between Z and  the  form is  of  not  generally  since v e r t i c a l a i r  c u r r e n t s o f t e n e x i s t which e f f e c t the r a t e a t reach  not  be  which  droplets  p r e c i p i t a t i o n , an possible.  A  exact  number  of  have e s t a b l i s h e d e m p i r i c a l r e l a t i o n s h i p s  R for various  r a i n and  snow c o n d i t i o n s  [Mars48],  16  [Wexl48],  [Best50],  [ J o n e 5 5 ] , [Gunn58], a l l o f which take t h e  form  Z - aR  where  (3.9)  b  a and b a r e c o n s t a n t s .  The M a r s h a l l - P a l m e r r e l a t i o n i s  the most w i d e l y used f o r t h e measurement of the  coefficients a  and  respectively [Wils79],  b  have  the values  3.8). to  f o r which  200  by a r a d a r  For meteorological twenty  cm  (equation  work, wavelengths i n t h e range  are generally  used  (table  3.1).  Band  Wavelength Range  Frequency  Uses  K  0.75 - 2.4 cm  25 GHz  cloud physics research  X  2.4 - 3.75 cm  10 GHz  weather s u r v e i l l a n c e (on board a i r c r a f t )  C  3.75 - 7.5 cm  6 GHz  p r e c i p i t a t i o n measurement  S  7.5 - 15 cm  3 GHz  p r e c i p i t a t i o n measurement, terminal a i r - t r a f f i c c o n t r o l  L  15 - 30 cm  1 .3 GHz  route a i r - t r a f f i c  wavelengths a r e a p p r o p r i a t e smaller  for cloud physics  d r o p l e t s may be d e t e c t e d ,  to attenuation.  one  Shorter  control  systems  studies,  since  w h i l e f i v e t o t e n cm r a d a r s  a r e p r e f e r r e d f o r p r e c i p i t a t i o n measurement because susceptible  1.6  i s quite  t o t h e wavelength of t h e r a d i a t i o n chosen  T a b l e 3.1 - F r e q u e n c i e s used i n weather r a d a r  less  and  [Sauv8l].  The minimum d r o p l e t s i z e d e t e c t a b l e sensitive  rain,  Because  r e q u i r e much more p o w e r f u l t r a n s m i t t e r s and  they a r e  t e n cm systems larger  antennas,  17  five  cm  practice  radars  a r e most  common  i n Canadian  operational  [Sauv8l].  3.5 L i m i t a t i o n s t o Radar Measurement of P r e c i p i t a t i o n Each r a d a r system must useful  measurement  computed u s i n g Probert-Jones v a l u e s were predicted  be  tool.  equation  less  the  i t becomes  measured  that  than  received  power,  on average t h e measured  1.5  dB  lower  than  those  serious  limitations  sources  of  error  i n the  t o t h e d e t e c t i o n c a p a b i l i t y of  radar. The  repetition  theoretical frequency  maximum  range  defined  by  distance  pulse  3.4).  At  a  of about 400 km from t h e r a d a r t h e beam, even a t i t s  minimum e l e v a t i o n a n g l e ,  will  pass  p r e c i p i t a t i o n systems [ W i l l 7 3 ] . also  the  may be superceded by a n o t h e r c o n s t r a i n t :  the e f f e c t o f t h e c u r v a t u r e of t h e e a r t h ( f i g .  may  a  Even f o l l o w i n g c a r e f u l c a l i b r a t i o n ,  t h e r e remain p o t e n t i a l l y and  and  showed  by t h e t h e o r y .  before  Based on t h e c o r r e l a t i o n o f v a l u e s 3.7  [Prob62] slightly  measurements  calibrated  be  a  limiting  over  the  t o p of  most  The output power of t h e r a d a r  factor.  The minimum t h r e s h o l d of  s i g n a l d e t e c t i o n may determine t h e e f f e c t i v e maximum range  of  a low power system. Attenuation  of  the  radar  beam  by  intervening  p r e c i p i t a t i o n , c l o u d s , and a t m o s p h e r i c gases may be a problem, 3.5).  particularly  f o r shorter  Of t h e s e , a t t e n u a t i o n  by  serious  wavelength r a d a r s ( f i g .  precipitation  i s t h e most  18 radar biom - radius ef curvature it 1.33 time* thot of the earth  F i g u r e 3.4 - E f f e c t  of the curvature of the e a r t h  F i g u r e 3.5 - A t t e n u a t i o n o f t h e r a d a r beam by i n t e r v e n i n g precipitation important.  F o r a f i v e cm r a d a r , W e i b l e and Sirmans [Weib76]  g i v e t h e a t t e n u a t i o n as  A  where  - I_ Rj ' 0  ±  A  A  9 9 2  0.00374Ar  i s t h e a t t e n u a t i o n r a t i o e x p r e s s e d i n dB, R j i s t h e  true r a i n f a l l  intensity  i n mm/hr f o r t h e j t h beam segment, and  Ar i s t h e l e n g t h o f t h e segment i n km. is  (3.10)  The a t t e n t u a t i o n r a t i o  19  A  - 10 l o g  ±  1 0  -f  (3.11)  T  where R ' i s t h e a t t e n u a t e d  r a i n f a l l rate.  Using t h i s  relation,  s  equation  3.10 may be r e w r i t t e n i n a more u s e f u l form as R  1  n  10  0 . 00037»»  R,  0 # 9 9 2  Ar  (3.12)  j-i  For example, t h e r e c o r d e d decreases  about  r a i n f a l l r a t e on  five  cm  radar  one mm/hr f o r every ten km i n which the beam  p a s s e s t h r o u g h ten mm/hr p r e c i p i t a t i o n . rainfall  a  The e f f e c t f o r h i g h e r  r a t e s i s even more s i g n i f i c a n t , and s e v e r a l  authors  [Weib76], [ H i t s 5 4 ] , [ A t l a 5 l ] recommend a g a i n s t u s i n g a f i v e cm radar  for quantitative  measurement  of  severe  storms.  a d d i t i o n , the minimum d e t e c t a b l e r a i n f a l l r a t e i n c r e a s e s distance  from  the  measurements which  radar.  Thus,  are s p a t i a l l y  to obtain  independent,  In with  consistent t h e minimum  s i g n a l t h r e s h o l d f o r t h e e n t i r e a r e a scanned by t h e radar must be  set to a  level  corresponding  t o the minimum d e t e c t a b l e  p r e c i p i t a t i o n r a t e a t the maximum range. The  b u i l d u p o f a p r e c i p i t a t i o n f i l m on t h e s u r f a c e of t h e  radome a l s o a t t e n u a t e s t h e r e c e i v e d thickness  of  the f i l m  varies  with  signal,  and s i n c e t h e  t h e a n g l e and s u r f a c e  c h a r a c t e r i s t i c s o f t h e radome s h e l l , the amount o f a t t e n u a t i o n i s a f u n c t i o n of the e l e v a t i o n beam.  Kodaira  angle  and d i r e c t i o n  of the  [Koda80] p r e d i c t s an i n c r e a s e i n a t t e n u a t i o n o f  20  over t h r e e dB f o r f i v e mm/hr o r more p r e c i p i t a t i o n a t t h e s i t e of  a  f i v e cm r a d a r , w h i l e W i l s o n  [ W i l s 7 8 ] contends t h a t t h i s  v a l u e s h o u l d be o n l y one dB f o r up t o f o r t y mm/hr r a i n f a l l . Wilson  and Brandes  microphysical  [Wils79]  some  of  collision  of  radar  rainfall  and c o a l e s c e n c e  measurements.  of d r o p l e t s ,  s o r t i n g i n r e g i o n s of s t r o n g i n f l o w and o u t f l o w , and updrafts  are  precipitation. droplet  the  and k i n e m a t i c e f f e c t s on t h e Z-R r e l a t i o n s h i p ,  and hence on t h e a c c u r a c y Evaporation,  summarize  given  Similarly,  breakup,  underestimates.  as  and  causes  of  vertical  overestimation  accretion  of c l o u d  vertical  downdrafts  size  of  particles, lead  These " p r o c e s s e s a c t i n c o m b i n a t i o n  to  t o modify  the d r o p - s i z e d i s t r i b u t i o n and produce a complex n e t r e s u l t . " There resolution  a r e two p r i n c i p l e of the radar.  factors  Firstly,  which since  limit  each  the  target i s  i l l u m i n a t e d by t h e e n t i r e l e n g t h o f t h e e m i t t e d p u l s e , an echo i s r e t u r n e d which i s one p u l s e l e n g t h l o n g e r than itself.  The  receiver  processor  t r a v e l l e d by t h e p u l s e t o determine with  halves  the target  the t o t a l distance  t h e range of  the o b j e c t ,  t h e r e s u l t t h a t a l l echoes appear l o n g e r by h a l f a p u l s e  length.  Thus  the radar  i s incapable  of  distinguishing  d i s t i n c t t a r g e t s which l i e on t h e same a z i m u t h a l l i n e and have a  separation  o f l e s s than  w i t h a two microsecond The  ^  ( f i g . 3 . 6 ) . F o r a radar s e t  p u l s e e m i s s i o n , t h i s d i s t a n c e i s 300 m.  second problem i s due t o t h e i n c r e a s e i n t h e w i d t h o f t h e  beam w i t h d i s t a n c e from t h e r a d a r ( f i g .  3 . 7 ) . F o r example, a  21  •2 s e p a r a t e c e l l s oppeor os a s i n g l e echo  t F i g u r e 3.6 - L i m i t a t i o n of r e s o l u t i o n due t o p u l s e  length  2 separate cells appear as a t i n g l e echo  F i g u r e 3.7 - L i m i t a t i o n of r e s o l u t i o n due t o beam w i d t h one  degree beam has a w i d t h of over f o u r km a t a range of 240  km.  As a consequence,  separation  of  discrete  targets  with  an  azimuthal  l e s s than one beam w i d t h produce a s i n g l e echo  r e t u r n , and t h e p r o b a b i l i t y t h a t t h e e n t i r e i l l u m i n a t e d volume i s not f i l l e d w i t h hydrometeors i n c r e a s e s as grows.  t h e beam  width  The net e f f e c t i s a l o s s of r e s o l u t i o n , l e a d i n g  t o an  a v e r a g i n g o r smoothing of i n t e n s i t i e s a t l o n g e r ranges. Poor s i t i n g o f t h e r a d a r antenna may l e a d t o problems ground  c l u t t e r and reduced a c c u r a c y of measurements made  s m a l l beam buildings  elevation and  angles  vegetation  [Smit72].  close  to  d i s t a n t mountains, may p a r t i a l l y o r beam  at  certain  angles ( f i g .  Obstacles  such  of with as  t h e r a d a r s i t e , or more  completely  obstruct  3 . 8 ) . These o b j e c t s  the  not o n l y  22  F i g u r e 3.8 - O c c u l t a t i o n of t h e r a d a r beam prevent  measurements from b e i n g made  i n their  shadows,  o f t e n appear as anomolous p r e c i p i t a t i o n i n t h e r e c o r d e d With can  but  data.  a p p r o p r i a t e p r o c e s s i n g software the spurious data p o i n t s be  removed,  but  little  can  be  done  o c c u l t a t i o n "holes" i n the area covered There  are  to  repair  by t h e r a d a r .  two f a c t o r s which l i m i t t h e u s e f u l n e s s of t h e  radar a t short ranges.  The f i r s t  i s the e f f e c t of s i d e l o b e s ,  which may produce echo d i s t o r t i o n s f o r t a r g e t s w i t h i n twenty km of t h e r a d a r . angle  of  ten to  S e c o n d l y , s i n c e t h e maximum e l e v a t i o n  t h e radar i s u s u a l l y l e s s than f o r t y d e g r e e s , t h e r e  i s a cone-shaped a r e a around t h e r a d a r silence")  the  i n which  (known a s t h e "cone  of  no measurements a r e p o s s i b l e ( f i g . 3.9)  [Sauv8l]. Electromagnetic density  change  waves r e f r a c t when they  i n the  atmosphere  decreases  microwaves  do  not  transmission  i n density travel  in a  with  through  medium.  Since  increasing  a  the  height,  s t r a i g h t l i n e , but i n s t e a d  f o l l o w a p a t h which i s v e r y n e a r l y t h e a r c of radius  pass  a  circle  with  about 1.33 times t h a t of t h e e a r t h ( t h e f a c t o r depends  on a t m o s p h e r i c c o n d i t i o n s but g e n e r a l l y l i e s between  1.1  and  23  d u * to ground eluttor ond t f t t c t of ( i d * lobe*  F i g u r e 3.9 - Cone o f s i l e n c e 1.6)  [Batt59].  When  t h e temperature and h u m i d i t y  d e v i a t e from normal c o n d i t i o n s , such as d u r i n g anomolous  propogation  occurs.  an  Superrefraction  gradients inversion,  i s abnormal  downward bending of the beam, w h i l e abnormal upward bending i s termed s u b r e f r a c t i o n .  Both of t h e s e phenomena l e a d t o s p a t i a l  d i s t o r t i o n of t h e p r e c i p i t a t i o n superrefraction  i s more  measurements,  insidious,  since  ground some d i s t a n c e from the r a d a r s i t e a r e 3.10).  but  excessive  echoes  from the  possible ( f i g .  Another problem i s d u c t i n g : under c e r t a i n a t m o s p h e r i c  c o n d i t i o n s t h e beam may be c h a n n e l e d i n a duct which a c t s as a wave g u i d e and d i r e c t s t h e beam l o n g d i s t a n c e s w i t h i n a narrow l a y e r near t h e s u r f a c e of t h e e a r t h . The l a s t s o u r c e of measurement e r r o r t o be c o n s i d e r e d t h e " b r i g h t band" e f f e c t . level  the  intensity  is  I n t h e area j u s t below t h e f r e e z i n g  o f r a d a r echoes may i n c r e a s e by s e v e r a l  o r d e r s of magnitude, due  primarily  to  the melting  of the  24  ground  F i g u r e 3.10 hydrometeors  - S u p e r r e f r a c t i o n of the r a d a r beam  (which  changes  t h e i r r e f l e c t i v i t y and t e r m i n a l  velocity) [Batt59]. The  potential  limitations  sources  outlined  of  combine  error  to  and  measurement  significantly  a c c u r a c y of d a t a o b t a i n e d from the r a d a r system. as  reduce  the  Some,  such  the e f f e c t s of ground c l u t t e r , s i d e l o b e s , and the cone of  s i l e n c e , are temporally relatively  easy  to  and  spatially  correct  invariant,  [Geot76],  [Aoya78],  and  thus  [Tate78].  R e s o l u t i o n problems due t o beam w i d t h , p u l s e l e n g t h , and  range  a r e more d i f f i c u l t t o overcome, but a r e d e t e r m i n a t e and can taken i n t o a c c o u n t . meteorological functions  of  difficult  phenomena, both  to  implementation system be  However,  space  adjust of  radar  the and  and for into  effects anomolous  time,  [Orms72]. a  attenuation,  propogation  exceedingly  The  "successful measurement  requires that c a r e f u l e l e c t r o n i c c a l i b r a t i o n  by  comparing  disdrometer  radar  measurements.  procedures  check of system b i a s e s be  estimates  with  rain  gauge  may  or  systematic  little  value.  or  Data u s e r s s h o u l d be c o g n i z a n t of  t h o s e c o n d i t i o n s i n which the r a d a r r a i n f a l l have  are  are  precipitation  f o l l o w e d and t h a t an independent  made  and  of  be  The  search  for  be  erroneous error  25  patterns  holds  unabiguously  promise,  but  until  such  e s t a b l i s h e d i t w i l l be n e c e s s a r y  patterns  can  be  t o use gauges t o  adjust the radar" [Wils79]. 3.6 D i g i t a l Techniques f o r Q u a n t i t a t i v e R a i n f a l l Measurement  Early  radar  measurements  s t u d y i n g images on p l a n  of p r e c i p i t a t i o n were made by  position  h e i g h t i n d i c a t o r (RHI) scopes. signal  from  the  radar  indicator  (PPI) or  range  W i t h t h i s equipment, t h e v i d e o  was  processed  t o produce an analog  d i s p l a y w i t h a r e f r e s h l i n e moving on t h e s c r e e n t o match  the  t r a v e l of t h e antenna. The  signals  returned  by  t h e hydrometeors  exhibit  s i g n i f i c a n t f l u c t u a t i o n s i n i n t e n s i t y , caused by rearrangement of t h e p a r t i c l e s due both t o movement of t h e hydrometeors w i t h r e s p e c t t o each o t h e r and movement of t h e whole mass to  the  radar  [Batt59].  p r o c e s s i n g of radar integrating  the  With  signals,  sequence  the  some  of  relative  i n t r o d u c t i o n of d i g i t a l  method  of  averaging  or  pulse returns i s required (the  p e r s i s t e n c e of t h e s c r e e n phosphor has t h e e f f e c t of a v e r a g i n g the s i g n a l i n an a n a l o g d i s p l a y [ C r o z 7 5 ] ) . A device c a l l e d the d i g i t a l (DVIP)  has  been  developed  video  which  integrator  converts the input analog  s i g n a l s t o d i g i t a l r a d a r echo i n t e n s i e s . processor  are  synchronization filters  logarithmic information.  t h e incoming  processor  The  inputs  t o the  r a d a r v i d e o t o g e t h e r w i t h antenna The  processor  recursively  signal, applies a distance normalization  26  correction, translates  samples  discrete  i t to digital  integrated d i g i t a l space  in  specified  range  form.  Output  intervals,  and  i s i n t h e form o f  i n t e n s i t y v a l u e s f o r each b i n (a volume by  a  fixed  range,  of  a z i m u t h , and e l e v a t i o n  angle) [Glov72]. A p r e c i p i t a t i o n map can be g e n e r a t e d referenced  spatially  i n t e n s i t y d a t a by c o n s t r u c t i n g a c o n s t a n t a l t i t u d e  plan p o s i t i o n i n d i c a t o r combining  from t h i s  intensity  (CAPPI).  values  from  A  CAPPI  segments  i s produced  of p r o g r e s s i v e l y  lower a n g l e PPI's w i t h i n c r e a s i n g range t o generate corresponding  to a  roughly  curvature of the e a r t h ( f i g .  Range gate  by  an  image  constant a l t i t u d e , allowing f o r 3.11).  Beyond  that  distance  allowance for curvoture of the eorth  F i g u r e 3.11 - CAPPI C o n s t r u c t i o n from  the radar  where  t h e l o w e s t beam a n g l e i n t e r s e c t s t h e  CAPPI e l e v a t i o n , t h e CAPPI becomes e q u i v a l e n t t o a  P P I . The  27  advantage  of  u s i n g a CAPPI f o r p r e c i p i t a t i o n s t u d i e s i s t h a t  the e f f e c t s of t h e v a r i a t i o n  in  rainfall  intensity  due  to  c h a n g i n g measurement h e i g h t a r e reduced, and i n a d d i t i o n i t i s not  as  affected  by  t h e problems of ground c l u t t e r near the  r a d a r as a low e l e v a t i o n a n g l e P P I . 3.7 The SCEPTRE Radar  A t m o s p h e r i c Environment S e r v i c e s weather  radar  systems  operates  a c r o s s Canada ( f i g .  a  3.12).  number  of  The most  F i g u r e 3.12 - AES weather r a d a r i n s t a l l a t i o n s i n Canada r e c e n t l y developed o p e r a t i o n a l Constant  system,  SCEPTRE  (System  for  E l e v a t i o n P r e c i p i t a t i o n T r a n s m i s s i o n and R E c o r d i n g ) ,  28  i s a network o f r a i n f a l l measurement r a d a r s which produce r e a l time CAPPI's and r e c o r d p r e c i p i t a t i o n f o r a r c h i v e SCEPTRE i n s t a l l a t i o n s a r e r e m o t e l y s i t e d f i v e which  operate  unattended  t r a n s m i t t i n g CAPPI centre.  (with  facsimiles  routine  purposes. cm r a d a r s  weekly s e r v i c i n g ) ,  t o the nearest  AES weather  Remote o p e r a t i o n a l l o w s a c h o i c e o f s i t e which g i v e s  the b e s t coverage o f the a r e a independent o f t h e l o c a t i o n o f the  weather  office.  The SCEPTRE u n i t c o n s i s t s o f the r a d a r  i t s e l f t o g e t h e r w i t h c o n t r o l and d a t a p r o c e s s i n g equipment and software ( f i g .  3.13).  t r a n s n l t t v r  dup1«x«r  wav*0u1d« components  I RADAR CONTROL  CENTRE  tapa a r c M v a PPI a n d control conao1 a  control a n d data procaaalng alnlcoaputar  facalMlIt aachlna  PROCESSOR CONTROL  CENTRE  F i g u r e 3.13 - SCEPTRE r a d a r  schematic  Each i n s t a l l a t i o n has a 250 kW Raytheon  WSR-807  radar  29  (table  3.2)  housed  i n a weather-proof radome a t o p a f i f t e e n  Transmitter:  Wavelength Frequency Nominal Peak Power P u l s e Length P u l s e R e p e t i t i o n Frequency Receiver: R e c e i v e r System Minimum D e t e c t a b l e S i g n a l Dynamic Range  5.3 cm 5.450-5.825 GHz 250 kW 2.0 ± 0.1 „s 324 ± 1 logar1thmlc -104 dB 80 dB  Antenna: R e f l e c t o r Type R e f l e c t o r Diameter Feed Type Feed P o l a r i z a t i o n Gain S i d e Lobe Level Scan Rate E l e v a t i o n Range Radome  paraboloid 3.658 m horn vert1ca1 43 dB -25 dB 6 rpm -2.5' t o 45' 5.8 m diameter p l a s t i c on aluminum space frame  General: Minimum D e t e c t a b l e Z Minimum D e t e c t a b l e R  13 dB 0.2 mm/hr  T a b l e 3.2 - Raytheon WSR-807 r a d a r metre s t e e l tower ( f i g . r e c e i v e r equipment  (fig.  the  the  tower,  with  3.14).  The  transmitter  antenna d i s h and p e d a s t a l mount  i n t h e radome on t h e f l o o r above.  site  shelters  minicomputer  radar  t h e PPI  indicator 3.17) as  A small  and well  on  c o n t r o l console ( f o r as  a  DEC  PDP-11/35  which m o n i t o r s and c o n t r o l s t h e o p e r a t i o n of the  Devices  Company  provided  s p e c i a l i z e d s i g n a l p r o c e s s i n g and Each  (fig.  building  3.18).  system and p r o c e s s e s t h e d i g i t a l r a d a r s i g n a l s ( f i g . Computing  and  3.15) a r e l o c a t e d i n an e n c l o s u r e on  3.16)  manual o p e r a t i o n ) ( f i g .  specifications  the  system  DVIP  control  and  other  hardware.  s i t e a l s o has a f a c s i m i l e machine t o d i s p l a y t h e CAPPI's  b e i n g t r a n s m i t t e d t o t h e l o c a l weather  office  (fig.  3.17),  30  F i g u r e 3.14  and  two  - R a d a r t o w e r and c o n t r o l b u i l d i n g a t A b b o t s f o r d SCEPTRE s i t e  9-track  magnetic  s y s t e m s o f t w a r e and The are  real  what  cm  radar  t h e DVIP o u t p u t  stages.  The  A scan  e l e v a t i o n and  the  SCEPTRE  i s not v e r y d i f f e r e n t  processes  one  the  r e c o r d i n g the a r c h i v e d a t a .  distinguishes  five  d r i v e s used f o r l o a d i n g  time computer d a t a p r o c e s s i n g and  equipment i t s e l f other  tape  the  systems. using  a  control  network  -  the  from t h a t found  The  PDP-11  hierarchy  of  system radar i n many  minicomputer three  scan  i s a single pulse return corresponding  azimuth  angle.  The  summation  of  A  to  scans  31  F i g u r e 3.15 - T r a n s m i t t e r , r e c e i v e r , and antenna equipment over  one  complete  r e v o l u t i o n of the antenna  i s one B scan (a  s i n g l e A scan i s shown on the o s c i l l o s c o p e  (fig.  the  a  PPI  displays  the  B  scan).  With  frequency of 324 p u l s e s per second and an ten  seconds,  degree  there  of azimuth.  a  predetermined  scans  which  while  antenna  period  of  a r e 3240 A scans per B scan, or nine per A complete  three dimensional survey of the  elevation  angle.  normally uses a c y c l e of twenty-nine C  3.19)  pulse r e p e t i t i o n  p r e c i p i t a t i o n i s a C scan, made up of a set of B at  control  correspond  to  The  scans,  SCEPTRE  B scans t o produce  particular  DVIP  each system three  operational  32  I  F i g u r e 3.16 - 3.66 m d i a m e t e r p a r a b o l i c a n t e n n a a n d p e d a s t a l mount s e t t i n g s and r a n g e s ( t a b l e 3.3)  [CDC 7 9 a ] .  The s y s t e m h a s a t w e n t y m i n u t e p r o c e s s i n g c y c l e w h i c h divided  into  two  ten minute operation p e r i o d s .  period, data i s acquired, processed, CAPPI  charts  [CDC 7 9 b ] . the  are  produced  and  and  of  the  o p e r a t i o n s , and d i f f e r e n t  data  azimuthal  during  degree,  minicomputer  the  eight  time  are  the  used  as  antenna CAPPI  computer a c t u a l l y p r o c e s s e s o n l y  approximately  these.  each  The  DVIP  3.20) and  source data i s used f o r each.  i s used t o produce the r e a l - t i m e CAPPI's. received  charts  two  on 9 - t r a c k t a p e a r e i n d e p e n d e n t  A l a r g e p o r t i o n of t h e a v a i l a b l e  scans  and  (fig.  The g e n e r a t i o n o f t h e r e a l - t i m e CAPPI  archiving  time  D u r i n g each  archived,  transmitted  is  signals  for  processor  Of t h e n i n e A sweeps  one  d a t a , but the one  s e t of e i g h t  half  of  scans are  33  Figure  accumulated those  values  stored  records  - PPI  i n 115  the range  data  a warning  with  each  than  two  percent  by  more  than  0.3  degrees.  complete  computer  each  position  scan  range  velocity  down  has been  also  of the  store.  I f gross  console  bin,  f o r the required  then  CAPPI  are  monitors  the  antenna,  and  I t i s programmed deviates  or the elevation  shuts  s e t of B scans  for  The computer  i f the angular  more  the  A  and c o n t r o l  gates  angular  by  occur  one  3.4).  (table  and e l e v a t i o n  this  indicator  registers,  within  i n memory  azimuthal  print  3.17  angle  antenna  the e n t i r e acquired  from is  s i x rpm  incorrect  positioning system. and  to  errors  Once  stored,  the scan  34  Figure  3.18  conversion  - PDP-11/35 m i n i c o m p u t e r equipment  takes  converted  to  place.  cartesian  precipitation  for  [CDC  79b].  An  the  charts  produced  operating  and  CAPPI  elevations.  levels  of  echo (in  top, winter  km,  long only)  polar  each  and  intensity  transmitted,  t h e amount The  of  system 7 km,  range  ( i n summer  displays  11  is  based  on  i s  [Hori80].  and  only), The  15  to  at  charts  km,  as  and high charts,  of  calculated select  the time  precipitation  km,  maps a r e area  used  can generate  4 km,  control  the  level  d e c i s i o n program  and  system  precipitation  coordinates  elaborate  period  1.5  The  and  of the various  at  CAPPI  well  as  sensitivity  which  include  35  Figure  3.19  Table  system  3.3  the  the  chart  levels 72]  single  A  scan  B Scans  Range  Bin Size  Normal  1 - 19  240 km  2 km  Long Range  20 - 24  360 km  3 km  High S e n s i t i v i t y  25 - 29  120 km  2 km  - SCEPTRE  C  scan  information  local  weather  i s sent  are  showing a display  C Scan  status  to  [Try  - Oscilloscope  in  (fig.  a n d a map  centre  analog  available, 3.21).  range  over  No  and s e n s i t i v i t y  overlay, a  mode,  depicted  a n d t h e PPI  are  telephone only  as  software  four  different was  options  transmitted  line.  Because  precipitation grey  included  levels in  the  36  PROCESSING CYCLE TIMING  Data Acqulaltlon (B Scana)  Data Acquisition (B Scana)  Data Procaaalng  Scan Convaralon  U  Chart Production Chart Transnlsalon  '•t Operating Parlod  2nd Oparatlng Parlod 10  ao  Tlaa (alnutaa)  F i g u r e 3.20 - P r o c e s s i n g c y c l e t i m i n g c h a r t  Scan No.  Elevation Angle (degrees)  Normal CAPPI Range 1 . 5 km 4 . 0 km (km) (km)  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19  0 .50 0 80 1 19 1 60 2 10 2 60 3 19 3 88 4 69 5 60 6 69 7 88 9 30 11 10 13 19 16 10 19 69 2 5 . 88 2 9 . OO  92 72 54 44 34 30 24 20 18 14 12  -  240 92 72 54 44 34 30 24 20 18 14  190 146 130 102 88 72 62 52 44 38 30 28 22 20 16 12  _  -  -  -  240 190 146 130 102 88 72 62 52 44 38 30 28 22 20 16  Gate SettIngs 7 . 0 km 11.0 (km) (km)  224 198 166 142 122 104 88 74 64 54 46 40 32 30 22 20 16 12  -  -  -  -  -  240 224 198 166 142 122 104 88 74 64 54 46 40 32 30 22 20 16  236 208 180 156 132 116 98 84 72 62 52 44 36 30 26 12  km  -  240 236 208 180 156 132 116 98 84 72 62 52 44 36 30 26  15.0 (km)  234 204 176 152 132 112 98 82 72 58 50 40 34 18  km  - 240 - 234 - 204 - 176 - 152 - 132 - 1 12 98 82 72 58 50 40 34 -  T a b l e 3.4 - Normal CAPPI c o n s t r u c t i o n t a b l e : range gate s e t t i n g s and c o r r e s p o n d i n g e l e v a t i o n a n g l e s SCEPTRE  system  t o remove  s t a t i o n a r y echoes, so r e c t a n g u l a r  grey a r e a s were added t o t h e o v e r l a y map t o mask r e g i o n s  from  37  Figure  3.21  - An e x a m p l e o f a C A P P I f a c s i m i l e A b b o t s f o r d SCEPTRE installation  from  the  38  which ground echoes were r e c e i v e d . One  complete  a r c h i v e r e c o r d i s w r i t t e n on magnetic tape  d u r i n g each o p e r a t i n g p e r i o d .  This  record  contains  system  s t a t u s f l a g s as w e l l as DVIP and antenna p o s i t i o n d a t a . ni-nth all and  A  scan i s used as the source of the a r c h i v e d a t a , w i t h  two km range b i n s r e c o r d e d which l i e w i t h i n lower  elevation  gate  settings  preset  The data i s  w r i t t e n a t 1600 b p i on 730 m 9-track magnetic tapes which to  AES  headquarters  Records from t h i s a r c h i v e of for  the  near  Toronto  operational  are  f o r storage.  precipitation  f i v e SCEPTRE r a d a r s are a v a i l a b l e t o the p u b l i c  AES [AES 8 1 ] .  upper  (twenty-two and zero km  r e s p e c t i v e l y ) f o r each e l e v a t i o n angle [CDC 79b].  forwarded  Every  data from  39  CHAPTER IV  RADAR-DERIVED PRECIPITATION MEASUREMENTS OVER THE VANCOUVER AREA 4/1 I n t r o d u c t i o n  Data o b t a i n e d from an o p e r a t i o n a l p r e c i p i t a t i o n  measuring  r a d a r near A b b o t s f o r d p r o v i d e d t h e b a s i s f o r t h e a n a l y s i s i n this  chapter.  The  source  of t h i s i n f o r m a t i o n and i n h e r e n t  e r r o r s i n t h e images d e r i v e d from i t a r e d i s c u s s e d . measurements  are correlated  with  raingauge  The r a d a r  data  and t h e  r e s u l t s o f t h i s comparison of a r e a l and p o i n t measurements a r e considered.  The  c h a p t e r c o n c l u d e s w i t h a d e s c r i p t i o n of t h e  image d i s p l a y system used and t h e p a t t e r n s seen i n t h e images produced. 4.2 The A b b o t s f o r d SCEPTRE Radar I n s t a l l a t i o n  Continuous Vancouver  area  spatial became  precipitation available  observations  i n late  A b b o t s f o r d SCEPTRE radar began o p e r a t i o n . south  of  A l d e r g r o v e , B.C.  1978  f o r the  when  the  L o c a t e d f i v e km due  ( a t 49° 0' 56" l a t i t u d e ,  122° 29'  11" l o n g i t u d e [Hans82]), t h e r a d a r scans a 240 km r a d i u s  area  which  the  encompasses  southern  portion  t h e lower of Vancouver  Washington S t a t e ( f i g . rainfall  measurements  mainland,  Gulf  Island,  islands,  and  northwestern  4.1). This radar i s i d e a l l y s i t e d f o r over  greater  Vancouver  since the  40  F i g u r e 4.1 - L o c a t i o n of the A b b o t s f o r d SCEPTRE r a d a r w i t h cone of s i l e n c e and 20 km range r i n g s marked m e t r o p o l i t a n a r e a l i e s between f i f t e e n and s i x t y - f i v e km the  radar:  inside  outside  the  range  precipitation  the t w e l v e km r a d i u s cone of s i l e n c e of  the  that  1.5  km  true  CAPPI.  by  However,  useable  i n t e r v e n i n g mountains,  records  r e l a t i v e l y s m a l l area ( f i g . 4 . 3 Data O b t a i n e d  are  available  with  for  only  to  from the AES  ensure  a  the a  4.2). Archive  A l l SCEPTRE r a d a r t a p e s r e c e i v e d a t AES h e a d q u a r t e r s processed  and  measurement i s o b s c u r e d over a l a r g e p o r t i o n of  the a r e a w i t h i n 240 km result  from  standard  b e f o r e they e n t e r the a r c h i v e .  are  format and q u a l i t y c o n t r o l  Incoming r e c o r d s  are  f o r b o t h r a d a r and p r o c e s s o r c o n s i s t e n c y by p r o c e d u r e s  checked such as  41  F i g u r e 4.2 statistically comparing  analyzing  adjacent  vertically,  - Coverage of 2 km CAPPI  to  bins  detect  the and  recorded scans,  anomolous  both  bit  patterns  and  horizontally  and  conditions.  Data which i s  s u s p e c t e d t o be i n e r r o r i s not c o r r e c t e d or d e l e t e d , flagged  and  e n t e r s the a r c h i v e .  c o m p i l e d f o r each r a d a r s i t e Radar p r e c i p i t a t i o n  is  Monthly e r r o r summaries are  [Hogg78].  records  for  several  of  the  s e v e r e storms over the Vancouver a r e a from the time the became  but  o p e r a t i o n a l i n 1978 t o the f a l l of 1981  most system  were r e q u e s t e d  42  from AES.  Due t o r a d a r and/or computer m a l f u n c t i o n s , d a t a f o r  most o f t h e s e storms was n o t a v a i l a b l e ( t h e A b b o t s f o r d SCEPTRE r a d a r was u n s e r v i c e a b l e f o r a major p o r t i o n o f t h e f i r s t years for  of i t s o p e r a t i o n ) .  two  P a r t i a l storm r e c o r d s were o b t a i n e d  f i v e e v e n t s between December 1979 and March  1981  (table  4.1). 1.  0004 GMT 2216 GMT  12 Dec 1979 t o 0624 GMT 12 Dec 1979 t o 1114 GMT  12 Dec 1979 14 Dec 1979 -  0 missing 3 missing  records records  2.  1204 GMT 25 Dec 1979 t o 0004 GMT 28 Dec 1979 - 14 m i s s i n g  records  3.  0O04 GMT  10 J u l 1980 t o 2124 GMT  10 J u l 1980 -  0 missing  records  4.  2354 GMT  19 Dec 1980 t o 1954 GMT 22 Dec 1980 -  0 missing  records  5.  O004 GMT 1944 GMT  11 Feb 1981 t o 0244 GMT 17 Feb 1981 t o 2354 GMT  0 missing records 0 missing records  16 Feb 1981 18 Feb 1981 -  T a b l e 4.1 - Storm r e c o r d s r e c e i v e d from AES  The d a t a from t h e a r c h i v e was p r o c e s s e d i n t o CAPPI images by  AES.  Processing  difficulties  CAPPI's from b e i n g produced  p r e v e n t e d s t a n d a r d 1.5 km  which had complete  a r e a , so AES chose t o generate CAPPI's 2000 m f o r t h i s p r o j e c t .  f o r an  of t h e  elevation  of  T h i s n e c e s s i t a t e d t h e c a l c u l a t i o n of  a new CAPPI c o n s t r u c t i o n t a b l e ( t a b l e 4.2). constructed  coverage  CAPPI images were  on a two km square c a r t e s i a n g r i d over t h e 240 km  r a d i u s range u s i n g t h e a r c h i v e d A scan r e c o r d s , one f o r each ten x  minute o p e r a t i n g p e r i o d .  These were f o r m u l a t e d i n t o a 240  240 m a t r i x c o n t a i n i n g t h e c i r c u l a r scan a r e a , t o which was  added a header f i e l d c o n t a i n i n g measurement,  and then  t h e time  and d a t e  of the  w r i t t e n onto 1600 b p i magnetic t a p e .  AES r e q u i r e d s e v e r a l months t o complete the d a t a t h a t was r e q u e s t e d f o r t h i s  t h e p r o c e s s i n g of  study.  a l l  43  E l e v a t i o n Angle (degrees)  Range Gate S e t t i n g s (km)  0.50 0.80 1 . 19 1 .60 2 . 10 2.60 3 . 19 3.88 4.69 5.60 6.69  114 - 2 4 0 86-114 68 86 56 68 44 56 38 44 32 38 2 6 - 3 2 2 2 - 2 6 18 22 14 .18  T a b l e 4.2 - 2 km CAPPI c o n s t r u c t i o n t a b l e  The  CAPPI g r i d s , which were r e c e i v e d on tape i n t h e form  of DVIP s i g n a l intensities  i n t e n s i t i e s , were c o n v e r t e d i n t o  precipitation  ( i n mm/hr) based on t h e c a l i b r a t i o n t a b l e  SCEPTRE r a d a r ( t a b l e  4.3) (For  D e t e c t i o n Level  DVIP I n t e n s i t y Value  0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15  0 8 16 24 32 40 48 56 64 72 80 88 96 104 112 120  -  7 15 23 31 39 47 55 63 71 79 87 95 103 111 119 127  P r e c i p i t a t i o n Rate (mm/hr) 0 0 . 25 0. 5 1 2 4 8 16 32 64 128 256 512 1024  t h r e s h o l d has been set a t t h e DVIP s i g n a l corresponds  to a  for the  the Abbotsford radar the noise  T a b l e 4.3 - SCEPTRE DVIP s i g n a l - r a i n f a l l c a l i b r a t i o n [Sauv8l]  which  [Hans82]  minimum  i n t e n s i t y of about one mm/hr.)  Over  intensity  l e v e l of t w e n t y - s i x ,  detectable 2000  image  precipitation grids  were  44  received,  representing  a  total  measurements f o r t h e f i v e storm  of  337  hours  of r a i n f a l l  events.  4.4 E r r o r s i n CAPPI Data  "  When t h e CAPPI  became a p p a r e n t . the  original  images  radar  of  expenditure  displayed,  several  errors  These e r r o r s came from two s o u r c e s : those i n measurements and those  the CAPPI p r o c e s s i n g correction  were  by  these  AES.  The  problems  introduced  analysis  and  required  a  during  attempted  considerable  of e f f o r t .  The most o b v i o u s e r r o r was t h e presence of c i r c u l a r r i n g s of h i g h e r  intensity precipitation.  noticeable events  i n the cumulative  which  were  These  were  particularly  r a i n f a l l p a t t e r n s f o r t h e storm  generated  by  summing  the  ten  minute  i n t e n s i t i e s over t h e d u r a t i o n of t h e storm and d i s p l a y i n g as a hyetal  surface  ( f i g . 4.3).  The  c o n c e n t r i c n a t u r e of t h e  r i n g s , c e n t r e d on t h e r a d a r s i t e , and t h e d i s t a n c e s the  peaks  occurred,  indicated  that  they  radar  remedial a c t i o n  return  It  was  variations measurements basis.  the  was  to  attempt  to  correct  the  data.  assumed  that  the  i n the height  at  were  Since  s i g n a l s were not a c c e s s i b l e , t h e o n l y  available  a l r e a d y processed  which  were an a r t i f a c t  i n t r o d u c e d d u r i n g t h e c o n s t r u c t i o n of t h e CAPPI. original  at  rings  were  which  caused  the  by the  precipitation  made, and c o r r e c t i o n was a t t e m p t e d on t h i s  T h i s was p o s s i b l y due t o a  portion  of  the  rainfall  45  F i g u r e 4.3 - U n c o r r e c t e d c u m u l a t i v e r a i n f a l l p a t t e r n f o r the December 1980 storm forming  in  the  v i c i n i t y o f t h e CAPPI a l t i t u d e , r e s u l t i n g i n  more p r e c i p i t a t i o n b e i n g measured below than  above  i t .  The  elevations  the of  measurements, c o r r e c t e d f o r t h e c u r v a t u r e standard  beam r e f r a c t i o n  CAPPI  the of  two the  elevation km earth  CAPPI and  (appendix A ) , v a r y between a minimum  46 of 1636  m a t a range of f o u r t e e n km and 5835 m a t 240  two km CAPPI i s e f f e c t i v e l y a 0.5 125  km  degree PPI beyond a range of  km). A  number  of d i f f e r e n t c o r r e c t i o n p r o c e d u r e s were t r i e d ,  i n c l u d i n g a t t e m p t s t o v a r y the amount of c o r r e c t i o n distance  from  the  radar,  with  actual  measurement  (fig.  4.4  factor  and  was  altitude  4.5).  close  to  one  value  (in  DVIP  to  exponentially.  which  A  profile  large  of  measured. for  An  the  variations  t o 1.1  f o r the  the from  in  is  uncorrected the  by  a p p l i e d t o the  intensity  radar  related cumulative  (fig.  4.6)  the amount of p r e c i p i t a t i o n  improvement i s noted i n  same  correction  i n t e n s i t y v a l u e s changed  rainfall  r a i n f a l l a t an azimuth of 270° the  the  amount because t h i s f a c t o r was  readings,  shows  of  the range 0.9  w o r k i n g image a r e a ) , the r a i n f a l l considerable  the  the nominal CAPPI e l e v a t i o n  A l t h o u g h the to  the  but the most s u c c e s s f u l a l g o r i t h m  used a m u l t i p l i c a t i v e f a c t o r based s o l e l y on the r a t i o of  a  (the  the  corrected  profile  storm which has a s i g n i f i c a n t r e d u c t i o n i n the  variation. The of the  t r u e c o r r e c t e d p r o f i l e i s not known but would be systematic  algorithm  does  not  ring  patterns.  completely  i t does reduce them and  increasing  range.  work  can  be  seen,  is  more  effective  with  would be r e q u i r e d t o o b t a i n a  complete c o r r e c t i o n method, but t h i s i s not w a r r a n t e d access  this  remove the p e r i o d i c i n t e n s i t y  s p i k e s , but  More  As  free  without  t o t h e o r i g i n a l d a t a as i t can b e s t be e l i m i n a t e d when  47  F i g u r e 4.4 - C o n v o l u t i o n p a t t e r n f o r image c o r r e c t i o n the  CAPPI's a r e g e n e r a t e d .  average  of  values  from  For example, by t a k i n g a bins  above  and  below  weighted the  CAPPI  a l t i t u d e , i t might be p o s s i b l e t o c o n s t r u c t an image f r e e from t h i s systematic error. A second problem w i t h t h e strong echos  data  was  s t a t i o n a r y echos i n t h e images. matched  elevations  the  great  elevation ( f i g .  locations  of  the  appearance  of  The p o s i t i o n of t h e s e  nearby  mountains  with  enough t o b l o c k the r a d a r beam a t the CAPPI 4.7).  No c o r r e c t i o n was made f o r t h i s s o u r c e  48  F i g u r e 4.5  - Corrected cumulative r a i n f a l l pattern December 1980 storm  of e r r o r because these anomolies  were e a s i l y i d e n t i f i e d i n the  images and do not occur i n the urban prime  regions  of  interest  f o r the  areas,  i n t h i s study.  which  were  T h i s problem  the has  been overcome i n o t h e r r a d a r a p p l i c a t i o n s , such as a i r t r a f f i c c o n t r o l , by p r o c e s s i n g the r a d a r s i g n a l s t o r e j e c t targets.  The  solution  to  moving t a r g e t  i n d i c a t o r (MTI)  software  each  at  SCEPTRE  this  problem  analysis  to  installation.  non-moving  i s f o r AES  t o add  their  processing  Prior  removal of  49 DECEMBER 20  i  1  1  1  1  1  1  1  UNCORRECTED PROFILE CORRECTED PROFILE  r  - 22  1980 STORM  — i — i —  -i  T  1  r  I  L  2 2  Z  < d —I w>  2 O  o  J  0.0  _l  L  tOX  20.0  L  30.0  -I  40.0  1  L  1  50.0  _l  60.0  L  -J  70.0  1  80.0  90.0  DISTANCE FROM RADAR SITE (KM)  WO.0  F i g u r e 4.6 - Comparison of c o r r e c t e d and u n c o r r e c t e d c u m u l a t i v e p r o f i l e s f o r December 1980 storm stationary  echoes  would  be  essential  f o r any  subsequent  s p a t i a l o r s t a t i s t i c a l a n a l y s i s by a user o f t h i s d a t a . In  a d d i t i o n t o t h e l o n g p e r i o d s of m i s s i n g r e c o r d s which  o c c u r r e d when t h e A b b o t s f o r d r a d a r was c o m p l e t e l y there  hours  duration,  Several  these  intervals  of  when  no  data  images  i n the  was  sequences.  i n gaps of  the  events one t o  A few o f t h e r e c o r d s had  i n c o r r e c t t i m e s o r d a t e s , but t h i s minor problem was when  recorded.  o c c u r r e d d u r i n g t h e storm  f o r which r e c o r d s were r e c e i v e d , r e s u l t i n g  correct  down,  were a l s o numerous s h o r t i n t e r v a l s , between t e n minutes  and s e v e r a l  twelve  shut  images were p r o c e s s e d h e r e .  easy  to  Another s m a l l  50  F i g u r e 4 . 7 - L o c a t i o n s of s t a t i o n a r y echoes e r r o r was t h e e x i s t a n c e o f h a l f images a t t h e end the  sequences,  presumably  of  due t o p r o c e s s i n g e r r o r s by AES.  These problems would most c e r t a i n l y f r u s t r a t e any automated p r o c e s s i n g of t h i s d a t a i n i t s p r e s e n t Accurate  reading  A  data  caused  on  a l l three  i n t e r p r e t a t i o n o f t h e images. same image read differing  values  from  tape  tapes  of  the  on  separate  to  using  form.  large  number  of  inconsistent  occasions  revealed  of some of t h e i n d i v i d u a l measurements, and of  r e c o r d was c o m p l e t e l y m i s s i n g .  was caused when t h e tapes were w r i t t e n a t either  to  Comparison of two c o p i e s of t h e  what was more s e r i o u s , i n about one p e r c e n t portion  attempt  of t h e t h r e e CAPPI d a t a tapes p r o v i d e d  by AES proved t o be another d i f f i c u l t y . errors  two of  very  AES,  the cases  a  T h i s problem and  was  due  o l d tapes or w r i t i n g on a d i r t y  tape  51  drive.  T h i s poor q u a l i t y d a t a p r o c e s s i n g does not  be c o n s i s t e n t w i t h the investment  appear  to  i n v o l v e d i n a l l of the p r i o r  phases of the a c q u i s i t i o n of t h i s i n f o r m a t i o n . 4.5  Comparison w i t h R a i n Guaqe Records  To  verify  the  accuracy  i n v e s t i g a t e the r e l a t i o n s h i p point-source  of  the r a d a r measurements and  between  precipitation  spatially-averaged  d a t a , the r a d a r - d e r i v e d e s t i m a t e s  of r a i n f a l l were compared w i t h raingauge studies  by  other  would, on average, the  gauges,  authors,  it  The  was  measurements.  expected  From  t h a t the radar  sense l e s s r a i n f a l l than t h a t  measured  in  and t h a t the magnitude of t h i s d i s c r e p a n c y would  v a r y from storm t o storm and radar s i t e .  and  increase with distance  These t r e n d s were a l s o observed  area  within  which  this  encompassed the lower m a i n l a n d , Vancouver I s l a n d .  Daily  from  in this  comparison was  G u l f i s l a n d s , and  a c c u l u l a t i o n s were  the  study. undertaken  southeastern  chosen  as  the  b a s i s f o r the comparison because of the p a u c i t y of gauges w i t h recording  frequencies  of  l e s s than t w e n t y - f o u r hours w i t h i n  t h i s a r e a and because random v a r i a t i o n s tend t o dominate  over  shorter  Five  p e r i o d s , making the comparison l e s s m e a n i n g f u l .  days of d a i l y  records  were  obtained  Record of M e t e o r o l o g i c a l O b s e r v a t i o n s  from  and  longitude  of  each  AES  Monthly  i n Western Canada  for  4.8).  The  n i n e t y - s e v e n s t a t i o n s i n B r i t i s h Columbia latitude  the  station  (fig.  ( g i v e n i n the  Monthly Record of M e t e o r l o l o g i c a l O b s e r v a t i o n s  i n Canada  AES  52  F i g u r e 4.8  - L o c a t i o n of AES raingauge records  Supplement) were c o n v e r t e d t o (UTM)  c o o r d i n a t e s by l o c a t i n g  topographic  map.  This  stations with daily  Universal  Transverse  Mercator  each s t a t i o n on a 1:50  000 s c a l e  coordinate  system  r e f e r e n c e g r i d f o r the comparison w i t h the radar  values  were  obtained  by  served  radar  summing over  as  data.  corresponded  radar  0754  record  on  the  next  t o the o b s e r v a t i o n p e r i o d f o r the d a i l y  d a t a ) and d i v i d i n g the  the  the t o t a l by s i x .  measurement  kilometre  square  raingauge  and  was  which  taken  contained  corresponding  radar  For comparison  -  point  data  are  one this  raingauge purposes,  as the v a l u e f o r the the  The  144 ten minute  i n t e n s i t i e s ( b e g i n n i n g w i t h the r e c o r d f o r 0804 l o c a l time day and ending w i t h  the  gauge.  twoThe  summarized i n  appendix B. To raingauge  analyze values,  the  correlation  linear  between  the  radar  and  r e g r e s s i o n s were computed f o r f i v e  53  days of d a t a  S  ( f i g . 4.9  through  4.13).  RADAR/RAINGAUGE CORRELATION i  ~i  1  1  1  1  1  1  1  1  1  In  each  case  the  DECEMBER 2 0 1980  1  1  r  1  "i  1  r  NUMBER OF OBSERVATIONS = 81 CORRELATION COEFFICIENT = 0.737 STANDARD ERROR OF ESTIMATE = 4.208  2 2  < or < o < cr  -  1  1  0  1  8  1  1  1  1  1  24  B  1  S2  1  40  i  i 48  i  •  t  5 6 '  i  i  64  •  •  72  80  RAINGAUGE MEASUREMENT (MM)  F i g u r e 4.9 - Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p f o r 20 December 1980 comparison * was correlation indicating  based  on  coefficients that  a  about ranged  strong  eighty between  observations. 0.665  and  error  of  estimate  0.737,  c o r r e l a t i o n e x i s t e d but a l s o that  t h e r e was s i g n i f i c a n t v a r i a t i o n from t h e best f i t l i n e . standard  The  (limits  of  The  d e v i a t i o n from t h e  54  RADAR/RAINGUAGE s  CORRELATION  -  DECEMBER  211980  j — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i —  _ NUMBER OF OBSERVATIONS = 81 _ CORRELATION COEFFICIENT = 0.665  p  . STANDARD ERROR OF ESTIMATE = 2.524  ie _  '  2  ui Ui  I  e  1  I  0  1  1  I  16  B  1  1  I  32  24  I  I  40  I  I  I  48  I  I  56  RAINGAUGE MEASUREMENT (MM)  I  I  I  72  64  I  I 60  F i g u r e 4.10 - R a d a r / r a i n g a u g e r e g r e s s i o n r e l a t i o n s h i p f o r 21 December 1980 regression observations  line  within  fall)  ranged  the r a d a r o v e r - e s t i m a t e d heavy  ones,  which  which  about  two-thirds  from 2.3 t o 5.8 mm.  light rainfalls  and  of the  I n a l l cases under-estimated  i s c o n s i s t e n t w i t h t h e f i n d i n g s of W i l s o n  and Brandes [ W i l s 7 9 ] , The  three-dimensional  hyetal surface representations f o r  both t h e r a d a r and r a i n g a u g e d a t a f o r 20 December 1980 ( f i g u r e  55  S  RADAR/RAINGAUGE CORRELATION I  I  I  1  1  1  1  1  1  1  - FEBRUARY  1—  — i — i —  12  "i  1981 r  1  NUMBER OF OBSERVATIONS = 80 CORRELATION COEFFICIENT =  0.711  STANDARD ERROR OF ESTIMATE = 2.293  to < or; <  < or  - i — i — i — i — i — i  ' 24  •  •  32  •  - j — i — i — i — i  40  48  56  i 64  RAINGUAGE MEASUREMENT (MM)  ' 72  i 80  F i g u r e 4.11 - Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p f o r 12 F e b r u a r y 1981 4.14)  serve  problem. only  to  illustrate  t h e c o m p l e x i t y of t h e c o r r e l a t i o n  The upper, r a d a r - d e r i v e d image  one-quarter  of  the  points  mountains,  not r a i n f a l l  computed  using  6300 i n d i v i d u a l measurements r a d a r  took over t h e a r e a , and shows adjacent  was  significant  (the very  high  variation  spikes  measurements).  The  between  a r e echos lower  from  picture,  computed from t h e i r r e g u l a r p a t t e r n o f e i g h t y - o n e l o c a t i o n s a t which  gauge  measurements  were  taken,  i s naturally  much  56  RADAR/RAINGAUGE  8  "T  1  1  1  1  1  CORRELATION 1  1  1  1  1— i  FEBRUARY 1  1  1  1  13 1  1981  1—~r  NUMBER OF OBSERVATIONS = 76 CORRELATION COEFFICIENT = 0.685 STANDARD ERROR OF ESTIMATE = 3.390  2> 2  -i  1  1—-—t  1  1 24  i  I  52  40  J  I  48  I  56  L  72  RAINGAUGE MEASUREMENT (MM)  80  F i g u r e 4.12 - Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p f o r 13 F e b r u a r y 1981 smoother because, on a v e r a g e , t h e measurement more The  locations are  than t h r e e times f u r t h e r a p a r t than those o f t h e r a d a r . raingauge  were  obtained  water. picture  surface includes less  area  because  values  f o r Washington S t a t e nor over r e g i o n s of open  D e s p i t e t h e much rougher s u r f a c e t e x t u r e o f t h e and t h e a r e a  of missing  data  expected.  To o b t a i n  radar  due t o t h e cone of  s i l e n c e , the o v e r a l l patterns of s p a t i a l v a r i a t i o n was  no  agree,  as  t h e same l e v e l o f p o i n t t o p o i n t  57  RADAR/RAINGAUGE CORRELATION s  FEBRUARY 14  1981  i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i —  . ~ . _  NUMBER OF OBSERVATIONS =  76  CORRELATION COEFFICIENT =  0.713  STANDARD ERROR OF ESTIMATE = 5.848  •* _  2 2  0  8  16  24  32  40  48  56  72  64  80  RAINGAUGE MEASUREMENT (MM)  F i g u r e 4.13 - Radar/raingauge r e g r e s s i o n r e l a t i o n s h i p F e b r u a r y 1981 variation  d e t a i l s seen i n t h e  radar  picture,  f o r 14  the  raingauge  network d e n s i t y would have t o be i n c r e a s e d f o r t y f o l d . The  ratios  of  gauge  t o r a d a r r a i n f a l l depth  were computed f o r t h e f i v e days overall  average  found by o t h e r variation  value  of  data  (table  4.4).  of 1.76 i s g e n e r a l l y l a r g e r  researchers,  but  i n t h i s r a t i o i s not.  t h e amount  of  estimates The  than t h a t day-to-day  I n a study of f o u r t e e n  storms  58  F i g u r e 4.14 - H y e t a l s u r f a c e r e p r e s e n t a t i o n s of r a d a r and raingauge d a t a f o r 20 December 1980 in  Oklahoma u s i n g a t e n cm r a d a r , W i l s o n and Brandes  [Wils79]  found an average r a t i o of 1.04, b u t measured r a t i o s as low  as  0.41 and as h i g h as 2.41, i n d i c a t i n g a g r e a t d e a l of v a r i a t i o n on a s t o r m - t o - s t o r m correlation.  b a s i s , and l i t t l e  i n d i c a t i o n of day-to-day  They r e p o r t t h a t " l a r g e wanderings i n t h e gauge  t o r a d a r r a t i o s a r e not unexpected i n  view  of  the  observed  59 Date  No.  of  Values  G/R  Mean  Coeff.  20  Dec 1980  81  1 .734  O .284  21  O e c 1980  81  2 . 146  0 .445  12  F e b 1981  80  1 .729  0 . 285  13 F e b 1981  7G  1 .218  0 . 382  14  70  1 .973  0 . 984  388  1 .761 .  0 . 595  F e b 1981  Total  of  Variation  T a b l e 4.4 - G/R r a t i o s f o r 5 days of r a i n f a l l  data  range i n r e p o r t e d Z-R r e l a t i o n s h i p s and t h e v a r i a b l e n a t u r e of the drop s i z e d i s t r i b u t i o n . "  The c o e f f i c i e n t o f v a r i a t i o n f o r  the  sixty  five  day  period  was  percent,  which  f a v o u r a b l y w i t h t h e s i x t y - t h r e e p e r c e n t observed Brandes, who go on t o s t a t e t h a t results  from  storm-to-storm  "much  of  compares  by W i l s o n and  the radar  error  d i f f e r e n c e s i n the r e l a t i o n s h i p  between r a d a r - r e c e i v e d power and r a i n f a l l r a t e " [ W i l s 7 9 ] . removing  By  t h e mean storm b i a s ( m u l t i p l y i n g t h e r a d a r v a l u e s by  the average gauge t o radar r a t i o f o r t h e storm)  they  reduced  t h e i r e r r o r ( c o e f f i c i e n t of v a r i a t i o n ) t o twenty-four  percent.  Humphries  and  Barge  [Hump79a]  observed  gauge t o radar  r a t i o s of 1.1 and 1.3 f o r p e r i o d s between f i v e and 420 minutes d u r i n g two summer's o p e r a t i o n of a t e n cm radar Although  t h e i r c o e f f i c i e n t s of v a r i a t i o n were q u i t e h i g h (230  and 240 p e r c e n t ) , they r e p o r t e d point  f o r long  p e r i o d s o f time  that  "accumulations  radar  t o a d j u s t t h e r a d a r measurements."  values,  over  a  (1-2 months) can be accepted  w i t h a h i g h degree of c o n f i d e n c e w i t h o u t u s i n g raingauge  i n Alberta.  a  calibration  Using  calibrated  they found a s u b s t a n t i a l i n c r e a s e i n t h e e r r o r  of t h e r a d a r e s t i m a t e s w i t h i n c r e a s i n g range  -  from  fifteen  60  p e r c e n t a t f i f t y km t o e i g h t y p e r c e n t a t 120km, w i t h r a t i o s a t greater  distances  showing  the p o i n t v a l u e s . with  distance  towards  The c o r r e l a t i o n  i n this  increasing  I  1  1  study  ratio  GAUGE/RADAR ~ I  a c o n s i d e r a b l e u n d e r e s t i m a t i o n of  1  1  1  distance  CORRELATED 1  ratios  showed t h a t t h e r e was a t r e n d  with  RATIO  o f t h e gauge/radar  1  r—  ~i  WITH  r  4.15)  (fig.  ~i  but  DISTANCE 1  1  r  NUMBER OF OBSERVATIONS = 388 CORRELATION COEFFICIENT = 0.135 O "!  L  STANDARD ERROR OF ESTIMATE = 1.037  i.i 9  or  in  <  or < < O <  W W J  L  6.0  310  47.0  63.0  79.0  95.0  1110  127.0  DISTANCE FROM THE RADAR SITE (KM)  143.0  159.0  175.0  F i g u r e 4.15 - G/R r a t i o a s a f u n c t i o n o f d i s t a n c e from t h e radar although  t h e r a d a r u n d e r e s t i m a t e d r a i n f a l l t o a g r e a t e r degree  further  from  the radar  site,  no i n c r e a s e i n t h e e r r o r was  shown  similar  observed. Other  studies  have  results.  Austin  61  [Aust80a]  found  that  by  using  "judicious"  c a l i b r a t i o n , a c c u r a c i e s on t h e o r d e r o f t h i r t y be  expected  raingauge  percent  could  f o r one. hour a c c u m u l a t i o n s , w h i l e H u f f e t . a l .  [ H u f f 8 0 ] and V o g e l [Voge80]  observed  that  under  real  time  o p e r a t i o n a l c o n d i t i o n s , twenty p e r c e n t was t h e b e s t e r r o r t h a t c o u l d be  achieved.  The  error  figures  given  have  a l l been  assumption t h a t t h e r a i n g a u g e d a t a was a c c u r a t e , measurements themselves may be Wilson  i n error.  but t h e gauge  Both  Austin  and Brandes note t h a t t h e raingauge e s t i m a t e s  rainfall  are accurate  widespread,  to  long-duration  for convective  within rain,  about  gradients  better  between  represents  the  and  possible raingauge  attenuation  elevation  with  distance  discussed  previously.  of from  causes  of  t h e beam, radar  i t is  accumulation Thus i t i s radar  [Aust80a].  the discrepancies  measurements.  the  then  a t t r i b u t e d t o the  f o r h y d r o l o g i c a l purposes"  a r e many  radar  variations,  amounts  a r e a than t h e p o i n t gauge measurement.  s h o u l d be so p l a c e d  pass  " I f there are s i g n i f i c a n t  i n t h e accumulated  not c l e a r t h a t a l l t h e e r r o r n o r m a l l y  There  percent f o r  f l o o d i n g i n Ottawa but which d i d not  p o s s i b l e t h a t t h e radar that  of a r e a l  b u t may be g r o s s l y i n e r r o r  over any of t h e gauges i n t h e c i t y . spatial  five  and  showers - A u s t i n makes mention of a storm which  caused s i g n i f i c a n t  over  based on the  and  Reflectivity changing  site  beam  have  been  In addition t o unrepresentative  gauge  s a m p l i n g , A u s t i n [Aust80b] p o i n t s out t h a t the method of  time  62  integration  of  the  radar  data  may  be i m p o r t a n t : the  i n t e g r a t i o n w i l l be i n e r r o r i f the time r e q u i r e d f o r  time  intense  echos t o move from one g r i d p o i n t t o an a d j a c e n t p o i n t i s l e s s that  the  i n t e g r a t i o n i n t e r v a l , as was  in^ t h i s study. derived  the c a s e w i t h the d a t a  These f a c t o r s must be c o n s i d e r e d  spatially-based  precipitation  when  data  is  radarused  in  engineering hydrological a p p l i c a t i o n s . 4.6  I n t e r a c t i v e Image D i s p l a y System  The  f o u r t e e n days of r a d a r data r e c e i v e d c o n t a i n e d a v a s t  amount of i n f o r m a t i o n . 45 000  Each  grid  consisted  of  over  p r e c i p i t a t i o n i n t e n s i t y measurements, y i e l d i n g a t o t a l  of more than n i n e t y - o n e hours  CAPPI  of  hydrology  records. this  m i l l i o n i n d i v i d u a l v a l u e s f o r the  337  For p r a c t i c a l a p p l i c a t i o n s i n e n g i n e e r i n g  enormous  reduced and p r e s e n t e d  amount  of  information  had  i n such a manner t h a t i t c o u l d be  to  be  easily  and m e a n i n g f u l l y a s s i m i l a t e d . The  first  s t e p i n the r e d u c t i o n i n v o l v e d the c h o i c e of a  subset of the r a d a r coverage a r e a . around  the  radar  l o n g i t u d e and it  48°  A  180  x  bounded by a p p r o x i m a t e l y 20' and 49°  140 121°  30' l a t i t u d e was  km  region  30' and  chosen  124°  because  i n c l u d e d the m e t r o p o l i t a n Vancouver and V i c t o r i a a r e a s  excluded  most  measurement  of  area.  the This  occluded reduced  portions by  amount of d a t a which had t o be p r o c e s s e d s a l i e n t f e a t u r e s of the images.  a  of  the  and  CAPPI  f a c t o r of seven the while  retaining  the  63  Presentation  of t h e d a t a i n a manner such t h a t t h e r e was  a l a r g e throughput of i n f o r m a t i o n w h i l e t h e i m p o r t a n t  features  were s t i l l e a s i l y d i s t i n g u i s h a b l e was t h e next c o n s i d e r a t i o n . Since  humans  have  a  "well-developed  two-  and  three-  d i m e n s i o n a l l y o r i e n t e d e y e - b r a i n p a t t e r n r e c o g n i t i o n mechanism which  allows  very  us  rapidly  pictorially"  t o p e r c e i v e and p r o c e s s many t y p e s of data  and  efficiently  i f the data  are  presented  [ F o l e 8 2 ] , some form o f a g r a p h i c a l r e p r e s e n t a t i o n  of t h e i n f o r m a t i o n was t h e o b v i o u s c h o i c e . . S e v e r a l a l t e r n a t i v e p i c t o r i a l formats were p o s s i b l e . simplest  method  involved  substituting a different  f o r each r a i n f a l l i n t e n s i t y image  ( f i g . 4.16).  t o produce  This  procedure  a  measured  from  key i s awkward because image  many  t h e image v e r y e a s i l y .  t o use, p a t t e r n of  the p i x e l  i s not v e r y  alternative  was  values  is  difficult  c h a r a c t e r s a r e s i m i l a r , and t h e pleasing.  maps ( f i g . 4.17).  The  second  Although  r e p r e s e n t a t i o n , which i s f a m i l i a r t o e n g i n e e r s , a l l o w s to  be  interpolated  rectilinear unusual  from  coordinates  contours  t h e map, of  which  the  t h e s t e e p g r a d i e n t s and  radar  are d i f f i c u l t  method of p r e s e n t a t i o n a l s o o b s c u r e s of  the data.  this values  data to  often  produce  interpret,  p a t t e r n s c a n be d i f f i c u l t t o f o l l o w from image t o image.  format  to  However, t h e p i x e l  recognition  aesthetically  isohyetal  matrix  inexpensive,  produces an unambiguous i n t e r p r e t a t i o n , and a l l o w s be  character  character  i s very  The  the e s s e n t i a l l y  and This  matrix  P r e s e n t a t i o n of t h e r a i n f a l l data as a  64  F i g u r e 4.16  - C h a r a c t e r m a t r i x r e p r e s e n t a t i o n of the patterns  rainfall  65  1934GMT 80/12/20  1944GMT 80/12/20  1954GMT 80/12/20 F i g u r e 4.17 - I s o h y e t a l r e p r e s e n t a t i o n of t h e r a i n f a l l patterns  66  three-dimensional  s u r f a c e was a n o t h e r o p t i o n ( f i g . 4.18).  t h i s format p a t t e r n s a r e r e l a t i v e l y easy follow  through  sequential  picture are impossible.  two  options  d i s t i n g u i s h and  images, but measurements from t h e  The l a s t a l t e r n a t i v e c o n s i d e r e d was a  c o l o u r image ( f i g . 4 . 1 9 ) . previous  to  In  This  has  an  advantage  over  the  because l e s s p r o c e s s i n g of t h e data i s  r e q u i r e d , w h i l e , g i v e n a s u f f i c i e n t l y l a r g e c o l o u r p a l e t t e , an unambiguous image can be o b t a i n e d on which p a t t e r n s a r e e a s i l y r e c o g n i z e d and from which measurements may be The  readily  c o l o u r p i c t o r i a l r e p r e s e n t a t i o n was chosen as t h e p r i m a r y  method of p r e s e n t a t i o n f o r t h e r a d a r - d e r i v e d r a i n f a l l in t h i s  amount and format of t h e data n e c e s s i t a t e d some  computer  processing  system.  A  variety  of  i n c l u d i n g a g r a p h i c s t e r m i n a l on a l a r g e m u l t i - u s e r a  patterns  study.  The of  made.  powerful  dedicated  image  microcomputer were c o n s i d e r e d .  analysis A  options, computer,  system,  microcomputer  type  and  with  a  colour  g r a p h i c s c a p a b i l i t y was chosen f o r t h e f o l l o w i n g r e a s o n s : 1. a v a i l a b i l i t y  and  low  cost:  disk storage, colour monitor, and  software  a complete system, i n c l u d i n g communications  c o u l d be purchased o f f t h e s h e l f f o r about  6000 d o l l a r s , and t h e t e c h n i q u e s here  could  interface,  easily  be  and  software  developed  t r a n s f e r r e d e l s e w h e r e and p l a c e d  i n t o immediate o p e r a t i o n ; 2. f l e x i b i l i t y : a microcomputer c o u l d be programmed t o a n a l y z e and modify t h e images as w e l l as d i s p l a y them; 3. ease of programming: microcomputer  software  i s generally  F i g u r e 4.18  - H y e t a l s u r f a c e r e p r e s e n t a t i o n of the patterns  rainfall  Figure  4.19  -  Colour  representation  of  the  r a i n f a l l  patterns  69  w r i t t e n i n BASIC - an easy t o l e a r n , i n t e r a c t i v e langauge with  built  in scientific  functions  and  higher-level  langauge c o n s t r u c t s ; 4. d e d i c a t e d use: t i m e - o r u s e - s h a r i n g systems impose c o s t and t i m e c o n s t r a i n t s on t h e a v a i l a b i l i t y particularly  where  contemplated,  but  real-time this  of  processing  i s not  the  the  computer,  of  images i s  case  with  a  microcomputer. However,  the choice  disadvantages.  of  a microcomputer was not w i t h o u t i t s  Probably  t h e most  important  drawback  was  p r o c e s s i n g speed: t h e s m a l l m i c r o p r o c e s s o r word s i z e ( e i g h t o r sixteen  bits)  and  narrow  data  path width ( g e n e r a l l y e i g h t  b i t s ) combined w i t h t h e r e p e a t e d r e p r o c e s s i n g of statements by the BASIC i n t e r p r e t e r painfully into  slow.  assembly  make  microcomputer  "number-crunching"  The performance can be improved langauge  those  segments  which  by r e c o d i n g consume t h e  g r e a t e s t number of machine c y c l e s , but t h i s d e c r e a s e s t h e ease with  which program m o d i f i c a t i o n s can be made and r e q u i r e s t h e  programmer t o have a much g r e a t e r i n - d e p t h computer  system.  Most  knowledge  of t h e  e n g i n e e r s a r e not p r e p a r e d t o i n v e s t  the amount of time r e q u i r e d t o g a i n t h i s knowledge, but as t h e r e q u i r e m e n t s o f most u s e r s of t h e r a d a r similar,  standard  second d i s a d v a n t a g e a  memory  restricts  software  i s memory s i z e .  addressability the s i z e  packages  of  e x e c u t e d w i t h o u t swapping.  would  be  very  c o u l d be d e v e l o p e d .  A  E i g h t b i t p r o c e s s o r s have  constraint programs  data  of  which  64K  bytes,  can  be  The newer s i x t e e n  which  l o a d e d and  b i t processors  70  overcome  this  problem, and  not g e n e r a l l y a  restriction.  T h i s e x p e n d i t u r e on a justified  on t h e s e machines program s i z e i s  in  microcomputer  system  view of the amount of p r e c i p i t a t i o n  which c o u l d be a c c e s s e d .  A number  were  the d e c i s i o n was  IBM  considered  000  before  P e r s o n a l Computer.  superior  The  IBM  of  was  processor a r c h i t e c t u r e  and  better  easily  information  microcomputer  systems  made t o purchase an  picked  because  had  a  ( s i x t e e n b i t word s i z e , 1  000  byte a d d r e s s a b i l i t y ) , h i g h e r r e s o l u t i o n  capability,  was  documentation  it  graphics  than any  display  of the  systems a v a i l a b l e a t the time f o r about the same c o s t . up t o d i s p l a y the CAPPI images, the as:  IBM  PC  (8088  bytes 2-5  processor)  computer  was  other As  set  configured  w i t h 40 K b y t e s ROM  and  128  K  RAM 1/4" per  floppy disk drives with  160K  storage  capacity  drive  RS-232 s e r i a l communications i n t e r f a c e Amdek RGB This  colour  equipment  was  monitor. set  up  in  a  E n g i n e e r i n g b u i l d i n g ( f i g . 4.20). included  the  disk operating  an 8086 a s s e m b l e r .  The  laboratory  i n the  Software provided  Civil  by  system, a BASIC i n t e r p r e t e r ,  image d i s p l a y  and  analysis  IBM and  programs  were w r i t t e n i n BASIC. To  transfer  d i s k e t t e s i t was equipped  the  CAPPI  data  onto  the  necessary to e s t a b l i s h a l i n k to  w i t h 9-track tape d r i v e s .  The  microcomputer a  U n i v e r s i t y of  computer British  71  F i g u r e 4 . 2 0 - IBM  Personal Computer used f o r d i s p l a y i n g the CAPPI images  Columbia m u l t i - u s e r MTS provided  by  AES  microcomputer.  system was  and  transmit  used  to  the  read  the  information  To save time, the mainframe was  also  tapes to  the  used  to  s e l e c t the working p o r t i o n of the g r i d , apply c o r r e c t i o n s , and convert  the  DVIP  procedures c o u l d microcomputer. computer was  values as  A  to r a i n f a l l  easily serial  installed,  been  communications  implemented link  and  using  software  the  Computing Centre,  systems  programmer  data was  t r a n s f e r r e d to the microcomputer and  disk  ( f i g . 4.21,  at  have  i n t e n s i t i e s , but  these  on  the  with the  provided  by  exists  a  the CAPPI g r i d  s t o r e d on  floppy  appendix C ) .  In a computer with a f i x e d c o l o u r d i s p l a y b u f f e r s i z e , trade-off  UBC  a  between the number of c o l o u r s a v a i l a b l e and  the r e s o l u t i o n of the  image.  To o b t a i n the screen  resolution  72  Q_D 9-track tap* drlva  Amdahl 470 waInfrana dlak drlvaa  0  IBM PC microcomputer  ••rial communications 11nk  o  floppy dlak drlvaa  F i g u r e 4.21 - MTS host - IBM PC d a t a t r a n s f e r l i n k necessary  t o d i s p l a y the 180 x 140 km r e g i o n (320 x 200 p i x e l  d i s p l a y mode), the number o f c o l o u r s p o s s i b l e was four.  limited  to  Thus o n l y f o u r p r e c i p i t a t i o n l e v e l s c o u l d be d i s p l a y e d  unambiguously.  This  could  be  increased  by  r e c y c l i n g the  c o l o u r s c a l e f o r h i g h e r i n t e n s i t i e s , a t the c o s t o f making t h e image more d i f f i c u l t t o i n t e r p r e t . creating  an  dithering.  Since  represented a  new  colour  recycle,  each  display  using  precipitation  grid  square  was  by m i x i n g two o f the b a s i c c o l o u r s w i t h i n one U s i n g t h i s p r o c e s s and a  were  map  produced.  To  limited  colour  scale  a i d the i n t e r p r e t a t i o n ,  an  of t h e a r e a was o v e r l a y e d on t h e s c r e e n ( f i g .  The n o r t h - s o u t h  e l o n g a t i o n o f t h e image i s due t o t h e  c l o s e r h o r i z o n t a l s p a c i n g o f t h e screen The  t h e p r i n c i p l e of  p r e c i p i t a t i o n images w i t h an i n t e n s i t y r e s o l u t i o n of  one mm/hr  4.22).  colour  by f o u r s c r e e n p i x e l s , i t was p o s s i b l e t o s i m u l a t e  g r i d square.  outline  eight  T h i s problem was s o l v e d by  microcomputer  was programmed  pixels. t o p r o v i d e a simple  73  A b b o t s f o r d SCEPTRE R a d a r  L o c a t i on Figure  4.22  interactive display area  monitor d i s p l a y showing overlay map  analysis  of  i t .  One  covered  by the  option  on  map was  in  graph  over  map  area  displayed. the  image  allows may  be  engineers experienced  as  form. f o r any  Combining display  area.  during  generate user  a  cursor  on  were  The  amount  of  period could  the  yields types  storm  a of  events  the  total  From  this  the  for  A any  location  screen,  and  d i s p l a y e d and  the then  accumulation  be  computed  and  data  analysis  with  powerful rainfall and  as  the  calculated.  rainfall  interactive  well  hyetograph  also  and  received during  selected  images  simple  see  be  the  capability to  a  as  level.  easily  The  positioning  compiled  plotted the  map  to  rings  o p t i o n computed  precipitation  could  programmed  w i t h i n the  hyetograph  of  range  data  intensity  depth  interval  was  by  precipitation  rainfall  total  location the  the  user-selectable  each  measurement  second  silence  - Colour  information each  o f padai* & cone o f  at  tool  patterns the  same  which which time  observe how  t h e s e r e l a t e t o the p o i n t h y e t o g r a p h s  accumulations  normally  used  in  design  and  rainfall  calculations.  This  i n t e r a c t i o n a i d s the development of an i n t u i t i v e f e e l f o r rainfall  data  and  promotes  c o n s i d e r a t i o n of the s p a t i a l  w e l l as the temporal m u t a b i l i t y  of  precipitation  in  the as  design  practice. 4.7  P a t t e r n s of P r e c i p i t a t i o n over the Vancouver Area  The p r e c i p i t a t i o n p a t t e r n s seen i n the 337 hours of r a d a r data  for  the  five  partial  storm  records  c h a r a c t e r i s t i c s t r u c t u r e s o u t l i n e d by E a g l e s o n area  covered  synoptic  by  scale  the  image  patterns.  precluded However,  exhibited [Eagl70].  observation  meso-  and  the The  of  any  microscale  s t r u c t u r e s were e a s i l y i d e n t i f i e d i n the p i c t u r e s . I t s h o u l d be noted t h a t the a c t u a l v a l u e s measured on the images  are  probably  t o o low by a f a c t o r of almost two.  causes of t h i s e r r o r , which v a r i e s i n have  already  been  outlined  in  both  time  previous  corresponds  to  space,  sections.  e l l i p t i c a l a r e a w i t h i n which no v a l u e s a r e g i v e n on the images (see the 1154Z  and  is  The  An  included  image t o gauge i t s e x t e n t ) - t h i s  the c i r c u l a r cone of s i l e n c e around the radar  site. The December  sequence of images ( f i g . 1980  area.  to  4.37)  from  the  storm show the p r e c i p i t a t i o n r e s u l t i n g from an  o c c l u d e d f r o n t of a Vancouver  4.23  low  pressure  system  passing  over  the  A "broad l o o s e band" of p r e c i p i t a t i o n w i t h a  75  .  19  ^ u i u  Radar average r a i n f a l l i n t e n s i t y  HX»XHJ t S l  M i n u t e  —.  HH/hr  1  Figure  4.23  - Rainfall intensity pattern December 1980 "V W  aal • .  n i n u t e average r a i n f a l l  -  1044  8 I 2  GMT  22  intensity MM/hr  Figure  "pebbly these  4.24  -  Rainfall intensity pattern December 1980  structure" cyclonic  i s t h e most  storms  striking  [Aust59]  and  -  1054  mesoscale is easily  GMT  22  feature identified  of in  76  Figure  4.25  - Rainfall intensity pattern D e c e m b e r 1980  -  1104 GMT  22  Figure  4.26  - Rainfall intensity pattern December 1980  -  1114  22  this  sequence.  northeasterly  This  well-defined  direction,  band  perpendicular  moved to  the  GMT  in  an  east-  line  of the  77  18 M i n u t e  average r a i n f a l l  |  Figure  Figure  front,  and  increased  4.27  4.28  1 **/hr  "—<  - Rainfall intensity pattern D e c e m b e r 1980  - Rainfall intensity pattern D e c e m b e r 1980  the average as  r~'  intensity  precipitation  i t approached  -  1124  1134  intensity  the mainland  coast.  GMT  GMT  in The  22  22  the  band  rainfall  78  Figure  Figure  ahead  4.29  - Rainfall intensity pattern D e c e m b e r 1980  -  1144  GMT  22  4.30  - Rainfall intensity pattern D e c e m b e r 1980  -  1154  GMT  22  patches  at  of the front  mesoscale  level  i s organized  ( f i g 4.19)  into  which  irregular  move  in step  as  the  the  cyclonic  79  10 Minute  a v e r a g e  fcf  «  .  i n t e n s i t y  1 MM/hr  *7  Figure  4.31  - Rainfall intensity pattern D e c e m b e r 1980  -  1204  GMT  22  Figure  4.32  - Rainfall intensity pattern D e c e m b e r 1980  -  1214  GMT  22  system the  r a i n f a l l  sweeps  rainfall  eastward. bands  Houze  from  et.  Pacific  a l .  [Houz76]  cyclonic  storms  classified into s i x  80  , •  10  • J  tm.»--»  M i n u t e  ait  •  w,  a v e r a g e  r a i n f a l l  i n t e n s i t y  F i g u r e 4.34 - R a i n f a l l i n t e n s i t y p a t t e r n - 1234 GMT 22 December 1980 categories according band.  They  noted  t o t h e type of f r o n t a s s o c i a t e d w i t h that  " i n some  cases  rainbands  the were  81  nju&nj V 3 i u m  J \ , t r I JVC  IVdltiajr  1 0 Minute a v e r a g e r a i n f a l l --T - 7 ^ — T — J  1  intensity 1 «*/h*  Figure  4.35  - Rainfall intensity pattern December 1980  -  1244  GMT  22  Figure  4.36  - Rainfall intensity pattern December 1980  -  1254  GMT  22  interspersed rain,  while  with in  larger  irregularly  shaped  other  cases  non-banded  small  regions  of  mesoscale  light rain  82  Figure  areas  4.37  observed  Fraser images.  over  generally the  the  is also band  the  is  the  of  area  moves  of  precipitation  than  effect  mountains  flow  of  which  the  keeps  River  the  the  the  due  not  bearing  to  rainbands.  this  sequence  of  until  the  north  The  portion  to  this moving  continued result  receives  only  northern  whereafter  which  the  areas  the  River  a l s o due  mesoscale  central  valley.  Fraser  rainfall  form  were  of  Vancouver,  to  the  lowlands but  in  22  findings  topography  lowlands  up  the  of  GMT  cold-frontal  coherent  north  progress  north  wide  visible  relative  Fraser  1304  Their  mountainous  in a  mountains  eastward  the  clearly  retarded  flat  bands."  -  w h e r e many n o n - b a n d e d  in addition to  The  reaches  the  study,  effect  River  portion  between  in this  The  end  Rainfall intensity pattern December 1980  occurred  confirmed were  -  the  is  over  that  greater  orographic  r e t a r d a t i o n of  airmass  its  the  the area  83  f o r a g r e a t e r p e r i o d of t i m e . obvious i n the l a t t e r half The  precipitation  of t h e upper a i r f l o w . from  this  sequence  T h i s phenomenon i s p a r t i c u l a r l y  of t h e image  bands move i n l a n d under t h e i n f l u e n c e The v e l o c i t y  of  a l l of  kilometre  per  t h e system  measured  of images was f i f t y k i l o m e t r e s p e r hour,  which was t y p i c a l of t h e v e l o c i t i e s storms,  sequence.  which  hour  fell  range  observed  i n the t h i r t y of  average  f o r the other to  sixty-five  frontal  velocities  measured by Hobbs and Biswas [Hobb79] over Washington Microscale images.  patterns  The i n d i v i d u a l  or b l u e i n t e n s i t y  level)  can  also  move  d i s t i n g u i s h e d i n the  convective c e l l s (generally at the red form w i t h i n t h e broad r a i n f a l l a r e a s .  A l t h o u g h o t h e r a u t h o r s [Hobb79], cells  be  State.  at a different  [Aust59] have noted t h a t  velocity  the  t o t h e g e n e r a l r a i n band,  t h i s phenomenon was not observed i n t h e over  300  hours  of  storm r e c o r d s h e r e : t h e c o n v e c t i v e c e l l s appeared t o remain i n position  relative  to  t h e broad r a i n f a l l a r e a s .  By t a k i n g a  l a g r a n g i a n p e r s p e c t i v e , t h e t e m p o r a l growth and decay individual the  c e l l s can be o b s e r v e d .  c e l l s remained  sixty  minutes,  identifiable  which  The i n t e r v a l s d u r i n g which ranged  i s typical  observed  i n only  d u r a t i o n o f t h e maximum shorter.  Eagleson  one  rainfall  between  thirty  The peak i n t e n s i t y  image, rate  indicating was  was  that the  t e n minutes  [ E a g l 7 0 ] has suggested t h a t t h i s  i s as s h o r t as a few m i n u t e s .  and  of t h e d u r a t i o n s found by  other researchers [Aust59], [Eagl70], usually  of t h e  or  interval  84  I t i s o n l y by o b s e r v i n g t h e s e p a t t e r n s t h a t one begins t o appreciate the complexity inherent complexity records.  not  at  a l l apparent  i n the  precipitation,  from c o n v e n t i o n a l  Current p r a c t i c e i s to analyze point  by" i g n o r i n g  t h e movement  of  a  hyetograph  rainfall  data  storms, assuming a s t a t i o n a r y  growth and decay, o r t o c o n s i d e r a c o n s t a n t r a i n f a l l r a t e over an a r e a f o r a c r i t i c a l time p e r i o d .  An e x p l i c i t c o n s i d e r a t i o n  of storm growth, v e l o c i t y , and t r a c k i s a p r e f e r a b l e approach, but t h i s  requires  variation  of p r e c i p i t a t i o n .  archive  together  sofware  developed  knowledge  of  the  spatial  and  The A b b o t s f o r d SCEPTRE radar d a t a  w i t h t h e data p r o c e s s i n g and v i s u a l here  temporal  provide  an  a s s i m u l a t e d source of t h i s i n f o r m a t i o n .  economical  and  display easily  85  CHAPTER V  HYDROLOGICAL APPLICATIONS OF SCEPTRE RADAR DATA 5.1 I n t r o d u c t i o n  Potential  applications  engineering hydrology outlining  o f SCEPTRE p r e c i p i t a t i o n data t o  are discussed i n t h i s  chapter.  g e n e r a l uses o f r a d a r - d e r i v e d r a i n f a l l  the p o s s i b i l i t y of u s i n g SCEPTRE d a t a as i n p u t runoff  models  i s investigated.  l i m i t a t i o n s of t h i s d a t a source demonstrated  in a  case  Both  information,  to  the  hydrologic  benefits  i n urban r u n o f f m o d e l l i n g  study  of  a  Vancouver  s i m u l a t e d u s i n g t h e Storm Water Management Model. concludes  and are  catchment The c h a p t e r  w i t h recommendations f o r improvements t o t h e SCEPTRE  r a d a r system and AES d a t a a r c h i v e t o data  After  and  improved  access  for  provide  higher  engineering  quality  hydrologic  applications. 5.2 G e n e r a l A p p l i c a t i o n s  There a r e many p o t e n t i a l a p p l i c a t i o n s f o r comprehensive, spatially-referenced primary  source  precipitation  of  p r e c i p i t a t i o n data. such  measurement  data,  was  Radar, which i s t h e first  use  for  i n t h e l a t e 1940's, but i t wasn't  u n t i l t h e development of d i g i t a l systems i n t h e its  adapted  i n engineering hydrology  1970's  became f e a s i b l e .  o n l y r e c e n t l y have a t t e m p t s been made t o  apply  that  Moreover,  radar-derived  86  rainfall  measurements t o e n g i n e e r i n g problems, and t h e use of  such d a t a i s s t i l l  f a r from r o u t i n e .  continues,  new  and  Research  applications will  in this  be  found  area  as t h e  r e l i a b i l i t y and a c c u r a c y of t h e r a d a r systems i s improved the  and  u t i l i z a t i o n of r a d a r - d e r i v e d p r e c i p i t a t i o n r e c o r d s becomes  a c c e p t e d by t h e g e n e r a l e n g i n e e r i n g community. Meteorological  r e s e a r c h i n t o t h e s t r u c t u r e of storms and  the p h y s i c s o f p r e c i p i t a t i o n was one of t h e f i r s t a p p l i c a t i o n s of weather r a d a r , and c o n t i n u e s t o p l a y New  techniques,  meteorology,  such  have  installations,  important  role.  as t h e a p p l i c a t i o n of d o p p l e r radar t o been  and  an  developed  at  the  research  t h e e x i s t i n g t e c h n o l o g y has been r e f i n e d  u s i n g t h e s e s i t e s as p r o t o t y p e s f o r o p e r a t i o n a l systems. literature but  most  contains of  many d e s c r i p t i o n s of t h i s r e s e a r c h work,  i t i s too theoretical  a p p l i c a t i o n i n engineering Currently,  The  to  have  immediate  hydrology.  the primary  use  of p r e c i p i t a t i o n - m e a s u r i n g  r a d a r i s f o r r a i n f a l l f o r e c a s t i n g . A network of t e n cm WSR-57 r a d a r s has been e s t a b l i s h e d f o r t h i s States,  while  purpose  i n the  United  i n Canada, t h e d i g i t a l SCEPTRE system i s used  principally i n this role.  Similar  of  weather  radar  c o u n t r i e s ( B r a z i l and Great  Britain  i n several  other  both o p e r a t e such equipment). overview  of  a l l of  use  i s made  Sauvageau  the p r e c i p i t a t i o n  [Sauv8l]  gives  an  f o r e c a s t i n g systems  c u r r e n t l y i n o p e r a t i o n i n Canada. One o f t h e a p p l i c a t i o n s o f  radar  rainfall  measurements  87  which  has  engineering  s i g n i f i c a n c e i s streamflow  and f l a s h f l o o d warning. input  This  utilizes  t o a r u n a f f model t o g e n e r a t e  real-time.  A runoff  spatially  model  the  prediction  radar  data  as  streamflow p r e d i c t i o n s i n  capable  of  making  use  of  the  d i s t r i b u t e d p r e c i p i t a t i o n input data i s r e q u i r e d i n  this situation.  Koren [Kore78] d e s c r i b e s an i m p l e m e n t a t i o n  f l a s h f l o o d p r e d i c t i o n i n the S o v i e t  Union.  In  the  of  United  S t a t e s , S a f f l e and Greene [ S a f f 7 8 ] i l l u s t r a t e another  approach  with  system.  a  case  Application  study of  u s i n g the D/RADEX d i g i t a l r a d a r  radar  data  to  qualitative  f o r e c a s t i n g i n A l b e r t a was demonstrated [Hump79b],  who  headwaters  to  computed enable  daily  streamflow  by Humphries and Barge  rainfall  hydrologists to  maps  for  predict  remote  streamflows  downstream i n more p o p u l a t e d a r e a s . R a d a r - d e r i v e d p r e c i p t i a t i o n d a t a has been u t i l i z e d real-time  control  Recent work by [Voge80],  of  Huff,  [Huff80]  reservoirs Towery,  of  the  and  storm sewer  Vogel,  and  Illinois  the v i a b i l i t y of r e a l - t i m e  conjunction  with  others  [Huff78],  radar  data  used  control,  and  this  in  p r e c i p i t a t i o n data i n r e a l - t i m e .  turn  Two  requires  weather  of  form  of  access  to  radars  dense r a i n g a u g e network a r e b e i n g used t o study the characteristics  in  The c o m p l e x i t y of the  sewer and storm d r a i n a g e system demands some  automated  has  raingauge measurements as d a t a  i n p u t t o an urban water c o n t r o l system. Chicago  systems.  S t a t e Water Survey  demonstrated  telemetered  i n the  and  a  time-space  storms and f o r e c a s t a r e a l r a i n f a l l i n the  m e t r o p o l i t a n Chicago a r e a .  James and Robinson  [Jame8l]  have  88  proposed  a  similar  system  f o r the Hamilton area.  In t h e i r  s t u d y , t h e m o n i t o r i n g of both t h e q u a l i t y and q u a n t i t y of t h e runoff  was  of  concern,  They proposed t o m i n i m i z e p o l l u t a n t  l o a d i n g s on t h e H a m i l t o n r e c e i v i n g w a t e r s by u s i n g a r e a l - t i m e control  system  based  Management Model  on  (SWMM).  analysis  using  t h e Storm  Water  A l t h o u g h t h e use of c a l i b r a t e d r a d a r  d a t a i s not s p e c i f i c a l l y mentioned i n t h e p r o p o s a l , a s u i t a b l e radar  system  would  be  a  practical  alternative  t e l e m e t e r e d r a i n g a u g e network t h a t was s u g g e s t e d .  t o the  The  real-  t i m e urban r u n o f f management t e c h n i q u e s o u t l i n e d above r e q u i r e accurate,  comprehensive, and t i m e l y p r e c i p i t a t i o n d a t a , and a  calibrated  weather  radar  is a  viable  source  of  such  information. Automated  r e a l - t i m e f o r e c a s t i n g of r a i n f a l l  r e q u i r e s the  r e c o g n i t i o n and e x t r a p o l a t i o n of p r e c i p i t a t i o n p a t t e r n s . r e s e a r c h e r s have been w o r k i n g t o d e v e l o p and  tracking  known  authors  clustering  algorithms.  radar  tracking.  field,  echoes In  and  papers  methods research  simple  correlation  demonstrated  f o r recognizing i s needed  local of  complexes  Neither  of  c o m p l e t e l y a c c u r a t e and f o o l p r o o f and  tracking  storm  cells:  i n t h i s a r e a b e f o r e automated  d r a i n a g e c o n t r o l systems such as t h a t can be s u c c e s s f u l l y  techniques.  used  t h e work  e t . a l . [ B r a d 7 8 ] , echoes were grouped i n t o  and t r a c k e d by these  recognition  to delimit  c o r r e l a t i o n p r o c e d u r e s f o r echo Brady,  identification  Blackmer and Duda [ B l a c 7 2 ] , w e l l -  i n the pattern  techniques  cell  Some  implemented.  envisaged  more  real-time  f o r Chicago  89  From  an  engineering  hydrology  most p r o m i s i n g a p p l i c a t i o n s o f is  i n the  study  of  d e t e r m i n i n g a more storm.  "The  Marshall, that  a  representative  precipitation-measuring  rainfall  realistic  verification few  patterns  of  the  the  of  radar  various  synthesized records.  from  a  that  study  data  kinds  extreme of  a  tracking  simultaneaously i d e n t i f i c a t i o n of except  cell  its  growth  design  contain  in a  convective  events  may  be  chapter,  convective  I n t h e c o n t e x t of  i n t e n s i t y i s u s u a l l y due t o  directly  reaching  to  a much s h o r t e r complete a r e a l  r u n o f f , the design r a i n f a l l cell  the  of  local  As was d e s c r i b e d i n a p r e v i o u s  single  of  view  over a l a r g e p e r i o d  r a i n f a l l c e l l s grow and decay as they move. urban  a  radar  s u g g e s t i o n , due t o J.S.  p r e c i p i t a t i o n t h a t can occur i n a l o c a l i t y of t i m e " [Druf76] means  with  representation  hours  way  p e r s p e c t i v e , one of t h e  over peak  and  a  basin  rainfall  movement  while  rate.  The  i s impossible  from a s p a t i a l d e s c r i p t i o n of t h e p r e c i p i t a t i o n , which  r e q u i r e s a v e r y l a r g e , dense gauge network o r a weather r a d a r . Hence t h e study of storm c e l l images  i s an  ideal  growth  rate,  from  the v a r i a b l i l i t y  spacing,  velocity,  characteristics  of  of  cell  storm size, Konrad  statistically  p r e c i p i t a t i o n c e l l s and d e v e l o p s h i s  own a n a l y s i s f o r c o n v e c t i v e r a i n s h o w e r s . of  rainfall  and t r a c k .  [Konr78] g i v e s a survey o f a t t e m p t s t o d e s c r i b e the  radar  approach t o d e v e l o p b e t t e r d e s i g n  p a r a m e t e r s which encompass shape,  patterns  However, t h e  t h e s e parameters v a r y from r e g i o n t o r e g i o n , thus  values  although  90  a n a l y s e s have been undertaken f o r s e v e r a l areas o f the States  and Canada, a study which takes  United  i n t o c o n s i d e r a t i o n the  f a c t o r s i n f l u e n c i n g p r e c i p i t a t i o n i n the Vancouver area local  data  for t h i s 5.3  i s necessary  to determine design storm parameters  region.  A p p l i c a t i o n to E n g i n e e r i n g Hydrology - Runoff M o d e l l i n g  The  potential  engineering realized.  over  radar-derived  radar  relatively  new  precipitation  applications  As a data source  traditional  specific  of  hydrology  referenced  advantages  raingauge  records.  i s not without  application  radar  the  will  viewpoint  measurement  alternative.  of  Given  of  the  even  degree These  is  a  very  the  eliminates  the  or  recording  intensive  effort  attractive  of  for  operating  raingauges,  the  f a c i l i t y of the radar system may  the  be  T h i s advantage i s p a r t i c u l a r l y  non-telemetered  need  of  strengths  the high c o s t of i n s t a l l i n g and  where r e a l - t i m e p r o c e s s i n g of the data in  the  data c o l l e c t i o n and management,  rainfall  measurement  this  here.  s i g n i f i c a n t l y cheaper o v e r a l l . important  However,  i t s l i m i t a t i o n s , and  determine  a dense network of telemetered centrallized  fully  measurements o f f e r some d i s t i n c t  and weaknesses are d i s c u s s e d From  yet been  in  spatially  tool  runoff  not  data  simulation,  point  in  has  a p p l i c a b i l i t y of r a d a r - d e r i v e d r a i n f a l l data.  but  using  time  c o m p i l i n g and  is  required,  gauge s i t u a t i o n the consuming  and  radar labour  e n t e r i n g the gauge data -  91  computer c o n t r o l l e d d i g i t a l an  organized,  machine  radar  systems generate  readable  format.  records  In addition,  radar  m e a s u r e m e n t s o b v i a t e t h e n e c e s s i t y o f c o n s i d e r i n g c/auge factors,  in  siting  s u c h a s e x p o s u r e a n d e l e v a t i o n , when u s i n g t h e d a t a .  The  s p a t i a l and temporal  another  forte  of r a d a r - d e r i v e d r a i n f a l l  measurements  are  made  surface  features,  obtained  f o r areas  impractical, addition,  measurement c h a r a c t e r i s t i c s  in  land  the  atmosphere,  as  Because  radar  independent  of  u s e , a n d v e g e t a t i o n , r e a d i n g s may be  f o r which raingauge  such  data.  are  over  the radar data  lakes,  grid  measurements dense  i s evenly  would  be  f o r e s t s , e t c . In  spaced over  the  whole  r e g i o n , e l i m i n a t i n g t h e problems o f a r e a l b i a s i n r e c o r d s , and hence  in  any  simulation  non-uniformities Temporally, shorter  in  than  records  gauge  of  five  d e p e n d i n g on t h e s a m p l i n g As radar  distribution  of  measurements Using  is  f o r as short or  Time i n t e r v a l s  or  minutes  regime  one  locations.  values. ten  of  between  are  typical,  implemented.  discussed i n the previous chapter,  source.  gauge  r a d a r m e a s u r e m e n t s may be o b t a i n e d  periods  successive  the  c a r r i e d o u t u s i n g t h e d a t a , due t o  the accuracy  of the  t h e weak p o i n t s o f t h i s  one o r two r a i n g a u g e s  to calibrate  the  data  radar,  r e s u l t s w i t h an e r r o r o f a b o u t t h i r t y p e r c e n t  may be o b t a i n e d .  It  error  was  pointed  significantly thus  earlier  that  w i t h i n c r e a s i n g l e n g t h of  the radar  long-term,  out  rainfall  continuous  this  decreases  accumulation  period:  d a t a may c u r r e n t l y be b e t t e r s u i t e d t o simulation  than  to  single  event  92  modelling. When viewed as an  operational  f o r engineering  hydrological  data  source  of  precipitation  purposes,,  the e x i s t i n g  SCEPTRE r a d a r has d i s t i n c t s h o r t c o m i n g s . forecasting  models,  such  as  the  For  UBC  i s of  problem  practical  i n large  Watershed Model, t h e  r e s o l u t i o n o f t h e r a d a r i s t o o f i n e : more than  use  data  is  generated  use i n t h e s i m u l a t i o n . A l t h o u g h  this  c o u l d be overcome by lumping t h e v a l u e s i n t o a c o a r s e r  g r i d , t h e l i m i t e d u s e f u l range of measurement total  of  area  rainfall  being  particularly  the  system  precludes  over a l l but a s m a l l p o r t i o n of the  modelled.  susceptible  to  Radar  measurements  coefficients  In  addition,  the  differing  a  found i n  reflectivity  f o r r a i n and snow make t h e use of r a d a r much more  d i f f i c u l t i n r e g i o n s where b o t h r a i n and snow o c c u r . SCEPTRE  are  i n t e r f e r e n c e from topography,  v e r y i m p o r t a n t c o n s i d e r a t i o n g i v e n t h e rugged t e r r a i n B r i t i s h Columbia.  the  radar  could  Thus the  not be e c o n o m i c a l l y j u s t i f i e d s o l e l y on  the b a s i s of p r o v i d i n g  meterological  data  for large  basin  runoff modelling. In t h e c o n t e x t of urban r u n o f f m o d e l l i n g , where t h e b a s i n length  i s o f t e n s m a l l e r than t h e two km square g r i d s p a c i n g ,  the SCEPTRE r a d a r p r o v i d e s a c o a r s e r s p a t i a l would  be  ideal.  At  convective precipitation  this  level  resolution  than  of d e t a i l , h i g h - i n t e n s i t y  dominates as  the  design  criteria.  A l t h o u g h t h e SCEPTRE r a d a r d a t a p r o v i d e s comprehensive s p a t i a l rainfall  i n f o r m a t i o n which  i n c l u d e s measurements of i n t e n s i t y  93  i n the c o n v e c t i v e c e l l s , the r e s o l u t i o n i s not f i n e enough  to  show the e f f e c t of the d i r e c t i o n and v e l o c i t y of c e l l movement on  t h e r u n o f f from the b a s i n .  S i n c e the storm speed i s o f t e n  on the o r d e r of f i f t y k i l o m e t r e s per hour, a c e l l w i l l almost  t h r e e g r i d squares  and may  pass  directly  over  over i t .  the  i n the t e n minutes between samples,  small  basin  without  Thus the temporal  i s a l s o inadequate again,  a  for  most  operational  travel  urban  detected  r e s o l u t i o n of t h i s radar runoff  SCEPTRE  being  radar  modelling.  cannot  be  Here  justified  s o l e l y on the b a s i s of b e i n g an e n g i n e e r i n g measurement t o o l . 5.4  E n g i n e e r i n g use of R a d a r - D e r i v e d  Runoff  P r e c i p i t a t i o n Data: Urban  Case Study  D e s p i t e the f a c t t h a t the SCEPTRE from  deficiencies  spatial  which  rainfall  principle  of  system  suffers  l i m i t i t s u s e f u l n e s s as a source  data  using  radar  for  urban  runoff  radar-derived  modelling,  measurements  in  of the  runoff  s i m u l a t i o n s i s sound.  S i n c e the c h a r a c t e r i s t i c s of the  basin  being  in  input  should  modelled vary  Engineers  vary  likewise  to  experienced  two-dimensions, obtain  accurate  rainfall" recognize well  when  spatially,  may  be  [Hube8l].  runoff  values.  i n urban r u n o f f m o d e l l i n g have a d v i s e d  t h a t "even f o r s m a l l c a t c h m e n t s , r u n o f f and predictions  the r a i n f a l l  very  consequent  model  s e n s i t i v e to s p a t i a l variations in  However,  these  same  authors  fail  to  t h a t t h i s v a r i a b i l i t y extends t o f r o n t a l systems as they as  state might  that  " i f the  be e x p e c t e d  rainfall  is  uniform  from c y c l o n i c storms,  these  94  s p a t i a l c o n s i d e r a t i o n s a r e not as  important."  To i n v e s t i g a t e the s e n s i t i v i t y pf an urban spatial  and  temporal  catchment  to  v a r i a t i o n s i n r a i n f a l l , a catchment i n  the F a i r v i e w a r e a of s o u t h e a s t Vancouver was m o d e l l e d w i t h the Storm Water Management radar  data  as  r e l a t i v e l y new sewers  Model  using  precipitation  the  Abbotsford  input.  The  s u b d i v i s i o n with separate  SCEPTRE  catchment  storm  and  is  sanitary  (much of Vancouver i s on combined sewer s y s t e m s ) .  long,  narrow  basin  is  oriented  with  the  a  long  The axis  a p p r o x i m a t e l y n o r t h - s o u t h , and d r a i n s i n t o the F r a s e r R i v e r a t the  south  end  (fig.  t w e l v e subcatchments. coefficients  were  5.1).  The b a s i n was d i s c r e t i z e d  Standard adopted  and  roughness  f o r the s i m u l a t i o n [SWMM76].  r u n o f f b l o c k of the model was hydrograph  infiltration  into  used  to  calculate  a t the F r a s e r R i v e r o u t f a l l .  an  The  outlet  No q u a l i t y m o d e l l i n g  was i n c l u d e d . P r e c i p i t a t i o n d a t a i n p u t was SCEPTRE  radar  for  the  catchment spanned two three  most  remainder  i n an  subcatchments squares was  December  radar  northerly  as  the  i n which they were s i t u a t e d .  taken  as  precipitation hydrograph  (fig.  the  same  value  measurements: 5.2)  is  as ten  grid  in  Input  the  storm  measurement  one.  taken  from  1980  subcatchments  adjacent were  taken  one  Abbotsford event.  The  squares:  the  square and  the  hyetographs  for  the  v a l u e s f o r the r a d a r g r i d The model time the  interval  minutes.  indicative  of  a  The basin  increment between outlet with  a  95  F i g u r e 5.1 relatively  fast  - Map of F r a s e r v i e w catchment  response  time  -  in  this  case due t o the  c o m p a r a t i v e l y s t e e p s l o p e s i n p o r t i o n s of t h e b a s i n . To determine simulation  t h e s p a t i a l s e n s i t i v i t y of  the  minor d i f f e r e n c e s . S i m i l a r r e s u l t s  actual  track  was  track.  direction  the  was r e p e a t e d w i t h t h e storm d i r e c t i o n r e v e r s e d .  comparison of t h e r e s u l t i n g hydrographs ( f i g .  storm  basin,  and  were  5.3)  obtained  A  shows o n l y when  the  s h i f t e d two k i l o m e t r e s e a s t and west of i t s This  path  analysis are  seems  to  not v e r y c r i t i c a l  imply  that  storm  factors i n runoff  96  e>  ** I  0.0  FRASERVIEW i  i  20.0  i  1  1  40.0  CATCHMENT 1  60.0  •-  ..  1—-i 1  1  80.0  100.0  OUTLET 1  1  120.0  TIME (MINUTES) (X10  1  HYDROGRAPH  1  1  U0.O  1  1  1  160.0  1  1B0.O  r  200.0  ) .  F i g u r e 5.2 - SWMM o u t l e t hydrograph f o r t h e F r a s e r v i e w catchment, December 1980 storm m o d e l l i n g , and hence i n storm sewer d e s i g n .  T h i s i s somewhat  contrary  a  to  what  was  expected  p r e c i p i t a t i o n p a t t e r n s themselves. may  i n part  from  study  T h i s l a c k of  of t h e  sensistivity  be due t o t h e s p a t i a l r e s o l u t i o n l i m i t a t i o n s of  t h e r a d a r - s i n c e most of t h e b a s i n l i e s w i t h i n one r a d a r g r i d s q u a r e , t h e model p l a c e s t h e same r a i n f a l l over  t h e most  of  the b a s i n a r e a a t t h e same t i m e , and thus t h e e f f e c t s of storm motion  a r e n o t seen.  Therefore  the r e s u l t s  may best be  97  FRASERVIEW "I  I  I  I  I  CATCHMENT I  I  I  1  1  OUTLET 1  1  1  HYDROGRAPH 1  1  1  1  1  r-  CORRECT DIRECTION REVERSED DIRECTION  o -9  L  0.0  7C.0  Aj. i «C.O  1  60.0  80.0  lOOJO  120.0  TIME (MINUTES) (X10 ) 1  UO 0  16C.C  180.0  700.0  F i g u r e 5 . 3 - Comparison o f SWMM o u t l e t hydrographs f o r normal and r e v e r s e d storm d i r e c t i o n s described as i n c o n c l u s i v e sensitivity:  higher  as  spatial  f a r as demonstrating  spatial  r e s o l u t i o n r a d a r d a t a i s needed  b e f o r e a g e n e r a l c o n c l u s i o n may be made. The t e m p o r a l s e n s i t i v i t y o f t h e model was demonstrated by a p p l y i n g e q u i v a l e n t h o u r l y p r e c i p i t a t i o n d a t a from t h e n e a r e s t r e c o r d i n g raingauge,  n i n e k i l o m e t r e s away, t o t h e same b a s i n .  The t o t a l volume of t h i s  rainfall  was comparable  t o that  98  obtained  from  the radar.  hydrographs ( f i g .  A  comparison  of  the resulting  5 . 4 ) c l e a r l y shows t h e inadequacy  of t h e  FRASERVIEW CATCHMENT OUTLET HYDROGRAPH  20.0  40.0  60.0  80.0  100.0  UO.O  120.0  TIME (MINUTES) (X10  1  160 0  180 C  70C 0  )  F i g u r e 5 . 4 - Comparison of SWMM hydrographs from t e n minute r a d a r and e q u i v a l e n t h o u r l y gauge d a t a hourly  data  i n t h i s model.  The peak r u n o f f from t h e h o u r l y  d a t a u n d e r e s t i m a t e s t h a t from t h e r a d a r d a t a by three,  and  although  the timings  a  factor  of  of t h e o t h e r r u n o f f peaks  agree i n b o t h h y d r o g r a p h s , a l l t h o s e from  the hourly  values  99  show  lower f l o w s .  T h i s d r a m a t i c d i f f e r e n c e i s l a r g e l y due t o  the a v e r a g i n g of the peak hourly  precipitation  intensities  i n the  r e c o r d s , r e d u c i n g t h e maximum v a l u e s , which when i n p u t  t o t h e model, produce more i n f i l t r a t i o n and hence l e s s  direct  runoff. As was noted e a r l i e r , r a i n f a l l a c c u m u l a t i o n s d e r i v e d from spatial  precipitation  data  by  integrating  periodic  measurements w i l l be g r o s s l y i n e r r o r i f t h e storm v e l o c i t y i s such t h a t c e l l movement between samples i s g r e a t e r grid  spacing.  suitability  This  one f a c t o r i n d e t e r m i n i n g t h e  Spatial resolution c r i t e r i a are a  necessary temporal r e s o l u t i o n time.  But  the  i s established  combination  of  c r i t i c a l , and depends on t h e v e l o c i t y of This  relationship  may  be  seen  v e r s u s temporal r e s o l u t i o n of 5.5)  in  by  the  the  the two  storm  The basin  i s also system.  the p l o t of the s p a t i a l  rainfall  data  sources ( f i g .  The l i n e r e p r e s e n t s matching r e s o l u t i o n s under t h e storm  velocity criteria.  The b a s i n s i z e and response time  would be shown a s h o r i z o n t a l and v e r t i c a l l i n e s Thus  function  t h e s i z e of t h e b a s i n and t h e type of model employed.  response  one  of a d a t a base of s p a t i a l p r e c i p i t a t i o n r e c o r d s t o  runoff modelling. of  i s also  than  the  minimum  spatial  and  criteria  respectively.  temporal r e s o l u t i o n  required  c o r r e s p o n d s t o t h e i n t e r s e c t i o n of t h e d i a g o n a l l i n e w i t h  the  t i m e or space c r i t e r i a  l i n e s which l i e s c l o s e s t t o t h e o r i g i n .  Alternatively,  a  given  s o u r c e of s p a t i a l r a i n f a l l d a t a w i t h  known r e s o l u t i o n l i m i t a t i o n s , t h e type of b a s i n and is  best  suited  f o r may be d e t e r m i n e d .  model i t  As can be seen, t h e  100  SPATIAL/TEMPORAL  3  5 7 »•  RESOLUTION  3  5 7 10"  3  O F RAINFALL  5 7 K>»  MEASUREMENTS  5 7 10*  3  3  5 7 KJ'  TIME BETWEEN RECORDS (MINUTES)  F i g u r e 5.5 - S p a t i a l / t e m p o r a l r e s o l u t i o n r e q u i r e m e n t s of r a i n f a l l d a t a - storm v e l o c i t y 60 kmh radar data l i e s resolution  below  the l i n e ,  indicating  i s the c r i t i c a l d e f i c i e n c y .  that  temporal  S i m i l a r l y , the d a i l y  gauge d a t a , when taken a s a s p a t i a l network  of o b s e r v a t i o n s ,  i s i n a d e q u a t e f o r m o d e l l i n g a l l but t h e l a r g e s t of b a s i n s . I n an  urban  runoff  modelling  s i t u a t i o n , a s p a t i a l c r i t e r i a of  h a l f a k i l o m e t r e r e s o l u t i o n would second  temporal r e s o l u t i o n .  then  also  require  thirty  C o o r d i n a t e d measurements on t h i s  t i m e s c a l e would be d i f f i c u l t t o o b t a i n from r a i n g a u g e s , but a  101  r a d a r system d e d i c a t e d t o h i g h r e s o l u t i o n measurement over urban a r e a c o u l d f u l f i l l these The  an  requirements.  i n c r e a s i n g c o s t of water r e s o u r c e systems i s f o r c i n g  e n g i n e e r s t o undertake  more  extensive  c o m p l i c a t e d m o d e l l i n g procedures practices.  These  complex  analyses  using  t o avoid expensive models  require  extensive  base,  storm which t a k e s i n t o account  t h e e f f e c t s of l o c a l phenomena,  produce  viable results.  network i s inadequate while  a  distinct  resolution  realistic  design  The e x i s t i n g p r e c i p i t a t i o n gauge  f o r t h i s p u r p o s e , and the SCEPTRE r a d a r ,  improvement  over  a  overdesign  h i s t o r i c a l p r e c i p i t a t i o n data  to  or  an  more  the  point  in  gauge  spatial  and  temporal  d a t a , has drawbacks which  l i m i t i t s u s e f u l n e s s as a source of e n g i n e e r i n g  preciptiation  data. 5.5  Recommendations f o r Improvements t o the SCEPTRE Radar and  Data A r c h i v e and R e t r i e v a l  There  are  relatively  easy  a  number to  of  implement  improvements  a c c e s s t o the d a t a  large  investment  and  would  i t provides.  maintenance  Given  the  investment  and  the  c o s t s f o r such a  f a c i l i t y , more use of t h e d a t a would p r o v i d e a g r e a t e r on  be  on t h e SCEPTRE r a d a r t o a l l o w  more widespread capital  which  return  j u s t i f y the c o n t i n u a t i o n of the data  archive. The  c u r r e n t p r a c t i c e of m a i n t a i n i n g a complete a r c h i v e of  p r e c i p i t a t i o n data may have t o be abandoned  in  favour  of  a  102  procedure  which  Certainly,  the  applications  saves vast  archived  The  would  only  storm  more  for  much  money the  events.  engineering major  hydrology  storms,  r e d u c t i o n i n the amount of  allow  of  of  data  p r o c e s s i n g and a n a l y s i s of information  significant  majority  require  complete r e c o r d .  only  data  not  a  to  be  and e f f o r t t o be spent  important  records,  on  yielding  more v a l u e t o the e n g i n e e r i n g community  than i s c u r r e n t l y p r o v i d e d by the complete r a d a r d a t a a r c h i v e . There a r e s e v e r a l ways i n which information  the  real-time  rainfall  c o u l d be made a v a i l a b l e t o the p u b l i c which would  r e q u i r e v e r y l i t t l e equipment or s o f t w a r e t o be added system.  The  first  is  to  install  a  low  to  speed,  the  serial  communication d i a l - u p f a c i l i t y t o a l l o w a user w i t h a computer and a modem c o n n e c t i o n t o o b t a i n d i g i t a l r a i n f a l l and  accumulations  for  a  r e g i o n around the r a d a r s i m i l a r i n  e x t e n t t o t h a t chosen i n t h i s s t u d y .  For example, by  a subset of the coverage r e g i o n which populous a r e a of southwestern most  of  the  intensities  contains  most  choosing of  the  B r i t i s h Columbia w h i l e e x c l u d i n g  a r e a s o c c l u d e d by mountains, one complete image  d a t a - s e t c o u l d t r a n s m i t t e d i n about t h r e e minutes a t 300 baud. The a v a i l a b i l i t y of s m a l l , i n e x p e n s i v e computer  systems  with  communications i n t e r f a c e c a p a b i l i t y makes t h i s p r a c t i c a l f o r a wide  variety  of u s e r s of p r e c i p i t a t i o n d a t a .  would be  of  great  agencies  in  the  use area,  to such  many  companies  allow  them  to  make  and  government  as those o p e r a t i n g r e s e r v o i r s ,  storm sewer c o n t r o l f a c i l i t i e s , and sewage to  Such a s e r v i c e  treatment  plants,  d e c i s i o n s based on g e n e r a l or  local  103  accurate,  up-to-date  estimates  from  the  new  local  Telidon  offers  the  information  rather  than  weather f o r e c a s t s .  interactive  opportunity  provide  retrieval  these  radar  p a t t e r n s t o a wide range o f p e o p l e a t a v e r y Telidon  data  base  could  be  updated  p r e c i p i t a t i o n map on an h o u r l y b a s i s .  low  with  then  the  rainfall  a  new  The colour  This information  The r e t u r n s t o t h e community would  could  etc.  have a c c e s s t o more r e a l i s t i c s h o r t - t e r m  information.  system  cost.  be of u n t o l d use t o many s m a l l businessmen, f a r m e r s , would  ' on  In a s i m i l a r v e i n ,  information  to  based  who  rainfall  amply  repay  modest investment i n v o l v e d , and p r o v i d e j u s t i f i c a t i o n f o r  the c o n t i n u e d  o p e r a t i o n and improvement of t h e system.  B e f o r e wider use rainfall  acceptance  target  software  the  radar-derived  eliminate  the  are  necessary.  by  echos  o f f nearby  need f o r t h e o v e r l a y mask.  the image p r e s e n t a t i o n and obscure measurments a r e p o s s i b l e .  the images be f r e e construction.  The  addition  of  i n d i c a t o r p r o c e s s i n g would remove t h e s p u r i o u s  r a i n f a l l v a l u e s caused  valid  of  i n f o r m a t i o n i s p o s s i b l e , enhancements t o t h e SCEPTRE  data processing moving  and  of  Again,  ring by  some  mountains  and  These d e t r a c t from areas  within  which  A second requirement i s t h a t  artifacts  caused  during  CAPPI  enhancing the e x i s t i n g s o f t w a r e i t  s h o u l d be p o s s i b l e t o e l i m i n a t e t h i s e r r o r  source.  Many s m a l l e n g i n e e r i n g c o n s u l t a n t s do not have a c c e s s  to  a computer s u p p o r t i n g a 9-track tape d r i v e , which i s c u r r e n t l y a  p r e r e q u i s i t e t o r e a d i n g AES s u p p l i e d magnetic t a p e s .  These  104  companies o f t e n do own o r would be w i l l i n g t o purchase minicomputer mass  o r microcomputer, which  storage.  As  which o f t e n makes data,  AES  rainfall  historic to  magnetic t a p e s . operating  service  practical  should  alternative  a  data  of  making  available  the more  floppy  disks for  t o t h e e n g i n e e r i n g community,  use  consider  uses  a small  historic  precipitation  b o t h r a d a r and raingauge on  this  medium  e x p e n s i v e and l e s s e a s i l y  U s i n g a s t a n d a r d format  on  widely  as  an  accessed accepted  systems such as CPM, UNIX, e t c . , t h i s s e r v i c e would  g r e a t l y enhance  accessibility  to  the  data  for a  minimal  i n c r e a s e d c o s t t o AES. By  adding  a  small  amount  of  e x t r a c a p a b i l i t y t o the  SCEPTRE system, a r c h i v i n g o n l y s i g n i f i c a n t storm providing  events,  p r e c i p i t a t i o n d a t a on more w i d e l y u s e a b l e medium i n  s t a n d a r d f o r m a t s , AES can v a s t l y improve the a c c e s s meteorological  data.  These  improvements  b e n e f i t t o t h e e n g i n e e r i n g community, and public,  and  compounding  meteolological additional cost.  the  return  data-collection  on  to  would be of g r e a t indirectly  investment  network  their  for  t o the from  a  the  minimal  105  CHAPTER VI  CONCLUSIONS The development of a n a l y t i c a l water require  r e s o u r c e models which  a c c u r a t e and comprehensive p r e c i p i t a t i o n d a t a has n o t  been accompanied by a p p r o p r i a t e improvements i n data  bases.  Radar measurement of r a i n f a l l  o f f e r s t h e promise spatial  and  of  temporal  providing  data  resolution  precipitation  i s a method which  with  the  necessary  a t a reasonable c o s t .  The  e x i s t e n c e of a major o p e r a t i o n a l r a d a r system and d a t a a r c h i v e would n a t u r a l l y suggest t h e u s e f u l a p p l i c a t i o n of t h i s  data.  T h i s study r e v e a l e d t h a t , w h i l e i t has c o n s i d e r a b l e p o t e n t i a l , the c a p a b i l i t i e s of t h e p r e s e n t SCEPTRE system do not p r o p e r l y meet e n g i n e e r i n g h y d r o l o g y needs. However, some s i g n i f i c a n t b e n e f i t s a r e s t i l l The  spatially-referenced  insight into  the  SCEPTRE  structure  and  radar  data  movement  attainable. provides  of  new  precipitation  p a t t e r n s over t h e Vancouver a r e a which i s p r e s e n t l y i m p o s s i b l e to  obtain  from  any  other  source.  Some  b e n e f i t s o f t h e SCEPTRE d a t a were demonstrated imagery  was  presented  in a  colour  of t h e p o t e n t i a l when t h e  radar  g r a p h i c a l format  which  a l l o w e d t h e v a s t q u a n t i t y of r a i n f a l l  information provided  the  The s e n s i t i v i t y of urban  r a d a r t o be e a s i l y a s s i m i l a t e d .  by  catchments t o s p a t i a l and temporal v a r i a t i o n s i n p r e c i p i t a t i o n was i n v e s t i g a t e d by a p p l y i n g t h e r a d a r d a t a t o an  engineering  runoff  for spatial  model.  Time-space  resolution  criteria  106  p r e c i p i t a t i o n d a t a employed i n determined  from  an  water  examination  of  resources  models  the d e f i c i e n c i e s  were of t h e  SCEPTRE d a t a . Precipitation hydrometeorological capabilities  and  source  radar  of  radar  is  data. inherent  This  a  viable study  limitations  precipitation  data.  has of  source  of  explored  the  one From  o b t a i n e d , recommendations f o r improvements t o  the  enhance  to  i t s suitability  h y d r o l o g y have been  for applications  suggested.  operational the  results  system  to  engineering  107  REFERENCES AND  BIBLIOGRAPHY  Ackerman, B., 1959: " O r o g r a p h i c - C o n v e c t i v e P r e c i p i t a t i o n as Revealed by Radar", P h y s i c s of P r e c i p i t a t i o n , American G e o p h y s i c a l U n i o n , Washington, D.C, pp. 79-85. [AES 81] 1981: F l o o d Hydrology Guide f o r Canada: H y d r o m e t e o r o l o q i c a l T e c h n i q u e s , W. I . P u g s l e y , e d i t o r , Atmospheric Environment S e r v i c e P u b l i c a t i o n CL13-81, Downsview, O n t a r i o . [Aoya78] A o y a g i , J . , 1978: "Ground C l u t t e r R e j e c t i o n by MTI Weather Radar", P r e p r i n t s , 18th Conference on Radar M e t e o r o l o g y ( A t l a n t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 358-363. [ A t l a 5 l ] A t l a s , D. and Banks, H.C, 1951: "The I n t e r p r e t a t i o n of Microwave R e f l e c t i o n s from R a i n f a l l " , J o u r n a l of M e t e o r o l o g y , v o l . 8, pp. 271-282. [ A u s t 5 9 ] A u s t i n , P.M., 1959: " M i c r o s t r u c t u r e of Storms as D e s c r i b e d by Q u a n t i t a t i v e Radar Data", P h y s i c s of P r e c i p i t a t i o n , American G e o p h y s i c a l U n i o n , Washington D.C, pp. 86-93. [Aust80a] A u s t i n , G.L., 1980: "The Use of Radar Data and S a t e l l i t e Data i n Hydrometeorology", P r e p r i n t s , Atmospheric Environment S e r v i c e s Workshop, (Downsview, O n t a r i o ) , November 1980. [Aust80b] A u s t i n , P.M., 1980: "Some Comparisons of R a i n f a l l Amounts Measured by Radar and w i t h Raingauges", P r e p r i n t s , 1 9 t h Conference on Radar M e t e o r o l o g y (Miami Beach), American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 431-437. [ B a r r 7 6 ] B a r r y , R.G. and C h o r l e y , R.J., 1976: Atmosphere, Weather, and C l i m a t e , Methuen, S u f f o l k , Great Britain. [ B a t t 5 9 ] B a t t a n , L . J . , 1959: Radar M e t e o r o l o g y , U n i v e r s i t y of Chicago P r e s s , Chicago. [ B e s t 5 0 ] B e s t , A . C , 1950: "The S i z e D i s t r i b u t i o n of R a i n d r o p s " , Q u a r t e r l y J o u r n a l of the R o y a l M e t e o r o l o g i c a l S o c i e t y , v o l . 76, pp. 16-30. [ B l a c 7 2 ] B l a c k n e r , R.H. and Duda, R.O., 1972: " A p p l i c a t i o n of P a t t e r n R e c o g n i t i o n Techniques t o D i g i t a l Radar D a t a " , P r e p r i n t s , 15th Radar M e t e o r o l o g y Conference (Champaign-Urbana), American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 138-143.  108  [Brad78] Brady, P . J . , S c h r o e d e r , 3.3., and P o e l l o t , M.R., 1978: "Automatic I d e n t i f i c a t i o n and T r a c k i n g of Radar Echoes i n HIPLEX", P r e p r i n t s , 18th Conference on Radar M e t e o r o l o g y ( A t l a n t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 139-143. B r u c e , J.P. and C l a r k , R.H., 1966: I n t r o d u c t i o n t o Hydrometeorology, Pergamon P r e s s , O x f o r d . [Chow64] Chow, V.T., e d i t o r , 1964: Handbook of A p p l i e d H y d r o l o g y , M c G r a w - H i l l , New York. [ C r o z 7 5 ] C r o z i e r , C.L., 1975: "A C-Band M e t e o r o l o g i c a l Radar System f o r Q u a n t i t a t i v e Measurement and C l o u d P h y s i c s R e s e a r c h " , Canadian M e t e o r o l o g i c a l Memoirs, No. 30, Atmospheric Environment S e r v i c e s Canada. [CDC  79a] 1979: System f o r Constant E l e v a t i o n P r e c i p i t a t i o n T r a n s m i s s i o n and R e c o r d i n g (SCEPTRE), Hardware Manual, v o l . 1, Computing D e v i c e s Company.  [CDC  79b]  1979: System f o r Constant E l e v a t i o n P r e c i p i t a t i o n T r a n s m i s s i o n and R e c o r d i n g (SCEPTRE), T e c h n i c a l U s e r s Manual, Computing D e v i c e s Company.  [ D r u f 7 6 ] D r u f u c a , G. and P a w l i n a , A., 1976: "Some S t a t i s t i c s of Radar P r e c i p i t a t i o n P a t t e r n s " , P r e p r i n t s , 17th Conference on Radar M e t e o r o l o g y ( S e a t t l e ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 438-441. [ E a g l 7 0 ] E a g l e s o n , P.S., New York.  1970: Dynamic H y d r o l o g y , M c G r a w - H i l l ,  F l a n d e r s , A.F., 1969: H y d r o l o g i c a l Requirements f o r Weather Radar D a t a , Report No. 9, World M e t e o r o l o g i c a l O r g a n i z a t i o n , Geneva. [ F o l e 8 2 ] F o l e y , J.D. and Van Dam, A., 1982: Fundamentals I n t e r a c t i v e Computer G r a p h i c s , Addison-Wesley, Reading, M a s s a c h u s e t t s .  of  [Geot76] G e o t i s , S.G. and S i l v e r , W.M., 1976: "An E v a l u a t i o n of Techniques f o r A u t o m a t i c Ground Echo R e j e c t i o n " , P r e p r i n t s , 17th Conference on Radar M e t e o r o l o g y ( S e a t t l e ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 448-452. [ G l o v 7 2 ] G l o v e r , K.M., 1972: "A P r e c i s i o n V i d e o I n t e g r a t o r " , P r e p r i n t s , 15th Weather Radar Conference (ChampaignUrbana), American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 193-197. G o r r i e , J.E. and Kouwen, N., 1977: " H y d r o l o g i c a l A p p l i c a t i o n s of C a l i b r a t e d Radar P r e c i p i t a t i o n  109  Measurements", P r e p r i n t s , 2nd Conference on Hydrometeorology ( T o r o n t o ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 272-279. [Gunn58] Gunn, K.L.S. and M a r s h a l l , J.S., 1958: "The D i s t r i b u t i o n w i t h S i z e of Aggregate S n o w f l a k e s " , J o u r n a l of M e t e o r o l o g y , v o l . 15, pp. 452-461. [Hans82] Hanssen, A . J . , 1982: Correspondence  w i t h the A u t h o r .  [Hay 73] Hay, J.E. and Oke, T.R., 1973: The C l i m a t e of Vancouver, T a n t a l u s R e s e a r c h , Vancouver. [ H i t s 5 4 ] H i t s c h f e l d , W. and Bordan, J . , 1954: " E r r o r s I n h e r e n t i n the Radar Measurement of R a i n f a l l a t A t t e n u a t i n g Wavelengths", J o u r n a l of M e t e o r o l o g y , v o l . 11, pp. 58-67. [Hobb79] Hobbs, P.V. and B i s w a s , K.R., 1979: "The C e l l u l a r S t r u c t u r e of Narrow C o l d - F r o n t a l Rainbands", Q u a r t e r l y J o u r n a l of t h e R o y a l M e t e o r o l o g i c a l S o c i e t y , v o l . 105, no. 445, pp. 723-727. [Hogg78] Hogg, W.D., 1978: " Q u a l i t y C o n t r o l of an A r c h i v e of D i g i t a l Radar D a t a " , P r e p r i n t s , 18th Conference on Radar M e t e o r o l o g y ( A t l a n t a ) , American M e t e o r o l o g i c a l • S o c i e t y , B o s t o n , pp. 150-154. [ H o r i 8 0 ] H o r i t a , M., 1980: A b b o t s f o r d SCEPTRE Radar, T e c h n i c a l Note No. 14, I n t e r n a l Atmospheric Environment S e r v i c e s Canada R e p o r t .  PWC  [Houz76] Houze, R.A., B i s w a s , K.R., and D a v i s , W.M., 1976: "Mesoscale Rainbands i n E x t r a t r o p i c a l C y c l o n e s " , Monthly Weather Review, American M e t e o r o l o g i c a l S o c i e t y , v o l . 104, pp. 868-878. [Hube8l] Huber, W.C., Heaney, J.P., N i x , S . J . , D i c k i n s o n , R.E., and Polmann, D.J., 1981: Storm Water Management Model User's Manual, V e r s i o n I I I , Department of E n v i r o n m e n t a l E n g i n e e r i n g S c i e n c e s , U n i v e r s i t y of Florida. [ H u f f 7 8 ] H u f f , F.A. and Towery, N.G., 1978: " U t i l i z a t i o n of Radar i n O p e r a t i o n of Urban H y d r o l o g i c Systems", P r e p r i n t s , 18th C o n f e r e n c e on Radar M e t e o r o l o g y ( A t l a n t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 437-441. [ H u f f 8 0 ] H u f f , F.A., Changnon, S.A., and V o g e l , J . L . , 1980: " C o n v e c t i v e R a i n f a l l M o n i t o r i n g and F o r e c a s t i n g System f o r an Urban A r e a " , P r e p r i n t s , 19th Conference on Radar M e t e o r o l o g y (Miami" B e a c h ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 56-61. «  110  [Hump79a] Humphries, R.G. and Barge, B.L., 1979: "Weather Radar R a i n f a l l Measurements i n a C o o l C l i m a t e " , P r e p r i n t s , 3 r d Conference on Hydrometeoroloqy ( B o g a t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 58-61. [Hump79b] Humphries, R.G. and Barge, B.L., 1979: "Weather Radar R a i n f a l l Measurements f o r O p e r a t i o n a l Streamflow F o r e c a s t i n g " , P r e p r i n t s , 3 r d Conference on Hydrometeoroloqy ( B o g a t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 62-66. James, P.K., Browning, K.A., Gunawardana, R., and Edwards, J.A., 1978: "A Case of L i n e C o n v e c t i o n Observed by Radar u s i n g a H i g h R e s o l u t i o n C o l o u r D i s p l a y " , Weather, v o l . 33, pp. 212-215. James, P.K. and Browning, K.A., 1979: "Mesoscale S t r u c t u r e of L i n e C o n v e c t i o n a t S u r f a c e C o l d F r o n t s " , Q u a r t e r l y J o u r n a l of t h e R o y a l M e t e o r o l o g i c a l S o c i e t y , v o l . 105, pp. 371-382. [Jame8l] James, W. and R o b i n s o n , M., 1 9 8 1 : P o t e n t i a l Coo r d i n a t e d M u l t i p r o c e s s i n g System f o T F i e l d Data A c q u i s i t i o n and R e a l - t i m e C o n t r o l of Urban D r a i n a g e i n H a m i l t o n , Dep't of C i v i l E n g i n e e r i n g , McMaster U n i v e r s i y , Hamilton. [Jone55] J o n e s , D.M.A., 1955: "3-cm and 10-cm Wavelength R a d i a t i o n Back S c a t t e r from R a i n " , P r o c e e d i n g s , F i f t h Weather Radar Conference (Ashbury P a r k ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 281-285. K e s s l e r , E. and W i l k , K.E., 1968: Radar Measurement of P r e c i p i t a t i o n f o r H y d r o l o g i c a l Purposes, Report No. 5, World M e t e o r o l o g i c a l O r g a n i z a t i o n , Geneva. [Koda80] K o d a i r a , N., 1980: "Radar Wave A t t e n u a t i o n by Radome Covered w i t h Water F i l m " , P r e p r i n t s , 19th Conference on Radar M e t e o r o l o g y (Miami B e a c h ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 90-91. {Konr78] Konrad, T.G., 1978: " S t a t i s t i c a l Models of Summer Rainshowers D e r i v e d from F i n e - S c a l e Radar O b s e r v a t i o n s " , J o u r n a l of A p p l i e d M e t e o r o l o g y , v o l . 17, n o . 2, pp. 171-188. [Kore78] Koren, V . I . , 1978: "Use of Radar P r e c i p i t a t i o n Measurements f o r F l a s h F l o o d F o r e c a s t i n g " , S o v i e t H y d r o l o g y : S e l e c t e d P a p e r s , v o l . 17, no. 3. pp. 239245. [Mars48] M a r s h a l l , J . S . and Palmer, W.M.,  1948: "The  111  D i s t r i b u t i o n of Raindrops with S i z e " , J o u r n a l of M e t e o r o l o g y , v o l . 5, pp. 165-166. Newman, M.J., 1976: An Example of t h e E f f e c t of Orography on a S q u a l l L i n e , T e c h n i c a l Memorandum No. 832, Atmospheric Environment S e r v i c e , Downsview, Ontario. [Orms72] Ormsby, J.F.A., 1972: "Some R e s u l t s o f A t t e n u a t i o n Compensation A n a l y s i s " , P r e p r i n t s , 15th Radar M e t e o r o l o g y Conference (Champaign-Urbana), American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 144-148. [ O x f o 5 l ] 1951: The C o n c i s e O x f o r d D i c t i o n a r y , C l a r e n d o n Oxford.  Press,  [Prob62] P r o b e r t - J o n e s , J.R., 1962: "The Radar E q u a t i o n i n M e t e o r o l o g y " , Q u a r t e r l y J o u r n a l of t h e R o y a l M e t e o r o l o g i c a l S o c i e t y , v o l . 88, pp. 485-495. [ S a f f 7 8 ] S a f f l e , R.E. and Green, D.R., 1978: "The R o l e of Radar i n the F l a s h F l o o d Watch Warning System: Johnstown Examined", P r e p r i n t s , 18th Conference on Radar M e t e o r o l o g y ( A t l a n t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 468-473. [ S a u v 8 l ] Sauvageau, R., 1981: Report on AES O p e r a t i o n a l Radar Systems, U n p u b l i s h e d Atmospheric Environment S e r v i c e s Canada R e p o r t . Sengupta, S., S m i t h , P.L., D e n n i s , A.S., and Doneaud, A.A., 1980: "Comparing t h e R e g r e s s i o n R e l a t i o n s h i p s Between Radar and Gage R a i n f a l l E s t i m a t e s " , P r e p r i n t s , 19th Conference on Radar M e t e o r o l o g y (Miami Beach), American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 461-466. S h t i f t e r , S., 1981: A K i n e m a t i c Storm Model of Urban D r a i n a g e D e s i g n , Master of E n g i n e e r i n g T h e s i s , MacMaster U n i v e r s i t y . [Smit72] S m i t h , P.L., 1972: " S i t i n g C o n s i d e r a t i n s f o r Weather Radar", P r e p r i n t s . 15th Weather Radar Conference (Champaign-Urbana), American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 99-100. [SWMM76] 1976: Notes, Storm Water Management Model Workshop ( T o r o n t o ) , October 1976, Canada-Ontario Agreement on G r e a t Lakes Water Q u a l i t y , Conference P r o c e e d i n g s No. 4. [Tate78] T a t e h i r a , R. and S h i m i z u , T., 1978: " I n t e n s i t y Measurement o f P r e c i p i t a t i o n Echo Superposed on Ground C l u t t e r - A New A u t o m a t i c Technique f o r Ground  112  C l u t t e r R e j e c t i o n " , P r e p r i n t s , 18th Conference on Radar M e t e o r o l o g y ( A t l a n t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 364-3.69. [Try 72] T r y , E.F„, 1972: "Remoting of CAPPI P i c t u r e s by Computer", P r e p r i n t s , 15th Radar M e t e o r o l o g y Conference (Champaign-Urbana), American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 189-192. Viessman, W., Knapp, J.W., L e w i s , G.L., and Harbaugh, T.E., 1977: I n t r o d u c t i o n t o H y d r o l o g y , Harper & Row, New Y o r k . [Voge80] V o g e l , J . J . , 1980: "Real Time Measurement of C o n v e c t i v e P r e c i p i t a t i o n Over an Urban A r e a " , P r o c e e d i n g s of t h e O x f o r d Symposium on H y d r o l o g i c a l F o r e c a s t i n g , A p r i l 1980, IAHS P u b l i c a t i o n No. 129, pp. 95-102. [Weib76] W e i b l e , M.L. and Sirmans, D., 1976: " S i m u l a t i o n of A t t e n u a t i o n by R a i n f a l l a t a Wavelength of 5 cm", P r e p r i n t s , 17th Conference on Radar M e t e o r o l o g y ( S e a t t l e ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 75-78. [Wexl48] Wexler, R., 1948: " R a i n I n t e n s i t i e s by Radar", J o u r n a l of M e t e o r o l o g y , v o l . 5, pp. 171-173. [ W i l l 7 3 ] W i l l i a m s , A., 1.973: The Use of Radar Imagery i n C l i m a t o l o g i c a l R e s e a r c h , Resource Paper No. 21, Commission on C o l l e g e Geography, Washington, D.C. [ W i l s 7 8 ] W i l s o n , J.W., 1978: " O b s e r v a t i o n s of Radome T r a n s m i s s i o n L o s s e s a t 5 cm Wavelengths", P r e p r i n t s , 18th Conference on Radar M e t e o r o l o g y ( A t l a n t a ) , American M e t e o r o l o g i c a l S o c i e t y , B o s t o n , pp. 288-291. [ W i l s 7 9 ] W i l s o n , J.W. and Brandes, E.A., 1979: "Radar Measurement of R a i n f a l l - A Summary", B u l l e t i n of t h e American M e t e o r o l o g i c a l S o c i e t y , v o l . 60, no. 9, pp. 1048-1058.  113  APPENDIX A SCEPTRE Radar Measurement A l t i t u d e s C o r r e c t e d f o r E a r t h C u r v a t u r e and S t a n d a r d Beam R e f r a c t i o n  SCEPTRE R a d a r Beam M e a s u r e m e n t  Altitude (Corrected  Range (metres)  f o r Standard  Beam R e f r a c t i o n a n d E a r t h  Curvature)  (metres)  Beam E l e v a t i o n A n g l e (degrees)  0.50  0.80  1. 19  1 .60  2. 10  2.60  3. 19  3.88  4.69  5.60  6.69  7 .88  9.30  1 1 . 10  13. 19  2000.  18.  28.  42.  56.  74.  91 .  111 .  135.  163.  195.  232.  273.  321.  381 .  449  4000.  36.  57.  84.  113.  147.  182.  223.  271 .  327.  390.  465.  546.  642.  761 .  897  6000.  54.  86.  127.  169.  222.  274.  335.  407.  491 .  586.  698.  819.  963.  1 142.  1347  8000.  73.  115.  169.  227.  296.  366.  448.  544.  656.  782.  931 .  1093.  1285.  1524.  1796  1OO00.  93.  145.  213.  284.  372.  459.  561 .  681 .  821 .  978.  1165.  1367.  1607.  1906.  2246  12000.  112.  175.  257.  343.  447.  552.  675.  818.  987 .  1175.  1399.  1642.  1930.  2289.  2697  14000.  135.  208.  303.  403.  525.  647.  791 .  958.  1 154.  1374.  1636.  1919.  2255.  2673.  3150  16000.  155.  239.  348.  462.  602.  741.  905.  1096.  1321 .  1572.  1871.  2195.  2578.  3057.  3601  18000.  176.  270.  393.  522.  678.  835.  1020.  1235.  1487.  1770.  2106.  2471 .  2902.  3440.  4053  20000.  198.  302.  438.  581 .  756.  930.  1135.  1374.  1654.  1968.  2342.  2747.  3226.  3824.  4505  22000.  221.  337.  486.  644.  835.  1027 .  1252.  1516. '  1824 .  2169.  2580.  3026.  3553.  4209.  4957  24000.  244.  369.  533.  704 .  913.  1122.  1368.  1656.  1992.  2369.  2817.  3303.  3878.  4596.  5412  26000.  266.  402.  579.  765.  992.  1218.  1485.  1796.  2160.  2568.  3054.  3581.  4203.  4981 .  5865  28000.  291 .  438.  629.  829.  1073.  1316.  1604.  1939.  2329.  2768.  3292.  3859.  4529.  5367.  6319  30000.  315.  472.  676.  891.  1152.  1413.  1721 .  2080.  2500.  2971 .  3532.  4139.  4857.  5755.  6775  32000.  339.  506.  724.  953.  1232.  1510.  1838.  2222.  2670.  3172.  3770.  4418.  5184.  6141.  7229  34000.  365.  543.  775.  1018.  1314.  1610.  1958.  2366.  2842 .  3375.  4011 .  4699.  5513.  6530.  7686  36000.  390.  579.  824.  1081 .  1394.  1708.  2077.  2508.  3012.  3577.  4250.  4979.  5841 .  6917.  8141  38000.  417 .  616.  875.  1146.  1477.  1808.  2198.  2653.  3185 .  3781 .  4491 .  5261 .  6171 .  7305.  8597  40000.  443.  652.  924.  1210.  1559.  1907.  2317.  2796.  3357.  3984.  4731 .  5542.  6499.  7695.  9055  SCEPTRE R a d a r Beam M e a s u r e m e n t  Altitude  , Ra"9e  ( C o r r e c t e I f o r S t a n d a r d Beam R e f r a c t i o n a n d E a r t h B  e  a  m  (metres)  0.01  0.01  0.02  E  Curvature)  (metres)  evatlon Angle degrees)  0.03  0.04  0.05  0.06  0.07  0.08  0. 10  0. 12  0. 14  0. 16  0. 19  0.23  420O0.  471 .  691 .  977.  1277.  1643.  2008.  2439  2942.  3530.  4189.  4974.  5825.  6830.  8083.  9511  44000.  497.  728.  1027.  1342.  1725.  2108.  2559  3086.  3702.  4392.  5215.  6106.  7159.  8474.  9970  46000.  526.  767.  1080.  1409.  1810.  2210.  2682  3232.  3877.  4598.  5458.  6390.  7490.  8866.  10427  48000.  554.  805.  1131 .  1475.  1893.  2310.  2803  3377.  4050.  4803.  5700.  6672.  7820.  9255.  10887  50000.  583.  845.  1185.  1543.  1978.  2413.  2926  3525.  4225.  5009.  5944.  6956.  8153.  9648.  11347  52000.  614.  886.  1239.  1611 .  2064.  2517.  3050  3672.  4401.  5217.  6188.  7241 .  8483.  10O38.  11805  54000.  642.  925.  1292.  1678.  2149.  2618.  3172.  3819.  4575.  5422.  6431 .  7525.  8817 .  10431.  12266.  56000.  673.  966.  1347.  1747.  2235.  2723.  3297.  3967.  4752.  5630.  6676.  7810.  9150.  10824.  12727.  58000.  704.  1008.  1403.  1817.  2322.  2827.  3422.  4116.  4929.  5838.  6922.  8096.  9484.  11216.  13187.  60000.  736.  1050.  1459.  1887.  2410.  2932.  3548.  4266.  5106.  6045.  7166.  8381 .  9817.  11610.  13649.  62000.  766.  1091.  1513.  1956.  2496.  3036.  3671.  4414.  5282.  6254.  7413.  8668.  10152.  12005.  14111 .  64000.  799.  1134.  1570.  2027.  2585.  3142 .  3798.  4564.  5461 .  6464.  7660.  8956.  10487.  124O0.  14574.  66000.  832.  1178.  1627.  2098.  2673.  3248.  3925.  4714.  5639.  6674.  7907.  9243.  10822.  12795.  15035.  68000.  866.  1222.  1684.  2170.  2763.  3354.  4052.  4866.  5818.  6885.  8155.  9532.  11158.  • 13189.  15499.  70000.  900.  1266.  1742.  2243.  2852.  3462.  4179.  5017.  5998.  7095.  8403.  9820.  11493.  13585.  15963.  72000.  934.  1311 .  1801 .  2315.  2943.  3569.  4307.  5169.  6178.  7307.  8650.  10107.  11830.  13981.  16427.  74000.  969.  1356.  1859.  2388.  3033.  3677.  4436.  5321 .  6358.  7516.  8899.  10397.  12167.  14378.  16892.  76000.  1004.  1402.  1919.  2462.  3124.  3785.  4565.  5474.  6539.  7728.  9148 .  10687.  12505.  14776.  17357.  7SOOO.  1039.  1448 .  1978.  2536.  3215.  3894.  4694.  5627.  6718.  7941 .  9398.  10977.  12843.  15173.  17823.  80000.  1076.  1494 .  2038.  2610.  3307.  4003.  4824 .  5781 .  6902 .  8154 .  9648.  11268.  13181.  15572.  18289.  V  SCEPTRE R a d a r Beam M e a s u r e m e n t A l t i t u d e ( C o r r e c t e d Range (metres)  f o r Standard  Beam R e f r a c t i o n a n d E a r t h  Curvature)  (metres)  Beam E l e v a t i o n A n g l e (degrees)  0.01  0.01  0.02  82000.  1112.  1541.  2099.  84000.  1149.  1589.  86000.  1186.  88000.  0.03  0.04  0.05  0.06  0.07  0.08  0. 10  0. 12  0. 14  0. 16  0. 19  0.23  '2685.  3399.  4113.  4954.  5935.  7084.  8367.  9899.  11559.  13520.  15970.  18755  2160.  2760.  3492.  4223.  5084.  6089.  7266.  8583.  10150.  11850.  13859.  16369.  19222  1636.  2221 .  2836.  3585.  4333.  5215.  6244.  7449.  8797.  10404.  12142.  14199.  16768.  19689  1224.  1684.  2283.  2912.  3678.  4444.  5346.  6400.  7632.  9012.  10656.  12437.  14539.  17168.  20157  90000.  1262.  1733.  2345.  2988.  3772.  4556.  5478.  6555.  7816.  9227.  10908.  12730.  14880.  17568.  20625  92000.  1300.  1782.  2408.  3065.  3867.  4667.  5610.  6711 .  8000.  9442.  11161.  13023.  15223.  17969.  21093  94000.  1341.  1833.  2473.  3143.  3961 .  4779.  5743.  6868.  8185.  9658.  11414.  13316.  15564.  18370.  21562  96000.  1381 .  1883.  2536.  3222.  4059.  4894.  5878.  7027.  8372.  9874.  11667.  13610.  15906.  18773.  22031  98000.  1420.  1933.  2600.  3301.  4154.  5007.  6012.  7184.  8557.  10093.  11923.  13905.  16248.  19175.  22500  100000.  1461.  1984.  2664.  3379.  4250.  5120.  6145.  7342.  8743.  10310.  12178.  14202.  16591.  19577.  22972  1020O0.  1503.  2037.  2731 .  3460.  4348.  5236.  6280.  7500.  8929.  10528.  12433.  14497.  16936.  19980.  23443  104OOO.  1544.  2089.  2796.  3540.  4445.  5350.  6416.  7661 .  9118.  10748.  12688.  14792.  17279.  20385.  23913.  106000.  1586.  2141.  2862.  3619.  4543.  5465.  6552.  7820.  9305.  10966.  12945.  15090.  17623.  20788.  24385.  108000.  1630.  2195.  2930.  3702.  4642.  5582.  6689.  7979.  9492.  11185.  13202.  15387.  17969.  21192.  24858.  110000.  1672.  2248.'  2996.  3782.  4740.  5697.  6825.  8141 .  9682.  11406.  13460.  15684.  18314.  21598.  25330.  112000.  1715.  2301 .  3063.  3863.  4839.  5813.  6961.  8302.  9870.  11626.  13717.  15983.  18659.  22003.  25802.  114000.  1760.  2357.  3132.  3947.  4940.  5932.  7100.  8464.  10061.  11848.  13974.  16281.  19006.  22408.  26277.  116000.  1803.  2411 .  3200.  4029.  5039.  6048.  7237.  8625.  10250.  12068.  14234.  16581.  19352.  22816.  26750.  118OO0.  1849.  2467.  3270.  4113.  5141 .  6167.  7377.  8789.  10441.  12291.  14492.  16880.  19700.  23221.  27226.  120OO0.  1894.  2522.  3338.  4196.  5241 .  6285.  7515.  8951 .  10631.  12512.  14753.  17180.  20047.  23630.  27700.  SCEPTRE R a d a r Beam M e a s u r e m e n t  Altitude  Range (metres)  Corrected  f o r Standard  Beam R e f r a c t i o n a n d  Earth Curvature)  (metres)  Beam E l e v a t i o n A n g l e (degrees) 0.01  0.01  0.02  0.03  0.04  0.05  0.06  0.07  1220CO.  1941 .  2579.  3409.  4281 .  5344.  6405  7656  124000.  1988.  2637.  3480.  4367.  5447.  6525  12G000.  2034.  2693.  3550.  4451 .  5548.  128000.  2082.  2752.  3622.  4537.  130000.  2130.  2810.  3695.  132000.  2177.  2868.  134O00.  2226.  136000.  0.08  0. 10  0. 12  0. 14  0.16  0.19  9115.  10824.  12736.  15011.  17480  20396.  24036.  28176  7794  9278.  11015.  12958.  15273.  17782  20743.  24445.  28651  6644  7936  9443.  11208.  13182.  15535.  18082  21093.  24853.  29128  5652.  6765  8077  9609.  11401.  13405.  15795.  18384  21444.  25263.  29603  4624.  5754.  6885  8218  9773.  11593.  13631.  16057.  18687  21792.  25673.  30081  3766.  4709.  5859.  7007  8360  9939.  11788.  13856.  16318.  18989  22143.  26081.  30557  2928.  3839.  4797.  5964.  7130  8503  10106.  11983.  14081.  16582.  19293  22493.  26493.  31036  2276.  2988 .  3913.  4885.  6069.  7253  8647  10271.  12176.  14307.  16846.  19597  22845.  26902.  31515  138000.  2324.  3046.  3985.  4972.  6173.  7374  8788  10439.  12372.  14534.  17110.  19900  23197.  27314.  31993  140000.  2375.  3108.  4060.  5060.  6280.  7498  8933  10607.  12568.  14761.  17373.  20205.  23550.  27726.  32473  142000.  2426.  3169.  4135.  5150.  6386.  7622  9077  10776.  12764.  14987.  17638:  20510.  23901.  28139.  32953  144000.  2477.  3231 .  4210.  5240.  6494.  7746  9222  10945.  12959.  15216.  17903.  20816.  24255.  28550.  33432  146OO0.  2529.  3293.  4286.  5330.  6601 .  7871  9368,  11114.  13157.  15444.  18169.  21122.  24609.  28963.  33913  148000.  2581 .  3356.  4363.  5420.  6709.  7997  9514 ,  11282.  13354.  15673.  18436.  21427.  24963.  29377.  34394  150000.  2634.  3419.  4439.  5511 .  6818.  8121  9658.  11452.  13553.  15903.  18702.  21734.  25318.  29792.  34876  152000.  2687.  3483.  4517.  5603.  6925.  8247  9805.  11623.  13751.  16133.  18969.  22042.  25673.  30206.  35358.  154000.  2741.  3547.  4594.  5695.  7034.  8373  9952.  11794.  13950.  16363.  19237.  22349.  26029.  30621.  35841.  156000.  2795.  3611 .  4672.  5787.  7144.  8501  10099.  11966.  14150.  16594.  19505.  22658.  26385.  31037.  36322.  158OO0.  2849.  3676.  4751 .  5880.  7254 .  8628  10247.  12137.  14349.  16825.  19773.  22967.  26739.  31453.  36806.  160000.  2904.  3741 .  4830.  5973.  7366.  8756  10396.  12310.  14550.  17056.  20042.  23276.  27096.  31869.  37290.  0.23  APPENDIX B Summary of AES D a i l y Raingauge L o c a t i o n s and Gauge/Rada Measurements  S t a t i o n Name A g a s s i z CDA A l o u e t t e Lake Bamberton Ocean Cement Buntzen Lake Burnaby C a p i t o l H i l l Burnaby Cariboo Dam Burnaby East Burnaby Mtn Terminal Burnaby Simon F r a s e r U C e n t r a l Saanlch I s l View C e n t r a l Saanlch Veyaness Chll1Iwack Ch1l11wack Gibson Road C o q u l t l a m Como Lake Ave C o q u l t l a m Lake Cordova Bay South Cowlchan Bay Cowlchan Lake Weir C u l t u s Lake D e l t a Ladner South D e l t a Tsawwassen Beach Duncan F o r e s t r y Edenbank SardIs Esqulmalt Metoc Gal1ano South 2 Gambler Harbour Ganges Mansel1 Rd Gibsons Gower P o i n t Haney C o r r l I n s t n Haney East Haney UBC RF Admin H o l l y b u r n Ridge Hopkins Landing loco Refinery Langley P r a i r i e Mayne I s l a n d Metchosln M e t c h o s l n Happy V a l l e y M111 Bay K l l m a l u Mlsslon M i s s i o n H a r t l e y Rd M i s s i o n West Abbey Nanlamo Departure Bay N Vancouver C a p l l a n o N Vancouver C l e v e l a n d N Vancouver C l o v e r l y N Vane Grouse Mtn Resort N Vancouver Lynn Creek N Vancouver Redonda Dr *  Location UTM Coordinate L a t i t u d e Longitude North East 49" 49' 48' 49* 49' 49' 49' 49' 49' 48' 48' 49" 49' 49* 49' 48* 48' 48' 49' 49* 49* 48' 49' 48' 48' 49' 48* 49* 49' 49* 49* 49' 49' 49* 49' 48' 48' 48' 48' 49' 49' 49* 49' 49' 49' 49' 49' 49* 49'  15' 17' 35' 23' 17' 15' 13' 16' 17' 34' 35' 07' 11' 16' 22' 31' 44' 50' 05' 04' 01' 47' 08' 26' 53' 27' 52' 23' 15' 12' 16' 22' 28' 18' 09' 50' 23' 25' 39' 08' 15' 09' 13' 20' 22' 19' 23' 22' 22'  121* 122' 123" 122' 122' 122' 122' 122* 122' 123' 123' 122' 121' 122' 122' 123' 123' 124' 121' 123' 123' 123' 121' 123* 123" 123' 123* 123' 122' 122' 122" 123' 123' 122' 122' 123' 123' 123' 123' 122' 122' 122' 123' 123' 123' 123' 123' 123" 123'  46' 29' 31' 52' 59' 55' 45' 56' 55' 22' 25' 06' 53' 52' 48' 22' 35' 04' 59' 05' 06' 41' 58' 26' 21 ' 26' 30' 32' 31 ' 34' 34' 12' 29' 53' 39' 16' 32' 33' 33' 18' 14' 16' 57' 06' 06' 03' 05' 02' 05'  5455000 5459100 5381400 5469000 5459000 5455000 5450500 5457000 5458500 5379700 538140O 5441700 5448300 5456600 5466500 5373600 5396700 5408200 5436300 5434600 5429900 5403400 5442600 5364000 5414400 5476700 5412500 5470100 5454400 5450OO0 5456600 5469400 5474500 5461COO 5443700 5408700 5358700 5362500 5388400 5443000 5455300 5444600 5451100 54640O0 5467300 5462900 5469400 5467300 5467500  590000 537500 461600 510000 501000 506000 503500 505000 506000 473000 469200 566400 5813CO 5097CO 516300 473000 457000 422300 574500 494000 492700 449700 57580O 468000 474400 468500 463300 461100 535100 531500 531200 486200 465300 508500 525900 480400 460400 460600 459200 551000 555800 5533CO 430500 492700 492300 496700 494000 498100 493500  Dec 20  Gauge/Radar Measurements Dec 21 Feb 12 Feb 13 F«b 14  12 /16 54 /21  14 /14 32 /13  12 /10 27 /11  25 /IB 20 /20  11 /17 33 /32  58 /28 33 /25 34 /20  62 /18 38 /15 27 /12  39 /16 23 /13 23 /11  34 /21 24 /16 15 /14  40 /25 10 / I I 12 /13  33 41 16 15 19 19 30  37 34 13 11 25 22 34  23 24 16 8 23 17 25 37  22 15 16 10 24 25 15 36  11 12 11 14 33 10 9 45  /  /  /20 /27 /11 /12 /13 /16 /22  / /  25 /10 14 31 28 34 17 13 23 43 30 28 47 37  /  /io /22 /20 /16 /1T /io /12 /15 /15 /12 /31 /24  /  60 36 43 40 22 12 14 21 28  /18 /17 /28 /34 /14 / 8 /10 /10 /18  28 15 37 42 30 59 50 40  /28 /10 /21 /20 /19 /22 /22 /21  /  /  /  /11 /18 /10 /10 /II /15 /15  / /  /  /  /II /16 /11 /12 /11 /12 /13 /17  /  16 / 7  13 / 7  15 19 16 20 17 11 16 40 2 29 30 23  22 21 20 16 18 10 18 26 13 18  /  / 8 /15 /13 / 7 /13 / 8 / 9 /13 /11 /10 /17 /14  /  59 /11 47 /13 34 /19 20 /16 15 / 9 1 1/ 9 13 / 9 19 / 7 23 /IS 23 20 40 50 40 72 55 46  /  /18 / 5 /17 /15 /13 /16 /16 /17  /  /  /  /14 /16 /16 /14 /18 /18 /17 /25  /  7 / 8  /  /  25*/15 10 /12 10 /12 16 / 8 24 /20 16 /16 13 /11 13 / 7 10/8 9 / 5  12 12 4 11 9 9 4 7 6 4  24 /12 40 /14 35*/15  15 /16 29 /15 17 / 6  42 14 13 12 16 26 22 25 14 25  10 14 14 16 14 24 25 21 9 17  26 33 13 18 12 7 7 27 18 14 37 14 3 19  /  /15 /11 / 8 / 9 / 9 /12 /13 /13 / 8 /17  /  25 /13 51*/17  /  27 /15  Mixed r a i n and snow: snowfall converted to water e q u i v a l e n t and added t o r a i n f a l l  / /  /  /20 /14 /15 /15 /11 /18 /23 /21 / 5 /16  /  23 /18 13 /20  / /  value  /14 /13 / 1 / 3 /23 /20 /16 /25  /  15 / 8  /13 /16 /16 / 9 /12 / 6 /II /II /11 /11  / /  /  /  /16 / 3 / 1 / 5 /17 / 7 / 0 / 6 / 0 / 0  / /  /27 /14 / 2 /16 /15 / 0 / 8 / 9 /10 /20 /30 /22 / 2 /11  /  18 /18 10 /20  / /  S t a t i o n Name  Location UTM Coordinate L a t i t u d e Longitude North East  N Vancouver Seymour B l v d N Vane Sonara Dr N Vancouver Upper Lynn N Vancouver Wharves Piers Island P i t t Meadows STP P i t t Polder Point Atkinson Port Mellon P o r t Moody Gulf 011 Rfy Richmond Geal Rd Richmond Nature Park Roseda1e S a a n l c h t o n CDA S a l t s p r i n g Is Cusheon Lk S a l t s p r l n g St Mary's L Saturna I s l a n d L i g h t Seymour F a l l s Shawn1gan Lake Sooke Sooke Lake North South Pender I s l a n d Sumas Canal S u r r e y Kwantlen Park Surrey Municipal H a l l S u r r e y Newton Surrey Sunnyslde Vancouver C i t y H a l l Vancouver Dunbar South Vancouver UBC Vancouver West 10th V i c t o r i a Gordon Head V i c t o r i a Highland V i c t o r i a Marine V i c t o r i a P h y l l i s Street V i c t o r i a Portage I n l e t V i c t o r i a P r i n c e s s Ave V i c t o r i a Prospect Lake Victoria U Vic W Vane B a l l a n t r e e P l a c e W Vane C a p l l a n o GCC W Vancouver Dundarave West Vancouver Mathers Whalley Forest Nursery White Rock STP WI111am Head  49* 49' 49* 49' 48' 49' 49' 49' 49* 49* 49' 49' 49* 48* 48* 48* 48' 49' 48* 48" 48' 48' 49' 49* 49" 49' 49" 49' 49' 49* 49' 48' 48' 48' 48* 48' 48' 48' 48' 49' 49' 49' 49' 49' 49' 48'  *  19' 22' 21 ' 19' 42' 13' 18' 20' 31' 17' 09' 10' 11' 37' 49' 53' 47' 26' 39' 22' 34' 45' 07' 12' 06' 08' 03' 17' 15' 15' 16' 28' 30' 22' 27' 27' 26' 31 ' 28' 22' 21 ' 20' 20' 11' 01' 21 '  123* 123" 123" 123' 123' 122' 122' 123" 123' 122" 123* 123* 121* 123" 123" 123" 123' 122' 123" 123' 123" 123' 122' 122' 122* 122* 122' 123' 123' 123' 123" 123' 123' 123' 123' 123' 123" 123* 123' 123" 123" 123" 123' 122" 122' 123"  01' 06' 02' 07' 25' 42' 38' 16' 29' 53' 10' 06' 48' 25' 27' 33' 03' 58' 37' 44' 39' 13' 07' 52' 50' 51 ' 48' 07' 11' 15' 10' 18' 30' 45' 16' 26' 21 ' 26' 20' 08' 07' 1 1' 11 ' 50' 46' 32'  5462500 5467000 5465700 5462400 5395000 5450400 5460700 5464O0O 5485300 5458500 5444000 5446300 5448O0O 5385300 5406500 5414400 5403200 5476200 5389O00 5357OO0 5380500 5399000 544050O 5448700 5439000 5443O00 5433000 5456300 5449900 5456700 5456500 5369O0O 5371700 5357500 5366500 5367000 5364000 5366000 5367600 5467400 5466700 5464600 5465100 5447200 5429000 5354000  498700 491000 498000 491500 469400 522000 526700 480800 464700 508300 488000 493200 587lOO 469500 466400 460200 496700 502500 454300 446000 452100 484000 5650O0 510300 512600 5110O0 5150O0 491800 486800 481500 488700 477500 463000 444500 480000 468000 474300 471500 477000 4907OO 491100 486600 486400 512600 517000 4605OO  Dec  20  Gauge/Radar Measurements Dec 21 Feb 12 Feb 13 Feb 14  43 /22 41 /20  32 /14 32 /15  30 19 37 43 18 44 42 27 31 12 18 24 28 5 56 25 16 28 18 22 31 34 31 30  40 13 26 31 23 45 41 19 21 16 14 16 21 2 72 19 12 16 11 16 21 47 24 19  /  /19 /12 /24 /28 /14 /16 /19 /16 /19 /12 /12 /13 /18 /14 /28 /13 / 7 /12 /10 /13 /20 /22 /18 /29  /  /  /14 / 9 /13 /15 /11 /14 /II /11 /12 /11 / 9 / 8 /11 / 9 /20 / 7 / 8 / 7 / 9 /11 /10 /12 / 8 /14  /  28 /16 29 /15  26 /10 24 / I I  13 22 12 12  10 9 16 7  /  / 9 /10 / 7 / 9  /  /  / 8 / 8 / 8  / t 1 8 9 /  15 / 9 16 / 9  12 / 8  49 /20 44 /20 41 /17  49 /15 47 /15 26 /13  29 /20 10 / 7  17 / I I 10 / 9  /  / /  /  / /  25 /14  21 /19  19 /15 12 / 9 28 /13 24 /13 20 /14 33 /12 26 /12 24 /15 22 /14 14 / H 15 / H 16 / 9 16 /11 9 /13 47*/21 21 /11 14 / 8 25 /15 10 / 9 24 /11  22 /14 13 /13 13 /16 16 /21 10 /12 48 /14 16 /16 12 /12 15 /13 22 /21 14 /13 12 / 8 10/9 9 /12 73 /34 18 /12 13 / 9 26 /17 14 /13 23 /18  10 / 9 16 / 2 18 /16 31 /27 4 / 6 19 / 8 15 /16 3 / 3 12 / 6 12 /18 14 / 4 8 / 1 10/0 5 / 0 47 /26 26 /14 17 / 8 36 /19 6 / 1 11 /23  30 /12 13 /14 29 /15  12 /15 15 /13 16 /16  6 / 8 20 /11 6 / 7  /13 /14 /17 / 7 / 8 /10 / 6 / 6 / 5 / 5 / 4 /16 /16  14 /12 11 /12  6 / 5 5 / 3  / /  /  21 21 23 7 18 17 7 11 7 14 7 18 19  /  / /  21 /14 22 /14 9 / 9  Mixed r a i n and snow: snowfall converted to water e q u i v a l e n t and added to r a i n f a l l  v  / /  /  /  13 17 7 15 16 15 14 15 26  /  /16 /13 / 9 /15 /15 /15 /15 /14 /16  / / / /  10 /13 13 /13 value  23 /19  / /  /  /  8 20 14 5 8 8 14  /  / / / / / / /  /  3 9 9 3 7 3 4  26 /14  / / / /  4 / 6 4 / 6  APPENDIX C F l o w c h a r t Showing CAPPI Image G r i d E x t r a c t i o n , E r r o r C o r r e c t i o n , Data T r a n s f e r , and Image G e n e r a t i o n P r o c e s s e s  122  calculate radar Measurement altltudaa  RORELEV.FTN  chack d a t a a r r o r s , a a l a c t Image a r a a , c o n v a r t DVIP v a l u a s t o r a i n f a l l , produca aaq. a cum. l u g e f i l e s a hyetogxapha GlNIMAGE  character c o n v e r t 1on and f i l e r a f o r• a t  produce leohyeta! or 3-d a u r f a c a representst1ona  123  tannine! emulation a file tranefer TERM.BAS  F I 11n* •dltop  E0LIN.COM  cleaned-up luge file  iMga dlaplay » Interactive ana 1 ya 1 a  RORIMAGE.BAS  rapid ••quant 1a1 Image d l s p l a y  MOVIE.BAS  

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