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Temperature microstructure in Howe Sound Bilodeau, Laurent Ernest 1979

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TEMPERATURE MICROSTRUCTURE IN HOWE SOUND by LAURENT ERNEST BILODEAU B. A. Sc. L a v a l U n i v e r s i t y , 1972  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE  REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in  THE  FACULTY OF GRADUATE STUDIES i n the Department o f P h y s i c s and the  I n s t i t u t e o f Oceanography  We accept t h i s t h e s i s as conforming to the required  THE  standard  UNIVERSITY OF BRITISH COLUMBIA SEPTEMBER 1978  Laurent Ernest Bilodeau, 1978  In  presenting  an  advanced  the I  Library  further  for  this  degree shall  agree  scholarly  by  his  of  this  written  at make  that  for  freely  It  British  12  QMtA  of  Columbia,  British  by  for  gain  Columbia  shall  that  not  the  requirements  reference copying  t h e Head  is understood  of of  of  for extensive  permission.  University  fulfilment  available  may b e g r a n t e d  financial  2075 Wesbrook P l a c e Vancouver, Canada V6T 1WS  Date  it  permission  purposes  thesis  in p a r t i a l  the U n i v e r s i t y  representatives.  Department The  thesis  of  I agree and this  be a l l o w e d  or  that  study. thesis  o f my D e p a r t m e n t  copying  for  or  publication  without  my  Abstract  Temperature m i c r o s t r u c t u r e o b s e r v a t i o n s Sound a r e p r e s e n t e d  i n Howe  and r e l a t e d t o t h e i r o c e a n o g r a p h i c c o n t e x t ,  some i n s t a n c e s , two f r e e - f a l l i n g taneously  obtained  with separations  to l o o k a t t h e l a t e r a l  probes have been l a u n c h e d  o f 10 t o 20 m a t t h e s u r f a c e  extent  In  simul-  i n an attempt  of temperature m i c r o s t r u c t u r e  features.  P a t c h e s o f temperature g r a d i e n t v a r i a n c e were found where t h e gradient presented  peak v a l u e s  of both signs a t smaller scales.  These  p a t c h e s w e r e u s u a l l y o b s e r v e d b y o n e p r o b e o n l y a n d seem t o e x t e n d e r a l l y o v e r l e s s t h a n 20 m. took mostly detected icantly  by both probes, i n d i c a t i n g l a r g e r t h a n 20 m.  their  instances  t h e same s i g n w i t h i n a g i v e n p a t c h .  also discussed for  I n other  t h e peak g r a d i e n t  an e x p l a n a t i o n  existence.  Basin,  t h e Deep W a t e r o c c a s i o n a l l y  r e c e i v e s l a r g e i n f l u x e s o f water from t h e S t r a i t o f Georgia. stays e s s e n t i a l l y  trapped  homogeneous w i t h t i m e .  behind  a 75 m d e e p s i l l  A model i s p r e s e n t e d  the molecular  which r e l a t e s the rate a t  c o e f f i c i e n t of heat d i f f u s i o n .  water column a r e d i s c u s s e d of v e r t i c a l heat  transport.  Otherwise,  a n d b e c o m e s more  w h i c h t e m p e r a t u r e becomes h o m o g e n e o u s t o t e m p e r a t u r e g r a d i e n t and  i s signif-  of temperature m i c r o s t r u c t u r e a r e  i n terms o f mechanisms t h a t c o u l d p r o v i d e  I n Howe S o u n d ' s I n n e r  it  values  Such p a t c h e s were u s u a l l y  that t h e i r h o r i z o n t a l extent  These types  lat-  variance  Other p a r t s of the  i n terms o f t h e Osborn-Cox (1972) model  i i i  Table of contents Page  Abstract Table of contents  i  i  i  i  i  List  of tables  List  of figures  v i i  Acknowledgments  x i  Chapter I :  v i  Introduction  1  1.1  General  1  1.2  Howe Sound: g e o g r a p h y , t i d e s ,  introduction  and r i v e r 1.3  Earlier  winds  discharge  2  investigation of the  p h y s i c a l o c e a n o g r a p h y o f Howe S o u n d  Chapter I I :  4  New a s p e c t s o f t h e o c e a n o g r a p h i c and c u r r e n t m e t e r d a t a  10  II. 1  The I n t e r m e d i a t e Water  II.2  T h e Deep W a t e r r e n e w a l i n t h e F a l l o f 1 9 7 3  C h a p t e r I I I : M i c r o s t r u c t u r e methods  .  10 .  .  13  and d a t a p r o c e s s i n g .  .  17  III.l  Probes and r e s o l u t i o n  17  III. 2  Method o f d a t a p r o c e s s i n g  19  III. 3  Summary o f t h e d a t a  21  iv  Page  Chapter IV:  Temperature s t r u c t u r e of Howe Sound i n November 1 9 7 3 and February 1974  .  .  .  .  24  IV.1  Temperature s t r u c t u r e i n November 1 9 7 3  .  .  .  24  IV.2  Temperature s t r u c t u r e i n February 1974  .  .  .  27  a)  Recent  e v o l u t i o n o f water p r o p e r t i e s i n  Howe Sound  27  b)  Temperature s t r u c t u r e i n t h e Outer B a s i n  .  c)  Temperature s t r u c t u r e i n the Inner B a s i n ' s  .  I n t e r m e d i a t e Water d)  30  Temperature s t r u c t u r e i n the Inner B a s i n ' s Deep Water  IV. 3  28  32  Discussion a)  An I n t e r m e d i a t e Water c i r c u l a t i o n p a t t e r n ? .  b)  The Osborn-Cox model  c)  A model f o r an i s o l a t e d  .  35 and inhomogeneous  volume o f f l u i d  Chapter V:  34  D e t a i l e d a s p e c t o f temperature  41  microstructure  .  44  V. l  Introduction  44  V.2  Detailed profiles  45  a)  November 1 9 7 3 p r o f i l e s  45  b)  Outer B a s i n , February 1974  c)  Inner B a s i n I n t e r m e d i a t e Water (February 1 9 7 4 )  50  d)  Inner B a s i n Deep Water (February 1 9 7 4 )  57  .  .  .  .  47  Page  V.3  Discussion a)  Summary o f m i c r o s t r u c t u r e d e s c r i p t i o n  b)  R e l a t i o n s h i p between temperature  59  and  temperature gradient m i c r o s t r u c t u r e of microstructure  . . .  . . . .  60  c)  L a t e r a l extent  62  d)  Turbulent or not?  64  e)  D o u b l y - d i f f u s i v e or not?  67  Chapter V I : Conclusion  70  References  72  Tables  75  Figures  78  List  List  of Tables  of the locations  and times a t which  double  d r o p s w e r e made d u r i n g t h e F e b r u a r y 1974 m i c r o structure of  cruise,  together with  t h e probes a t l a u n c h and r e c o v e r y .  List  of the locations  and times a t which  d r o p s w e r e made d u r i n g structure for  the separation  cruise,  single  t h e November 1 9 7 3 m i c r o -  together with  t h e mean s q u a r e v e r t i c a l  the values observed  temperature  Mean s q u a r e v a l u e s o f t h e v e r t i c a l  gradient.  temperature  g r a d i e n t and n e t t e m p e r a t u r e change o b s e r v e d a c r o s s t h e I n t e r m e d i a t e Water d u r i n g t h e F e b r u a r y 1974 m i c r o s t r u c t u r e  cruise.  vii  List  of Figures  Fig.  1  Chart  o f Howe S o u n d .  Fig.  2  L o n g i t u d i n a l s e c t i o n o f Howe Sound a n d c r o s s s e c t i o n s made a t t h e s i l l  Fig.  3  a n d a t s t a t i o n Howe 4.  T y p i c a l w i n t e r p r o f i l e s o f t e m p e r a t u r e and s a l i n i t y Outer B a s i n and i n t h e Inner  Fig.  4  channel  i n the  B a s i n o f Howe S o u n d .  Time s e r i e s o f t e m p e r a t u r e o b s e r v a t i o n s  obtained  i n the  O u t e r B a s i n a t d e p t h s o f 100 m a n d more. Fig.  5  Time s e r i e s o f t e m p e r a t u r e a n d s a l i n i t y  observations  o b t a i n e d b e t w e e n 20 a n d 75 m i n b o t h b a s i n s o f Howe S o u n d . Fig.  6  Time s e r i e s o f o b s e r v a t i o n s  o f (a) temperature,  (b) s a l i n i t y ,  ( c ) s i g m a - t a n d ( d ) d i s s o l v e d o x y g e n a t d e p t h s o f 100 m and Fig.  7  more a t s t a t i o n Howe 4 ( I n n e r B a s i n ) .  L o n g i t u d i n a l s e c t i o n o f Howe Sound s h o w i n g t h e l o c a t i o n o f the I n t e r m e d i a t e  Fig.  8  W a t e r a n d o f t h e Deep W a t e r .  D i s t r i b u t i o n of temperature, oxygen along  salinity  the center of t h e Inner  and d i s s o l v e d B a s i n on  September 20, 1973. Fig.  9  D i s t r i b u t i o n o f T, S a n d D.0. a l o n g Inner  F i g . 10  11  13, 1973.  D i s t r i b u t i o n o f T, S a n d D.0. a l o n g Inner  Fig.  B a s i n o n November  B a s i n on January  the center of the  the center ofthe  22, 1974.  T i m e s e r i e s o f t e m p e r a t u r e a n d N-S c u r r e n t obtained  velocity  a t s t a t i o n Howe 4 a t a d e p t h o f 150 m b y a n  A a n d e r a a c u r r e n t m e t e r b e t w e e n O c t o b e r 3 a n d November  15, 1973.  viii  Fig.  12  Description of  Fig.  13  o f a "Pumpkin" m i c r o s t r u c t u r e  i t stemperature sensing  Location  p r o f i l e r and  element.  of the microstructure  p r o f i l e s obtained i n  Howe Sound i n November 1 9 7 3 . Fig.  14  Overall profile  o f Drop P-10.  Fig.  15  Overall profile  o f Drop P - l l .  Fig.  16  Overall profile  o f Drop P-12.  Fig.  17  Overall profile  o f Drop P-13.  Fig.  18  Overall profile  o f D r o p P-14.  Fig.  19  Overall profile  o f Drop P-15.  Fig.  20  Overall profile  o f D r o p P-16.  Fig.  21  Detailed  segment f r o m Drop P-12.  Fig.  22  Detailed  segment f r o m Drop P-12.  Fig.  23  Detailed  segment f r o m D r o p P - 1 3 .  Fig.  24  Detailed  segment f r o m Drop P-13.  Fig.  25  STD l o n g  c h a n n e l s e c t i o n made o n November 2 2 , 1 9 7 4  in Fig.  26  the Inner Basin  STD c r o s s  o f Howe S o u n d .  c h a n n e l s e c t i o n made o n November 2 2 , 1 9 7 4  a t s t a t i o n Howe 4. Fig.  27  STD c r o s s  c h a n n e l s e c t i o n made o n November 2 2 , 1 9 7 4  a t s t a t i o n Howe 4.7. Fig.  28  Location  of themicrostructure  Howe Sound i n F e b r u a r y 1 9 7 4 . Fig.  29  Overall profile  o f D r o p 6.  Fig.  30  Overall profile  o f D r o p 7.  Fig.  31  Overall profile  o f D r o p 8.  p r o f i l e s obtained i n  ix  Fig.  32  O v e r a l l p r o f i l e o f Drop 9.  Fig.  33  O v e r a l l p r o f i l e o f Drop 1 0 .  Fig.  34  Deep p a r t of Drop 7 w i t h an expanded temperature  scale.  Fig.  35  Deep p a r t o f Drop 8 w i t h an expanded temperature  scale.  Fig.  36  Deep p a r t o f Drop 9 w i t h an expanded temperature s c a l e .  Fig.  37  Deep p a r t of Drop 10 w i t h an expanded temperature  Fig.  38  Comparison between STD p r o f i l e s  scale.  made on January 22 and  February 4, 1 9 7 4 , i n both Howe Sound's b a s i n s . Fig.  39  STD l o n g channel s e c t i o n made on February 6, 1 9 7 4 i n Howe Sound's Inner B a s i n .  Fig.  40  STD c r o s s channel s e c t i o n made a t s t a t i o n Howe 4 on February 6, 1 9 7 4 .  Fig.  41  Detailed  p r o f i l e from Drop 6.  Fig.  42  Detailed  p r o f i l e from Drop 6.  Fig.  43  Detailed  p r o f i l e from Drop 6.  Fig.  44  Detailed  p r o f i l e from Drop 7.  Fig.  45  Detailed  p r o f i l e from Drop 7.  Fig.  46  Detailed  p r o f i l e from Drop 7.  Fig.  47  Detailed  p r o f i l e from Drop 8.  Fig.  48  Detailed  p r o f i l e from Drop 8.  Fig.  49  Detailed  p r o f i l e from Drop 9.  Fig.  50  Detailed  p r o f i l e from Drop 9.  Fig.  51  Detailed  p r o f i l e from Drop 9.  Fig.  52  Detailed  p r o f i l e from Drop 10.  Fig.  53  Detailed  p r o f i l e from Drop 10.  X  Fig.  54  Detailed  p r o f i l e f r o m Drop 1 0 .  Fig.  55  Detailed  p r o f i l e f r o m t h e Deep W a t e r o f D r o p  7.  Fig.  56  Detailed  p r o f i l e f r o m t h e Deep W a t e r o f D r o p  7.  Fig.  57  Detailed  p r o f i l e f r o m t h e Deep W a t e r o f D r o p  8.  Acknowledgments  I am s u p p o r t and to the  like  Dr  G.  L.  this thesis.  occasional  t o t h a n k Dr  c r i t i c i s m of  i n d e b t e d t o Dr  Thomas O s b o r n f o r  advice through a l l phases of the  completion of  p a t i e n c e and also  greatly  the  Pickard  and  comments a b o u t t h e  experience,  lead  f i n a n c i a l help,  i t were a l l i n v a l u a b l e .  I would  P a u l L e b l o n d f o r h i s d e t a i l e d and  positive  early  lack of  His  work w h i c h  his  and  Dr  early  R.  final W.  d r a f t s of  Burling  draft.  this thesis,  for very  and  appropriate  1  Chapter  I  Introduction  1.1  General  Introduction.  The p u r p o s e s t r u c t u r e and f i n e  of t h i s t h e s i s i s to present temperature  micro-  s t r u c t u r e o b s e r v a t i o n s w h i c h w e r e o b t a i n e d i n Howe  Sound i n November 1973 a n d F e b r u a r y 1 9 7 4 , a n d t o i n v e s t i g a t e some o f their  significance.  The t e r m " m i c r o s t r u c t u r e " a p p l i e s t o t h e d i s t r i b u t i o n o f oceanographic  p r o p e r t i e s a t s c a l e s s m a l l e r t h a n one m e t r e .  Observa-  t i o n s r e p o r t e d b y Gregg e t a l . (1973) i n an o c e a n i c environment t h a t most o f t h e v a r i a n c e o f t h e temperature s c a l e s s m a l l e r t h a n 0.1 m. of  the temperature  s c a l e s o f i m.  g r a d i e n t i s found a t  I n the d i s t r i b u t i o n of s p e c t r a l  densities  g r a d i e n t , G r e g g e t a l . f o u n d a s p e c t r a l minimum  G a r g e t t (1976) u s e d  as a p p l y i n g t o s c a l e s l a r g e r  this  to define "fine  than a metre,  Gargett's d e f i n i t i o n i s retained f o r this "microstructure" w i l l  Little  show  apply here  i s known a b o u t  near  structure"  up t o t e n s o f m e t r e s . t h e s i s and, consequently,  t o s c a l e s s m a l l e r t h a n one m e t r e .  t h e o c c u r r e n c e and t h e r o l e o f temper-  a t u r e m i c r o s t r u c t u r e i n f j o r d s and i n l e t s .  Drinkwater  (1973)  used  temperature m i c r o s t r u c t u r e o b s e r v a t i o n s i n a study of the r o l e of t i d a l mixing i n Rupert  and H o l b e r g I n l e t s  to detect the occurrence of  2  turbulent  stirring.  He f o u n d t h a t t u r b u l e n t s t i r r i n g  association with t i d a l winds. less  occurred i n  currents and, near the surface, w i t h  He t r a c e d a m i d - d e p t h  intrusion  into Holberg Inlet  surface and observed  t e m p e r a t u r e m i c r o s t r u c t u r e away f r o m t h e m o u t h o f t h e i n l e t .  other published  study d e s c r i b e d o r used  temperature  No  microstructure  observations obtained i n i n l e t s .  Howe S o u n d was c h o s e n f o r t h i s a c c e s s and because  study because  i t i s easy o f  i t has been t h e f o c u s o f s e v e r a l i n v e s t i g a t i o n s  h a v e p r o v i d e d much b a c k g r o u n d  i n f o r m a t i o n about i t s oceanography  which  f o r the  p e r i o d o f 1971 t o 1974.  1.2  Howe Sound: g e o g r a p h y ,  t i d e s , wind, r i v e r discharge.  Howe Sound i s a f j o r d Vancouver, It  inlet  located  30 km N o r t h W e s t o f  on t h e m a i n l a n d c o a s t o f t h e S t r a i t  of Georgia (seefig.  1).  c o n s i s t s o f two b a s i n s s e p a r a t e d b y a s i l l w i t h a maximum d e p t h o f  70 m ( s e e f i g .  1 ) . The O u t e r B a s i n ( a l s o c a l l e d  a number o f i s l a n d s a n d p a s s a g e s . C h a r l o t t e Channel, i s about  South Basin)  The s o u t h e r n m o s t  passage,  features t h e Queen  250 m deep a l o n g i t s e n t i r e l e n g t h .  The  I n n e r B a s i n ( a l s o c a l l e d N o r t h B a s i n ) h a s a maximum d e p t h o f 290 m and a mean w i d t h o f a b o u t  3 km.  The s i l l  i s l o c a t e d 28 km f r o m t h e  m o u t h o f Howe S o u n d a n d 17 km f r o m t h e h e a d . of  the s i l l  i s presented i n fig.  2.  A cross channel  profile  3  Point Atkinson Sound.  i s the closest  At Point Atkinson,  tidal  the amplitude  r e f e r e n c e p o i n t t o Howe  r a t i o o f the four main  consti-  tuents i s : .l M + K  °1 S  +  2  _  2.810 2.979  2  + +  1.555 0.748  _  .  Defant  (1961, p.307) d e s c r i b e s s u c h a v a l u e o f t h e r a t i o as a m i x e d ,  mainly  semi-diurnal type.  Sound) i s s m a l l e r t h a n  The t i d a l  r a n g e a t S q u a m i s h ( h e a d o f Howe  that of Point Atkinson  a few c e n t i m e t r e s w h i l e t h e phases l a g b e h i n d by  a few minutes  Point Atkinson  The graphic  (Canadian  tidal  mean t i d a l  S e r v i c e , 1977).  the s i l l  those  of Point  S e r v i c e , 1977).  For the purpose of a simple i s a b o u t 45 m.  tidal  I f t h e f l o w were  Hydro-  prism  which suggests  smaller but not negligible  that baroclinic  Buckley  tides  model,  uniform  a n d i f t h e t i d e was p u r e l y s e m i - d i u r n a l , t h e mean  reports a calculation  tidal (1977)  have a  effect.  Atmospheric Environment S e r v i c e operates  which i s located i n the center of the v a l l e y , t h e s i t e o f FMC o f C a n a d a L t d . records  Thus t h e  r a n g e a t S q u a m i s h i s 3.1 m ( C a n a d i a n  r a n g e w o u l d g i v e r i s e t o p e a k v e l o c i t i e s o f 8.5cm/sec.  The  Atkinson  p r e d i c t i o n s c a n b e u s e d a c c u r a t e l y i n Howe S o u n d .  t h e mean d e p t h o f t h e s i l l over  Hydrographic  ( m o u t h o f Howe S o u n d ) b y  a n anemometer  c l o s e t o t h e w a t e r , on  ( f i g . 1 ) , near Squamish.  t h e h o u r l y wind r u n and d i r e c t i o n  steep mountains which l i n e the v a l l e y ,  i n octants.  The anemometer Because o f t h e  t h e wind blows o n l y seldom  the E a s t o f t h e West.  Down-inlet winds dominate d u r i n g w i n t e r  to March) and u p - i n l e t  winds dominate d u r i n g  from  (October  t h e summer ( A p r i l t o  August). that  A more d e t a i l e d  study of the hourly wind records reveals  t h e r e a r e p e r i o d s when t h e d i u r n a l w i n d c y c l e a c c o u n t s f o r m o s t  of t h e v a r i a n c e i n t h e wind p a t t e r n s . of l a r g e r weather  systems which predominates w i t h p e r i o d s o f l i g h t o r  strong winds l a s t i n g  The of the i n l e t .  At other times, i t i s the effect  f r o m one t o f o u r  Squamish  days.  R i v e r c o n s t i t u t e s t h e main  f r e s h water  tributary  H o u r l y d i s c h a r g e measurements a r e t a k e n a t t h e D a i s y  L a k e Dam a t B r a c k e n d a l e , 25 km n o r t h o f S q u a m i s h Canada s t a t i o n 8GA22).  The r i v e r  (Water Survey o f  discharge i s typically  3  100 m / s e c  3  in winter (May  (November t o A p r i l ) a n d t y p i c a l l y .3.00 m / s e c i n summer  t o September).  The d a i l y d i s c h a r g e c a n be e x p e c t e d t o p e a k  o c c a s i o n a l l y a t several times these values.  discharg 3 o f t h e y e a r 1 9 7 3 o c c u r r e d o n O c t o b e r 28 w i t h a mean r a t e o f 1 1 7 0 m / s e c  I.3  Earlier  The h i g h e s t d a i l y  i n v e s t i g a t i o n s o f Howe S o u n d ' s P h y s i c a l  Many i n v e s t i g a t o r s h a v e v i s i t e d Howe S o u n d . gives a detailed  list  going back  t o C a p t a i n Vancouver.  Oceanography.  Buckley  (1977)  In this  study,  r e f e r e n c e i s made o n l y t o r e c e n t i n v e s t i g a t i o n s w h i c h c o v e r e d b o t h b a s i n s and t h e e n t i r e water column,  I n 1968,  t h e M a r i n e S c i e n c e s Branch o f t h e Department  E n v i r o n m e n t o f Canada c a r r i e d of Georgia which r e s u l t e d Ages,  1971).  c o n t i n u o u s l y o r on a monthly  a program  basis.  ofthe  of observation of the Strait  i n m o n t h l y c r u i s e s i n Howe S o u n d  The I n s t i t u t e o f O c e a n o g r a p h y  (Crean and  has c a r r i e d out a  program  5  of  monthly  c r u i s e s i n Howe S o u n d b e t w e e n S e p t e m b e r 1 9 7 1 a n d M a r c h 1 9 7 4  and  the data are a v a i l a b l e  The  C o a s t a l Oceanography Group o f t h e I n s t i t u t e o f Ocean S c i e n c e a t  Patricia  ( I.O.U.B.C., 1 9 7 2 , e t c . )  Bay has o p e r a t e d c h a i n s o f c u r r e n t meters  Howe S o u n d . 1972  i n Data Reports  i n both basins of  A s t a t i o n c l o s e t o Howe 4 was o c c u p i e d b e t w e e n November  and F e b r u a r y 1974. The d e p t h s w h i c h were m o n i t o r e d  were:  3 m ( G e o d y n e A - 8 5 0 v e c t o r a v e r a g i n g c u r r e n t m e t e r ) , 5, 1 0 , 1 5 , 2 0 , 30 and  150 m ( A a n d e r a a RCM-4 c u r r e n t m e t e r s ) .  been p u b l i s h e d by B e l l sive vector  The r e s u l t i n g  d a t a have  (1975) under t h e form o f h i s t o g r a m s and p r o g r e s -  diagrams.  These d a t a have been a n a l y z e d by B e l l  (1973) and P i c k a r d  ( 1 9 7 5 ) f r o m t h e p o i n t o f v i e w o f t h e e v o l u t i o n o f t h e Deep W a t e r erties  and by B u c k l e y  (1977) a l s o  (1977) f o r t h e c u r r e n t meter d a t a .  c a r r i e d o u t an experiment  prop-  Buckley  w i t h r a d a r - t r a c k e d drogues t o  study t h e dynamics o f t h e S u r f a c e Layer.  T y p i c a l w i n t e r p r o f i l e s o f temperature Sound a r e p r e s e n t e d i n f i g u r e 3.  and s a l i n i t y  i n Howe  They were o b t a i n e d a t s t a t i o n s  Howe 3 ( O u t e r B a s i n ) a n d Howe 4 ( I n n e r B a s i n ) o n F e b r u a r y 5 a n d 6, 1974. water  The p r o f i l e s  illustrate  t h a t t h e d e n s i t y o f t h e Howe S o u n d  i s c o n t r o l l e d by s a l i n i t y  temperature  which  i n c r e a s e s w i t h depth  that of s a l i n i t y .  i n c r e a s e s w i t h depth.  I n f i g . 3,  so t h a t i t s e f f e c t p a r t l y c o u n t e r a c t s  A t o t h e r t i m e s o f t h e y e a r , t e m p e r a t u r e may  w i t h depth over p a r t of the water  decrease  column b u t i t p l a y s a secondary  i n d e t e r m i n i n g t h e d e n s i t y o f t h e Howe S o u n d  water.  role  6  Figure 3 also homogeneous b e l o w  shows t h a t t e m p e r a t u r e a n d s a l i n i t y  are very  100 m i n t h e I n n e r B a s i n compared t o what i s f o u n d  a t s i m i l a r d e p t h i n t h e O u t e r B a s i n and compared t o what i s f o u n d i n b o t h b a s i n s a b o v e 100 m.  Pickard  (1975)  has i n d i c a t e d  that a majority of the i n l e t s of  t h e B r i t i s h C o l u m b i a m a i n l a n d c o a s t show y e a r l y v a r i a t i o n s Deep W a t e r p r o p e r t i e s .  These changes appear  processes i n v o l v i n g water Water o f a few i n l e t s ,  from t h e S t r a i t  to occur through advective  of Georgia.  I n t h e Deep  such y e a r l y v a r i a t i o n s a r e n o t apparent;  Deep W a t e r t h e r e may r e m a i n  Howe S o u n d a p p e a r s because  i n their  of i t s shallow s i l l .  the  t r a p p e d f o r more t h a n a y e a r a t a t i m e .  to c o n s t i t u t e a borderline case, Pickard  (1975)  presumably  describes the evolution of  t h e Deep W a t e r a t 2 0 0 m, a t s t a t i o n Howe 4, a s p r e s e n t i n g a saw t o o t h pattern. oxygen.  Quick changes o c c u r i n t h e s a l i n i t y ,  They a r e f o l l o w e d by slow changes w h i c h a r e a t t r i b u t e d  a d v e c t i v e p r o c e s s e s such as t u r b u l e n t ( f o r d i s s o l v e d oxygen). whether  Pickard  t o non-  t r a n s f e r and b i o c h e m i c a l processes  (1975)  indicated  t h a t i t was n o t c l e a r  t h e Deep W a t e r i n Howe S o u n d u n d e r w e n t a n n u a l c h a n g e s o r more  intermittent  Bell  ones.  (1973)  s t u d i e d Deep W a t e r r e p l a c e m e n t s i n t h e I n n e r B a s i n .  He e x a m i n e d p r i n c i p a l l y tration  temperature and d i s s o l v e d  t h e e v o l u t i o n o f t h e d i s s o l v e d oxygen  (D.O.) a n d s a l i n i t y a t d e p t h s o f 1 0 0 , 1 5 0 a n d 200 m.  w a t e r v o l u m e s u c h a s t h e Deep W a t e r o f t h e I n n e r B a s i n w h i c h from s u r f a c e exchanges  concenIn a i s isolated  a n d s u n l i g h t , D.O. v a l u e s a r e e x p e c t e d t o  decrease w i t h time under  the influence of l o c a l biochemical processes.  7  Similarly,  salinity  fresher water B e l l argued  i s expected to decrease w i t h time because  from above g e t s t u r b u l e n t l y mixed  t h a t w h e n e v e r D.0.  W a t e r showed s i g n i f i c a n t water  and  He  A t t h e 150  high r i v e r  and  (1973)  suggested  r u n o f f and  the s i l l  i n early  volume and  the  variable.  winds  by  ("Squamish w i n d s " ) .  A  of course, i s t h a t the o u t s i d e water  t o be a s d e n s e a s , o r d e n s e r  Deep W a t e r o f t h e I n n e r B a s i n . met  The  t h a t t h e s e i n f l o w s were t r i g g e r e d  s t r o n g seaward  l e v e l has  to occur  200 m l e v e l s , m a j o r i n -  t o o c c u r a t l e a s t e v e r y few y e a r s .  preliminary condition for this, found near  i n t o the Inner Basin's  i n f l o w s appeared  depth of p e n e t r a t i o n of the i n f l o w s appear  Bell  i n t h e I n n e r B a s i n ' s Deep  f o u n d i t s way  f o u n d a t t h e 100 m l e v e l ,  f r e q u e n t l y , a l l year round. flows appeared  t h e Deep W a t e r .  d e p a r t u r e s f r o m t h e i r downward t r e n d s , some  from the Outer B a s i n had  Deep W a t e r .  salinity  into  some  than  the  These c o n d i t i o n s a r e most l i k e l y  to  be  winter.  D u r i n g J u n e and J u l y 1 9 7 3 ,  B u c k l e y (1977)  L a y e r o f Howe Sound w i t h n e a r s u r f a c e p r o f i l e s n i t y and w i t h r a d a r t r a c k e d s u r f a c e drogues. o f t h e h a l o c l i n e v a r i e d b e t w e e n 0 and  studied the Surface  o f t e m p e r a t u r e and He  found that the  5 m during h i s experiment.  sali-  depth The  h a l o c l i n e was  s h a r p e s t n e a r t h e m o u t h o f t h e r i v e r a n d more  diffuse  f u r t h e r away.  I t s d e p t h v a r i e d w i t h t i m e , l o n g i t u d i n a l and  lateral  positions.  The sails  b u l k o f B u c k l e y ' s e x p e r i m e n t was  s e t b e t w e e n 0 and  f o l l o w e d a meandering  2 m.  He  made w i t h d r o g u e s  with  found that the r i v e r d i s c h a r g e  p a t t e r n over the i n l e t .  During a short experiment,  8  Buckley  used drogues w i t h s a i l s  setat different  an o u t f l o w a n d a s t r o n g r e t u r n f l o w w i t h The  c o r e s were l o c a t e d on d i f f e r e n t  their  cores  5 m, i t was o n a v e r a g e g o i n g  up i n l e t  were l a r g e f l u c t u a t i o n s c e n t e r e d  Buckley and  c u r r e n t meter s t r i n g  velocity.  accounted f o r v a r i a t i o n s i n the Further  down t h e i n l e t ,  e s t a b l i s h e d by the P a c i f i c  a t 150 m.  o f t h e c u r r e n t r e c o r d s was c o n c e n t r a t e d  c y c l e s p e r day ( B u c k l e y ,  1977).  Buckley  i n t h e band o f one t o  showed t h a t a t i d a l  model y i e l d e d a r a t i o o f t h e d i u r n a l v e l o c i t y v a r i a n c e  had  Oceano-  The s p e c t r a l  2  the s e m i - d i u r n a l v a r i a n c e  Layer.  B a s i n o f Howe Sound h a d 6 m e t e r s l o c a t e d i n  t h e u p p e r 30 m a n d o n l y o n e m e t e r b e l o w t h i s ,  o f 0.30.  o f 0.31.  The o t h e r  prism  2  (m / s e c ) t o  T h e c u r r e n t m e t e r a t 150 m y i e l d e d  c u r r e n t m e t e r s , l o c a t e d i n t h e u p p e r 30 m,  r a t i o s w h i c h w e r e q u i t e v a r i a b l e b u t a l w a y s l a r g e r t h a n 0.7.  e x a m i n i n g t h e shape o f t h e s p e c t r a , B u c k l e y  concluded  o f w i n d s d e c r e a s e d w i t h d e p t h a n d became i n s i g n i f i c a n t W i n d s o v e r Howe Sound h a v e a s t r o n g  By  that the effect a t 150 m.  d i u r n a l component w h i c h w o u l d  e x p l a i n why t h e r a t i o o f d i u r n a l t o s e m i - d i u r n a l v a r i a n c e near the surface.  there  found t h a t n e a r t h e head o f t h e i n l e t , w i n d s , t i d e s  g r a p h i c Group i n t h e I n n e r  a ratio  then  a n d f o u n d t h a t a t 3 m,  was t h e w i n d w h i c h d o m i n a t e d t h e c i r c u l a t i o n o f t h e S u r f a c e  variance  both  a t 3.6 cm/sec w h i l e a t  f i e l d which had comparable magnitudes.  The  two  Buckley  a t 4.2 cm/sec a n d a t 10 m,  near zero  v a r i a t i o n s i n the r i v e r discharge  velocity it  down i n l e t  He f o u n d  i n t h e u p p e r 5 m.  sides of the i n l e t .  examined t h e near s u r f a c e c u r r e n t meter r e c o r d s t h e c u r r e n t was o n a v e r a g e g o i n g  depths.  i slarger  9  The c u r r e n t m e t e r l o c a t e d a t 150 m r e c o r d e d ties  o f 0.15 m/sec.  (1973),  routinely  I n the c u r r e n t v e c t o r diagrams presented  velociby  Bell  d u r i n g November a n d D e c e m b e r 1 9 7 3 , t h e r e was a c o n s i s t e n t  r e s i d u a l current of the order towards the s i l l . d r i f t was f o u n d . maximum s i l l  During Notice  depth.  o f .01 m/sec  (roughly  1 km/day)  J a n u a r y a n d F e b r u a r y 1 9 7 4 , no s u c h  flowing consistent  t h a t t h e c u r r e n t m e t e r i s l o c a t e d 80 m b e l o w  I t i s not c l e a r whether the r e s i d u a l c u r r e n t i s  r e a l o r whether i t i s an a r t i f a c t  o f t h e c u r r e n t m e t e r and i t s m o o r i n g .  10  Chapter I I  New A s p e c t s o f t h e O c e a n o g r a p h i c and  Bell concerned  Current Meter  (1973), P i c k a r d  (1975) and B u c k l e y  m o s t l y w i t h t h e Deep W a t e r  B a s i n ) and t h e S u r f a c e Layer temperature  Data.  (below  sill  o f Howe S o u n d .  t h e depth range  Water renewal earlier.  Both  of the f a l l  i n the Inner  h a s b e e n o b t a i n e d i n Howe  o f 10 t o 100 m.  t h e d a t a w e r e o b t a i n e d i n November 1 9 7 3 e i t h e r a Deep W a t e r r e n e w a l .  depth,  H o w e v e r , much o f t h e  m i c r o s t r u c t u r e i n f o r m a t i o n which  Sound comes f r o m  (1977) have been  M o r e o v e r , much o f  during or shortly  t h e 10 t o 100 m d e p t h r a n g e  o f 1973 have r e c e i v e d l i t t l e  after  a n d t h e Deep attention  T h i s c h a p t e r p r e s e n t s a n d d i s c u s s e s some d a t a r e l e v a n t t o  t h e s e a s p e c t s o f t h e p h y s i c a l o c e a n o g r a p h y o f Howe S o u n d .  II.1  The I n t e r m e d i a t e Water.  The  object of this  s e c t i o n i s t o show b r i e f l y  that there are  r e g i o n s i n Howe S o u n d w h e r e t h e e v o l u t i o n o f o c e a n o g r a p h i c p r o p e r t i e s is  c o n t r o l l e d m a i n l y by h o r i z o n t a l exchanges between t h e S t r a i t o f  Georgia, the Outer study, the water Water".  B a s i n and t h e I n n e r B a s i n .  found  F o r t h e purpose  i n these r e g i o n s i s c a l l e d  The d a t a p r e s e n t e d h e r e  come f r o m  of this  the "Intermediate  the monthly  oceanographic  c r u i s e s made b y t h e I n s t i t u t e o f O c e a n o g r a p h y o f t h e U n i v e r s i t y o f British  C o l u m b i a b e t w e e n 1972 a n d 1974 ( I . O . U . B . C . , 1 9 7 2 , e t c . ) .  F i g u r e 4 shows t h e t e m p e r a t u r e and b e l o w  t i m e - s e r i e s o b s e r v e d a t 100 m  a t s t a t i o n s Howe 2 a n d Howe 3 i n t h e O u t e r B a s i n .  p r e s e n t s time s e r i e s o f temperature and s a l i n i t y a g e d b e t w e e n 20 a n d 75 m.  from each b a s i n  aver-  T h e s t a t i o n s a r e Howe 3 ( O u t e r B a s i n ) a n d  Howe 4.5 ( I n n e r B a s i n ) ( s e e f i g .  1 ) . The samples  f r o m 2 0 , 3 0 , 50 a n d  75 m w e r e a v e r a g e d w i t h w e i g h t s o f 2, 3, 4, 4 t o r e f l e c t the depth i n t e r v a l r e p r e s e n t e d by each v a l u e . time-series of temperature, s a l i n i t y , o b t a i n e d a t 100 m a n d b e l o w  Figure 5  the size of  Figure 6 presents the  sigma-t and d i s s o l v e d  oxygen  i n t h e I n n e r B a s i n (Howe 4 . 5 ) .  F i g u r e 4 shows l a r g e v a r i a t i o n s o f t e m p e r a t u r e o n a t i m e s c a l e which  i sw e l l r e s o l v e d by the monthly  rate of sampling.  The  v a r i a t i o n s a r e a r e f l e c t i o n of. those t a k i n g p l a c e i n the S t r a i t o f Georgia  ( P i c k a r d , 1975) and i l l u s t r a t e  t a k i n g p l a c e between t h e S t r a i t  the r e l a t i v e l y  free  o f G e o r g i a and t h e Outer  m a i n l y t h r o u g h t h e Queen C h a r l o t t e  exchanges  Basin,  Channel.  I n f i g u r e 5, t h e t e m p e r a t u r e  time-series  show t h a t t h e v a r i a -  t i o n s w h i c h o c c u r b e t w e e n 20 a n d 75 m i n b o t h b a s i n s f o l l o w a p a t t e r n similar  to that which  i s observed below  100 m i n t h e O u t e r B a s i n .  The  r a n g e o f t h e t e m p e r a t u r e v a r i a t i o n s a t Howe 4.5 ( I n n e r B a s i n ) i s slightly  s m a l l e r t h a n t h a t a t Howe 3 ( O u t e r B a s i n ) b u t no s i g n i f i c a n t  l a g i s o b s e r v e d b e t w e e n t h e two t i m e - s e r i e s . series of f i g .  5 also  The two s a l i n i t y  t r a c k each o t h e r q u i t e c l o s e l y .  i n s t a n c e s , l a r g e changes i n s a l i n i t y  time-  In several  a r e o b s e r v e d i n b o t h b a s i n s by t h e  same c r u i s e s a n d  t h u s t h e y may  t h a n one m o n t h .  O n l y i n f l o w s o f s a l i n e w a t e r may  in  salinity  this  occur w i t h i n a time i n t e r v a l  a n d , i n Howe S o u n d , o n l y t h e S t r a i t  s a l i n e water.  Thus t h e v a r i a t i o n s  result  one  i n increases  o f G e o r g i a may  i n s a l i n i t y and  o b s e r v e d a b o v e 75 m i n b o t h b a s i n s r e s u l t f r o m e x c h a n g e s Strait  shorter  provide  temperature with  the  o f G e o r g i a w h i c h c a n t a k e p l a c e on a t i m e s c a l e s m a l l e r  than  month.  I n f i g u r e 6, and d i s s o l v e d oxygen  the t i m e - s e r i e s of temperature, s a l i n i t y ,  a t 125 m a n d b e l o w  show p e r i o d s o f s t e a d y  s e p a r a t e d b y p e r i o d s o f l a r g e r a n d more a b r u p t c h a n g e . d e s c r i b e d as " s a w - t o o t h " by P i c k a r d  (1975).  Bell  trend  This pattern i s  (1973)  c o r r e s p o n d s t o p e r i o d s when d i f f u s i v e p r o c e s s e s d o m i n a t e  showed t h a t i t and  when t h e r e a r e i n f l o w s f r o m t h e O u t e r B a s i n , o v e r t h e s i l l  to periods  and  into  t h e I n n e r B a s i n ' s Deep W a t e r .  This pattern d i f f e r s markedly  one w h i c h was  4 a n d 5, f o r t h e O u t e r B a s i n a n d  observed i n f i g .  p a r t o f t h e I n n e r B a s i n a t 75 m a n d  sigma-t  from  the  the  above.  The p r e c e d i n g d i s c u s s i o n shows t h a t t h e I n t e r m e d i a t e W a t e r , as d e f i n e d about  i n the f i r s t  20 m a n d  paragraph of t h i s  the bottom  section,  i n the Outer Basin.  i s found between  In the Inner B a s i n , i t  i s c h o s e n t o p u t t h e l o w e r l i m i t o f t h e I n t e r m e d i a t e W a t e r a t 100 since i n f i g .  6,  t h e w a t e r a t 100 m h a d a n e v o l u t i o n m a r k e d l y  f r o m t h e w a t e r a t 125 m a n d b e l o w . Inner Basin i s therefore c a l l e d the s u r f a c e ,  different  The w a t e r a t 125 m a n d b e l o w  t h e "Deep W a t e r "  i n this  i t i s n o t c l e a r a t what d e p t h exchanges  o f G e o r g i a become l e s s i m p o r t a n t t h a n t h e v e r t i c a l  with  thesis. the  turbulent  m  i n the Near  Strait transfer  of  t h e l o c a l f r e s h water  most o f t h e f r e s h w a t e r limit for  run off. was f o u n d  Buckley  showed t h a t ,  i n t h e u p p e r 10 m.  Thus t h e upper  o f t h e I n t e r m e d i a t e W a t e r may b e s e t a t 10 m b e l o w t h e s u r f a c e  t h e purpose of t h i s  study.  Figure 7 presents a  s e c t i o n o f Howe S o u n d w h e r e t h e S u r f a c e L a y e r , and  i n June 1973,  long-channel  the Intermediate  Water  t h e Deep W a t e r a r e shown.  II.2  A Deep W a t e r r e n e w a l  In  the F a l l  o f 1973,  I n n e r B a s i n o f Howe S o u n d . temperature  i n the F a l l  a Deep W a t e r r e n e w a l  renewal  occurred i n the  On November 20 a n d 2 1 , 1 9 7 3 a c r u i s e made  m i c r o s t r u c t u r e observations i n the Inner Basin.  i n t e r p r e t a t i o n of the r e s u l t i n g requires  o f 1973.  data  (presented i n the next  The chapters)  t h a t some o f t h e i n f o r m a t i o n a v a i l a b l e f o r t h e Deep W a t e r be examined  first.  F i g u r e s 8, 9 a n d 10 p r e s e n t l o n g - c h a n n e l  s e c t i o n s o f temper-  a t u r e , s a l i n i t y a n d d i s s o l v e d o x y g e n (D.0.) o b t a i n e d w i t h b o t t l e on S e p t e m b e r 2 0 , 1 9 7 3 , o n November 1 3 , 1 9 7 3 a n d o n J a n u a r y (I.O.U.B.C., 1 9 7 3 ) .  F i g u r e 11 p r e s e n t s t h e t e m p e r a t u r e  N-S c o m p o n e n t o f t h e v e l o c i t y meter c h a i n l o c a t e d near to  November 1 5 .  ward f l o w .  North  casts  2 2 , 1974  r e c o r d and t h e  r e c o r d o b t a i n e d a t 150 m b y a c u r r e n t  s t a t i o n Howe 4, f o r t h e p e r i o d o f O c t o b e r  25  P o s i t i v e c u r r e n t v a l u e s i n f i g . 11 i n d i c a t e a n o r t h l i e s approximately  i n an u p - i n l e t d i r e c t i o n  (fig.l).  The Deep W a t e r d i s t r i b u t i o n o f S e p t e m b e r 2 0 , 1973 t y p i c a l o f t h a t w h i c h was (I.O.U.B.C., 1 9 7 3 ) .  e n c o u n t e r e d d u r i n g the p r e v i o u s s i x months  I t i s interesting  v a l u e s are found a l o n g the bottom pleth.  to n o t i c e that  are found i n the b o t t l e  c o n t r a s t s o f up  The m o n t h l y  density  o f 7.9  A t e m p e r a t u r e minimum i s f o u n d a t 100 m  t o 8.0  e r a t u r e a t 75 m c h a n g e d  °C  C° 1973).  (fig.8). stayed i n  s i n c e t h e p r e v i o u s J u n e w h i l e t h e temp-  f r o m c o o l e r t o warmer t h a n t h i s  A t 125 m a n d b e l o w ,  D.O.  difference  c r u i s e s show t h a t t h e t e m p e r a t u r e a t 100 m h a s  the v i c i n i t y  1973).  t o 0.09  cast data (I.O.U.B.C,  T h e y a r e o f o p p o s i n g s i g n a n d no m e a s u r a b l e r e s u l t s f r o m them.  the lowest  p r o f i l e r a t h e r t h a n any o t h e r i s o -  A l s o , a l o n g a same d e p t h l e v e l ,  a n d 0.009 °/oo  (fig.9) i s  the t i m e - s e r i e s i n d i c a t e  a b r u p t change i n p r o p e r t y has o c c u r r e d (see f i g . 6 )  (I.O.U.B.C,  t h a t no  large  or  s i n c e the p r e v i o u s  February.  The November 1 3 , 1973 Deep W a t e r d i s t r i b u t i o n m a r k e d l y from t h a t o f September. two  d i s t i n c t water masses.  One  The  I n n e r B a s i n i s now  p r o p e r t i e s a s t h e w a t e r w h i c h was  a n d w i t h D.O. now  called  t h a n 8.3  The  C,  i n the Outer B a s i n ,  1973).  less  s a l i n e t h a n 30.5 ml/1).  A t Howe 4,  called  t h e "New  Water"  parts  /oo  This water i s  towards  i t o c c u p i e s the whole w a t e r column different  to  t h e same o c e a n o g r a p h i c  o t h e r w a t e r mass i s f o u n d b e l o w  I t s properties are d i s t i n c t l y  W a t e r a n d i t i s now  I t has  t h a n 2.5  a n d a b o v e 50 m t h r o u g h t h e I n n e r B a s i n . and  o c c u p i e d by  p r e v i o u s l y found i n the deepest  concentrations smaller  the " O l d Water".  differs  m a s s o c c u p i e s t h e d e p t h r a n g e o f 50  200 m i n t h e u p - i n l e t p a r t o f t h e b a s i n .  of the Inner B a s i n ( c o l d e r  (fig.9)  the  200  m  sill  (I.O.U.B.C,  from those of the Old  (temperature higher than  8.5  °C,  s a l i n i t y higher  t h a n 2.4  ml/1).  The  t h a n 30.5  °/oo,  sigma-t v a l u e  D.O.  concentration  higher  of b o t h water masses i s between  3 23.67 and too  23.70 kg/m  s m a l l t o be The  and  t h e d e n s i t y s t r a t i f i c a t i o n b e l o w 100  accurately  J a n u a r y 22,  presents  two  t h e D.O.  distribution.  1974  Deep W a t e r d i s t r i b u t i o n  d i s t i n c t water masses. The  the  cores  d i f f e r e n c e has 100 D.O.  m and  values  at that  The  d e c r e a s e d f r o m 0.5  d e c r e a s e d f r o m 0.10  less,  This  the  are higher,  indicating  two  one  well in  w a t e r masses i s  t o 0.3  °/oo  C°  t o 0.08  are  lower  and  °/oo.  the At  salinity depths  t h a t exchanges have been  the  continuing  level.  t h e Deep W a t e r r e n e w a l ,  i n s t a l l e d b e l o w 30 m.  t h e 150  Buckley  Howe 4  m c u r r e n t m e t e r was  (1977) , u s i n g o n l y the  the  essentially  b e t w e e n November 9 and  13.  g r e s s i v e v e c t o r d i a g r a m s ( B e l l , 1975) i n s t e a d of the u s u a l down-inlet this chapter.  velocity  and  During  show a n e t  t h e N-S  pro-  up-inlet current mentioned  earlier  component o f t h e  current  the temperature r e c o r d obtained  l o c a t e d a t 150  place  t h i s p e r i o d , the  " d r i f t " w h i c h was  F i g . 11 p r e s e n t s  only  velocity  r e c o r d o f t h i s m e t e r , d e d u c e d t h a t t h e Deep W a t e r i n f l o w t o o k  in  of  t h a n i n J a n u a r y and  In the c u r r e n t meter c h a i n l o c a t e d near s t a t i o n during  still  temperature d i f f e r e n c e between  C°  s a l i n i t y values  (fig.10)  shows p a r t i c u l a r l y  c o n t r a s t between the  t h a n i n November ( f i g . 9 ) . has  is  estimated.  smaller two  m  from the c u r r e n t  meter  m.  F i g u r e 11  shows t h a t , s t a r t i n g  w a t e r " p u l s e s " o c c u r r i n g o n c e a day  O c t o b e r 27,  a t 150  t h e r e a r e warm  m u n t i l O c t o b e r 31.  The  o n l y p o s s i b l e s o u r c e o f w a t e r warmer coming from t h e Outer B a s i n  t h a n 8.4  ( f i g . 8 and 9 ) .  t h e Deep W a t e r r e n e w a l s t a r t e d b e f o r e  C i s c l e a r l y New  Water  T h u s , f i g . 11 shows  o r o n O c t o b e r 27.  that  I t i s not  c l e a r w h e t h e r t h e warm w a t e r was a d v e c t e d h o r i z o n t a l l y o r v e r t i c a l l y past  t h e c u r r e n t m e t e r a n d no e s t i m a t e  of the volume of the i n f l o w  c a n b e made f r o m t h e c u r r e n t m e t e r r e c o r d s  alone.  S t a r t i n g November 2, t h e 150 m c u r r e n t m e t e r becomes inantly  i m m e r s e d i n warm w a t e r .  variations pattern. further late  The c u r r e n t v e l o c i t y  than p r e v i o u s l y and o f t e n p r e s e n t s  larger  a s o r t of "square  The r e a s o n s f o r t h i s a r e n o t c l e a r . i n f l o w s are o c c u r r i n g a t that time,  shows  predom-  One  can speculate  b u t one c a n a l s o  wave" that  specu-  t h a t t h e Deep W a t e r i s r e s p o n d i n g t o a c h a n g i n g p a t t e r n o f  forcing functions  (surface winds, t i d e s ,  r i v e r r u n o f f ) and t h a t t h e  150 m c u r r e n t m e t e r h a s become i m m e r g e d p r e d o m i n a n t l y i n New W a t e r a r e s u l t o f t h i s r a t h e r t h a n a s a r e s u l t o f new  as  inflows.  I n summary, t h e o c e a n o g r a p h i c t i m e - s e r i e s show t h a t a Deep Water renewal o c c u r r e d  b e t w e e n S e p t e m b e r a n d November 1 9 7 3 .  current meter temperature record had  a t 150 m i n d i c a t e s t h a t  a t l e a s t s t a r t e d o n O c t o b e r 27.  record  i s of l i t t l e  use.  The New W a t e r o c c u p i e s  t h e Deep W a t e r a n d , n e a r t h e c e n t e r Inner Basin  clear  were o b t a i n e d  that  of the channel,  data which are presented  r e n e w a l had t a k e n  place.  velocity  the part of the  Some o f t h e t e m p e r -  i n the f o l l o w i n g  s h o r t l y a f t e r November 1 8 , 1 9 7 3 .  these data were o b t a i n e d  the renewal  t h e l o w e r 200 m o f  l o c a t e d b e t w e e n Howe 4 a n d t h e s i l l .  ature microstructure chapters  The c u r r e n t m e t e r  The  a f t e r the bulk  I t i s now  o f t h e Deep W a t e r  Chapter I I I  M i c r o s t r u c t u r e methods and d a t a p r o c e s s i n g .  III.l  P r o b e s and  In  resolution.  the c o u r s e of p r e v i o u s work i n m i c r o s t r u c t u r e ,  has o f t e n been f e l t  f o r a set of l i g h t ,  microstructure profilers. was  The  s i m p l e and r u g g e d  T h i s was  to  The  o r more c o m p l e x i n s t r u m e n t s .  t e m p e r a t u r e m i c r o s t r u c t u r e p r o f i l e r s was  i d e n t i c a l probes nicknamed  Osborn (1977).  The  resulted  The  difficult  d e s i g n of  i n 1972  at  the  spherical  floats  probes are d e s c r i b e d i n d e t a i l  A s c h e m a t i c d r a w i n g o f one  i s shown i n f i g .  The  t h e r m i s t o r i s a m e t a l oxyde microbead  with  t y p i c a l d i a m e t e r o f 150 m i c r o n s , c o a t e d w i t h a f i l m  of  w i t h a t h i c k n e s s of about  insulation  15 m i c r o n s f o r e l e c t r i c a l  the occurrence of e l e c t r i c a l  leaks into  t h e r m i s t o r s u p p o r t arms ( n o t t h e m i c r o b e a d s )  The  12.  p r o b e s p r o v i d e a s u p p o r t f o r a t h e r m i s t o r b r i d g e and  its electronics.  To r e d u c e  light  i n a set of three  "Pumpkin" f o r the orange  which p r o v i d e s t h e i r buoyancy. in  and  initiated  probes  temperature  m i c r o s t r u c t u r e by making s i m u l t a n e o u s p r o f i l e s .  U n i v e r s i t y of B r i t i s h Columbia  temperature  f i r s t m o t i v a t i o n i n u s i n g such  to i n v e s t i g a t e the h o r i z o n t a l c h a r a c t e r i s t i c s of  do w i t h e a r l i e r  the need  Paralene-C  sea water,  were c o a t e d w i t h  (fig.12)  the glyptol.  frequency response of such a t h e r m i s t o r moving i n a  has been s t u d i e d by L u e c k , Hertzman and O s b o r n ( 1 9 7 7 ) .  a  For a  fluid  typical  v e l o c i t y o f 20 c m / s e c , t h e i r  c a l c u l a t i o n s i n d i c a t e t h e 3 dB p o i n t i n  s p a t i a l r e s o l u t i o n t o b e c l o s e t o 2 cm.  The of f i n e  present  study  c o n s i s t s o f an i n v e s t i g a t i o n o f t h e types  s t r u c t u r e a n d m i c r o s t r u c t u r e f e a t u r e s e n c o u n t e r e d i n Howe  Sound a n d o f t h e i r h o r i z o n t a l v a r i a b i l i t y . i s n o t based on q u a n t i t a t i v e e s t i m a t e s vertical  temperature gradient.  The a n a l y s i s o f t h e d a t a  of the t o t a l variance  Therefore,  the individual  of the  frequency  r e s p o n s e o f e a c h t h e r m i s t o r was n o t m e a s u r e d a n d no a t t e m p t h a s b e e n made t o c o r r e c t t h e h i g h f r e q u e n c y  The  roll-off.  t h e r m i s t o r was p a r t o f a W h e a t s t o n e b r i d g e .  The e l e c t r o -  n i c package o f t h e probe generated a temperature s i g n a l and t h e time derivative of this signal.  These were r e l a y e d t o t h e s u r f a c e  a S i p p i c a n XWL ( E x p e n d a b l e W i r e L i n k ) u s i n g s u r f a c e , these and  digitized  a typical per  s i g n a l s were r e c o r d e d  through  I R I G FM c h a n n e l s .  At the  on tape t o be l a t e r p l a y e d  a t a r a t e o f 250 s a m p l e s p e r s e c o n d p e r c h a n n e l .  back For  s i n k i n g r a t e o f 20 c m / s e c , t h i s c o r r e s p o n d s t o 12.5 s a m p l e s  cm.  The  noise present  i n t h e s i g n a l s has been e s t i m a t e d  from t h e  deep p a r t s o f t h e p r o f i l e s w h e r e no m e a n i n g f u l s i g n a l c o u l d b e M o s t o f t h e n o i s e v a r i a n c e was i n t h e h i g h e r instrument,  a t wave n u m b e r s h i g h e r  t h a n 2 cm  frequency  detected.  range o f t h e  A t depths  greater  t h a n 100 m, i t i n c r e a s e d a p p r e c i a b l y w i t h d e p t h b e c a u s e o f t h e i n c r e a s i n g l e n g t h o f t h e XWL l i n k . are:  N e a r 150 m, t y p i c a l rms n o i s e  0.01 C° i n t h e t e m p e r a t u r e c h a n n e l  channel.  values  a n d 0.03 C°/m i n t h e g r a d i e n t  During  t h e F e b r u a r y 1974 c r u i s e , t h e m i c r o s t r u c t u r e  were used i n p a i r s . o f 3, 10 a n d 20 m. before The  They were r e l e a s e d w i t h a h o r i z o n t a l s e p a r a t i o n They f e l l  freely  t o a d e p t h o f 150 t o 200 m  r e l e a s i n g some b a l l a s t w e i g h t a n d f l o a t i n g b a c k t o t h e s u r f a c e .  probes surfaced w i t h separations  of t h e probes a t r e c o v e r y launch  (see Table I ) .  b e t w e e n 1 a n d 75 m.  During  w i t h i n one m i n u t e o f e a c h  III.2  the descent,  struct  processing.  The  i n processing  step  rough v e r t i c a l  ture s i g n a l versus  the probes probably  time.  stayed  r e a c h e d t h e d e p t h o f 100 m  the d i g i t i z e d  d a t a was t o c o n -  temperature p r o f i l e s by p l o t t i n g  the tempera-  These p r o f i l e s were t h e n compared w i t h  of temperature versus  a Bissett-Berman  spacing  other.  Method o f d a t a  first  The  d i d not c o r r e l a t e with the spacing at  w i t h i n 3 t o 40 m o f e a c h o t h e r a n d t h e y  files  probes  depth obtained  pro-  a t t h e same l o c a t i o n w i t h  9060 s e l f - c o n t a i n e d STD r e c o r d e r .  Salient features  of t h e p r o f i l e s were matched and t h e i r depths and t e m p e r a t u r e s on t h e STD c h a r t w e r e n o t e d .  By  a s s u m i n g t h e Pumpkin s i n k i n g r a t e t o be c o n s t a n t , t h e  matched f e a t u r e s p r o v i d e d (± 5 %•).'  a d e p t h s c a l e w i t h an a c c u r a c y  When t h e P u m p k i n s h a d b e e n u s e d i n p a i r s ,  the analysis  r e q u i r e d y e t a f i n e r match o f t h e depth s c a l e s so t h a t smaller  than s e v e r a l metres c o u l d be p a i r e d w i t h o u t  of ± 3 m  features  ambiguity.  For  this,  two s a l i e n t  f e a t u r e s o f one p r o f i l e were a s s i g n e d  depths as t h e e q u i v a l e n t f e a t u r e s on t h e o t h e r and  t h e same  p r o f i l e of the pair  t h e d e p t h s c a l e was r e c o n s t r u c t e d b y l i n e a r  interpolation.  The r e s i s t a n c e o f t h e t h e r m i s t o r s d e c r e a s e s a p p r o x i m a t e l y e x p o n e n t i a l l y when t e m p e r a t u r e i n c r e a s e s .  The e x p o n e n t i a l  c i e n t o f t h i s r e s p o n s e was known a n d i t was u s e d m a t c h e d f e a t u r e s o f t h e STD p r o f i l e  coeffi-  together with the  to construct a temperature  cali-  b r a t i o n w i t h a n a c c u r a c y o f + 0.3 C° i n t h e r a n g e o f 6 t o 9 °C.  The g a i n o f t h e d i f f e r e n t i a t o r paring  i t s s i g n a l with the temperature s i g n a l .  calibration,  the differentiator  i n g r a t e were used into a vertical  Overall  circuit  g a i n and t h e e s t i m a t e d  to scale the d i f f e r e n t i a t e d  temperature gradient  Then t h e t e m p e r a t u r e  temperature  sink-  signal  (°C/m) w i t h a n a c c u r a c y o f + 1 0 % .  profiles:  For tized  c i r c u i t was c h e c k e d b y com-  c o n s t r u c t i n g o v e r a l l p r o f i l e s o f each drop, t h e d i g i -  t e m p e r a t u r e and g r a d i e n t  points per channel.  d a t a were grouped  Each b l o c k contained  0.4 m o f t h e w a t e r c o l u m n .  i n blocks  i n f o r m a t i o n from  o f 512 about  F o r e a c h b l o c k , a mean t e m p e r a t u r e , a  mean t e m p e r a t u r e g r a d i e n t a n d a rms t e m p e r a t u r e g r a d i e n t w e r e c a l c u lated.  E a c h o v e r a l l p r o f i l e c o n s i s t s o f up t o 550 o f t h e s e  p l o t t e d w i t h the depth s c a l e obtained fashion.  i n the previously  values  described  E x a m p l e s o f s u c h p r o f i l e s a r e f o u n d i n f i g u r e s 14 t o 2 0 .  -  Detailed  profiles:  I t was a l s o p o s s i b l e t o p l o t t h e o r i g i n a l d i g i t i z e d of t e m p e r a t u r e and g r a d i e n t  s c a l e d i n °C a n d °C/m  i b r a t i o n method a s f o r t h e o v e r a l l p r o f i l e . before  using the c a l i b r a t i o n ,  the gradient  a s y n t h e t i c temperature s i g n a l .  T h i s was  using  However, s i g n a l was  t h e same  i n this  T h e n , t h e new  s i g n a l were  t e m p e r a t u r e s i g n a l and t h e g r a d i e n t  5 to 1 m per inch.  The s i g n a l was  By t h i s method,  t e m p e r a t u r e s i g n a l was v i r t u a l l y t h a n 0.005 C° o v e r s e p a r a t i o n s  into  compared w i t h t h e o r i g i n a l o f f s e t was  the c a l i b r a t i o n .  cal-  case,  integrated  t e m p e r a t u r e s i g n a l and t h e e f f e c t o f t h e g r a d i e n t  using  signal  removed. scaled  then p l o t t e d with s c a l e s of  the high frequency  noise  of the  removed and a r e s o l u t i o n o f b e t t e r  o f a f e w cm was r o u t i n e l y  achieved.  E x a m p l e s o f t h i s a r e f o u n d i n f i g . 21 t o 2 4 .  III.3  Summary o f t h e d a t a .  Two filers  c r u i s e s w e r e made w i t h  i n Howe S o u n d .  T h e y w i l l be d i s c u s s e d  III.3a)  Here, the r e s u l t i n g data i n more d e t a i l s  are b r i e f l y  pro-  presented.  i n C h a p t e r s I V a n d V.  The November 1973 c r u i s e :  The f i r s t  c r u i s e was made b e t w e e n November 19 a n d 2 3 , 1 9 7 3 .  S e v e n P u m p k i n d r o p s w e r e made. 13.  the Pumpkin m i c r o s t r u c t u r e  T h e i r l o c a t i o n s a r e shown i n f i g u r e  The r e s u l t i n g o v e r a l l p r o f i l e s a r e p r e s e n t e d  i n f i g . 14 t o 2 0 .  T a b l e I I g i v e s t h e v a l u e s o f . t h e mean s q u a r e t e m p e r a t u r e g r a d i e n t found i n each drop  (not c o r r e c t e d f o r the l i m i t e d  response of the i n -  s t r u m e n t s ) t o g e t h e r w i t h t h e l o c a t i o n a n d t i m e a t w h i c h e a c h d r o p was made.  N o t i c e t h a t D r o p s P-10 a n d P-12 t o P-15 c o n s t i t u t e a t i m e  s e r i e s o f p r o f i l e s made a t s t a t i o n Howe 4.  Two d e t a i l e d p r o f i l e s  f r o m D r o p P-12 a n d two f r o m D r o p P-13  a r e p r e s e n t e d i n f i g u r e s 21 t o 24.  D u r i n g t h e November 1 9 7 3 c r u i s e , w e r e a l s o made a n d t h e y r e s u l t e d channel sections.  a l a r g e number o f STD c a s t s  i n s e v e r a l c r o s s - c h a n n e l and l o n g -  One l o n g - c h a n n e l s e c t i o n i s p r e s e n t e d i n f i g .  25  a n d c r o s s c h a n n e l s e c t i o n s made a t Howe 4 a n d Howe 4.7 a r e p r e s e n t e d in fig.  I I I . 3 b)  26 a n d 2 7 .  The F e b r u a r y 1974 c r u i s e :  The and  8, 1 9 7 4 .  second  cruise  i n Howe Sound was made b e t w e e n F e b r u a r y 4  T h i s t i m e , b o t h b a s i n s were v i s i t e d  two p r o b e s w e r e u s e d  simultaneously.  and, f o reach  Table I l i s t s  w h i c h w e r e made i n F e b r u a r y 1 9 7 4 t o g e t h e r w i t h t h e i r  drop,  a l l the drops time and l o c a t i o n  and w i t h t h e s e p a r a t i o n o f t h e p r o b e s a t l a u n c h a n d a t r e c o v e r y . F i g . 28 shows t h e l o c a t i o n o f t h e d r o p s o n a map o f Howe S o u n d . all  p r o f i l e s o f the drops a r e presented i n f i g .  lists,  f o reach drop, the temperature  29 t o 3 3 .  The o v e r Table I I I  change found a c r o s s t h e I n t e r -  m e d i a t e W a t e r a n d t h e mean s q u a r e g r a d i e n t m e a s u r e d t h r o u g h i t (without c o r r e c t i o n f o r the response of the probes).  F i g u r e s 34 t o 37 p r e s e n t t h e deep p a r t o f t h e p r o f i l e s o f d r o p s 7 t o 10 w i t h a n e x p a n d e d t e m p e r a t u r e out t h e s m a l l temperature c o n t r a s t s found  Fig.  38 c o m p a r e s STD p r o f i l e s  a n d o n F e b r u a r y 4, 1974 a t Howe 4.  scale i n order to bring there.  t a k e n on J a n u a r y 2 2 , 1974  F i g . 39 shows a l o n g c h a n n e l STD  s e c t i o n made i n t h e I n n e r B a s i n d u r i n g t h e F e b r u a r y 1 9 7 4 c r u i s e a n d fig.  40 shows a c r o s s - c h a n n e l s e c t i o n made a t Howe 4.  Chapter IV  Temperature S t r u c t u r e  i n Howe S o u n d  i n November 1 9 7 3 a n d F e b r u a r y 1 9 7 4  The " P u m p k i n " m i c r o s t r u c t u r e  profilers yielded  about t h e s t r u c t u r e o f t h e d i s t r i b u t i o n tens the  of temperature a t scales of  o f m e t r e s a s w e l l a s a t s c a l e s o f a f e w cm. overall  In this  s t r u c t u r e o f the temperature d i s t r i b u t i o n  i s e x a m i n e d b y means o f l o n g - c h a n n e l  information  and c r o s s - c h a n n e l  chapter,  i n Howe S o u n d sections of  temperature p r o f i l e s .  Much o f t h e s t r u c t u r e s r e v e a l e d b y t h e p r o f i l e s  b e l o n g t o what G a r g e t t  (1976) c a l l s  ture  (see a l s o s e c t i o n 1.1).  provide  profiles  from t h e s c a l e s of  the larger scale picture  provided  profiles.  T e m p e r a t u r e s t r u c t u r e i n November 1 9 7 3 .  Six section  S e c o n d l y , t h e rms g r a d i e n t  and p u t t i n g i t i n t o  the temperature  IV.1  s t r u c t u r e " o f tempera-  a c r u d e way o f t a k i n g some i n f o r m a t i o n  microstructure by  the "fine  Pumpkin o v e r a l l  profiles  ( f i g . 2 5 ) a n d two c r o s s - c h a n n e l  a r e u s e d h e r e t o show t h e d i s t r i b u t i o n ture gradient  i n the Inner Basin  B o t t l e cast data  ( f i g . 14 t o 2 0 ) , o n e STD s e c t i o n s  long-channel  ( f i g . 26 a n d 2 7 )  o f t e m p e r a t u r e a n d rms t e m p e r a -  o f Howe S o u n d i n November 1 9 7 3 .  c o l l e c t e d o n November 1 3 , 1 9 7 3 ( f i g . 9)  showed t h a t  the water p r e s e n t b e f o r e t h e r e n e w a l , c a l l e d O l d Water,  h a d t e m p e r a t u r e s l o w e r t h a n 8.4 °C w h i l e c a l l e d New W a t e r ,  the recently arrived  h a d t e m p e r a t u r e s o f 8.6 °C o r m o r e .  A t s t a t i o n Howe 3.8, j u s t  inside  the s i l l ,  P - l l was made o n November 2 1 , 1 9 7 3 ( p r o f i l e fig.13).  Below  over t h e whole  t h e Pumpkin  i n fig.15,  drop  location i n  20 m, t e m p e r a t u r e s b e t w e e n 8.6 a n d 8.8 °C a r e f o u n d profile,  indicating  t h a t New W a t e r i s p r e s e n t t h e r e .  B e t w e e n 20 a n d 80 m, t h e r e a r e many l a y e r s o f v a r y i n g with  water,  temperature  t h i c k n e s s e s o f 1 t o 10 m.  A t s t a t i o n Howe 4, a c r o s s - c h a n n e l STD s e c t i o n was made (fig.26).  T h e p r o f i l e made o n t h e s o u t h - e a s t e r n s i d e o f t h e c h a n n e l  shows t e m p e r a t u r e s o f 8.6 t o 8.8 °C e v e r y w h e r e that this side of the i n l e t  b e l o w 30 m,  i s o c c u p i e d b y New W a t e r .  indicating  The p r o f i l e  made o n t h e n o r t h - w e s t e r n s i d e o f t h e c h a n n e l shows w a t e r o f 8.3 t o 8.5 °C.between 75 a n d 175 m, i n d i c a t i n g p a r t o f t h e water column. b y New W a t e r .  t h a t O l d Water o c c u p i e s t h a t  The r e s t o f t h e w a t e r c o l u m n  i s occupied  T h e p r o f i l e made i n t h e c e n t e r o f t h e c h a n n e l a l s o  shows O l d W a t e r i n t h e same d e p t h r a n g e w i t h a 20 m t h i c k  layer of  New W a t e r n e a r 100 m d e p t h .  D r o p s P-10 a n d P-12 t o P-15 w e r e a l s o made a t Howe 4, n e a r the c e n t r e o f t h e c h a n n e l ( f i g . 1 4 and f i g . 1 6 P-15 in  w e r e made a t h o u r l y i n t e r v a l s  t o 20).  (Table I I ) .  Drops  On t h e s e  P-12 t o  profiles,  t h e d e p t h r a n g e o f 30 t o 100 m, t h e r e a r e many t e m p e r a t u r e  t i o n s a t s c a l e s o f 1 t o 30 m.  Even t h e t h i c k e r  be t r a c e d o n two s u c c e s s i v e p r o f i l e s .  "layers" often  variacannot  I n some c a s e s , t h e t e m p e r a t u r e  of the " l a y e r s "  At  a s s o c i a t e s them w i t h O l d W a t e r o r New W a t e r .  s t a t i o n Howe 4.3, a n o t h e r  made ( n o t shown h e r e ) . and  STD c r o s s - c h a n n e l s e c t i o n was  I n i t , New W a t e r was f o u n d  a b o v e 100 m; i n b e t w e e n t h e r e was O l d W a t e r .  made n e a r t h e S-E s i d e o f t h e c h a n n e l , 75 a n d 150 m o n l y .  side of the channel  t h e O l d W a t e r was f o u n d  (fig.20).  I n a l l these  o n l y b e l o w 200 m a n d a b o v e 50 m.  P-16  or "old".  p r o f i l e s , New W a t e r was B e t w e e n 50 a n d 75 m, c l a s s i f i e d as  B e t w e e n 30 a n d 75 m, t h e t e m p e r a t u r e  looked very  between  ( f i g . 2 7 ) a n d D r o p P-16 was made n e a r t h e S-E  t h e w a t e r o n t h e STD p r o f i l e s c o u l d n o t b e r e a d i l y "new"  I n t h e STD p r o f i l e  A t s t a t i o n Howe 4.7, o n e STD p r o f i l e was made o n  each s i d e o f t h e channel  a g a i n found  o n l y b e l o w 200 m  similar  p r o f i l e o f drop  t o t h e p r o f i l e s o b t a i n e d a t s t a t i o n Howe 4  ( s e e f o r i n s t a n c e P-13 i n f i g . 1 9 ) .  I n D r o p s P-10 t o P - 1 6 , two a s p e c t s o f t h e rms g r a d i e n t files  strike at first  "bursts" or "patches" Secondly, little occur  Firstly  t h e rms g r a d i e n t o c c u r s i n  w h i c h appear t o be a t most a few m e t r e s  t h e r e a r e " q u i e t " r e g i o n s w h e r e , f o r up t o 50 m,  rms g r a d i e n t i s f o u n d .  The r e g i o n s w i t h l i t t l e  i n r e g i o n s where t h e temperature  Examination sharp  glance.  temperature  pro-  i s uniform with  thick.  very  rms g r a d i e n t depth.  o f a n y o f t h e p r o f i l e s a l s o r e v e a l s t h a t some  c h a n g e s a r e a c c o m p a n i e d b y no l a r g e rms g r a d i e n t  v a l u e s a n d a l s o t h a t some m i n o r t e m p e r a t u r e  changes (where t h e l o c a l  mean g r a d i e n t i s p e r h a p s w e a k e r ) show v e r y h i g h rms g r a d i e n t intensities.  Table  I I presents  t h e mean s q u a r e g r a d i e n t v a l u e s  found i n  each drop below ~*3 o 25 x 10  a b o u t 20 m.  The a v e r a g e v a l u e f o r a l l d r o p s i s  2  ( C/m)  .  The v a l u e s f o u n d i n i n d i v i d u a l  drops v a r y from  this  v a l u e b y up t o a f a c t o r o f t w o . M o s t o f t h e v a r i a n c e o f t h e g r a d i e n t comes f r o m t h e u p p e r  100 m, i n t h e r e g i o n w h e r e t h e r e a r e a l s o many  temperature v a r i a t i o n s .  Near  a n d p a t c h e s o f rms g r a d i e n t . signif icantly sition  IV.2  deeper  200 m, some d r o p s show a t e m p e r a t u r e U n f o r t u n a t e l y , none o f t h e p r o b e s  than t h i s .  On t h e STD p r o f i l e s ,  rise  went  there i s a tran-  f r o m O l d W a t e r t o New W a t e r n e a r 200 m.  Temperature  s t r u c t u r e i n F e b r u a r y 1974.  D u r i n g t h e s e c o n d m i c r o s t r u c t u r e c r u i s e i n Howe S o u n d , b e t w e e n F e b r u a r y 4 a n d 8, 1 9 7 4 , b o t h b a s i n s w e r e v i s i t e d a n d e a c h was  made w i t h  lateral  two p r o b e s i n a n e f f o r t  recovery are l i s t e d here. one  a)  t o g a i n some i n f o r m a t i o n o n t h e  extent of the microstructure patches.  made; t h e i r p o s i t i o n ,  drop  Nine double drops were  time and separation of t h e probes a t launch and  i n Table I .  Only f i v e double p r o f i l e s  These a r e Drop 6 t o Drop 10.  are presented  One STD l o n g - c h a n n e l s e c t i o n a n d  c r o s s - c h a n n e l STD s e c t i o n a t Howe 4 w e r e t a k e n .  Recent  e v o l u t i o n o f w a t e r p r o p e r t i e s i n Howe S o u n d :  F i g u r e 38 c o m p a r e s STD p r o f i l e s made J a n u a r y 2 2 , 1 9 7 4 a n d F e b r u a r y 4, 1974 ( t w o w e e k s a p a r t ) i n t h e O u t e r B a s i n a n d i n t h e I n n e r B a s i n a t Howe 4.5.  F i g . 38 shows t h a t a s i g n i f i c a n t  temperature  d e c r e a s e h a s t a k e n p l a c e a b o v e 100 m i n t h e two w e e k s w h i c h  preceded  the  February microstructure cruise.  I n the Inner Basin, a  temperature decrease has o c c u r r e d i n t h e upper Deep W a t e r , ature.  t h e STD p r o f i l e s  60 t o 70 m.  r e v e a l no s i g n i f i c a n t  changes  The d i s c u s s i o n p r e s e n t e d i n c h a p t e r I I about  Water i n d i c a t e s  similar In the i n temper-  theIntermediate  t h a t such a t e m p e r a t u r e change o c c u r r e d because t h e  f o r m e r I n t e r m e d i a t e W a t e r h a s b e e n r e p l a c e d b y some new, c o l d e r  It  i s interesting  at this point  to mention  g r a p h i c c r u i s e a l s o v i s i t e d Howe Sound o n M a r c h 1974).  I t revealed  t h a t no m a j o r  s t r u c t u r e o f t h e w a t e r column cruse.  b)  t h a t an oceano-  1 5 , 1974 ( I . O . U . B . C ,  change i n t h e o v e r a l l  temperature  h a d o c c u r r e d s i n c e t h e F e b r u a r y 1974  I n t h e Deep W a t e r b e l o w  150 m, t h e l o w e s t t e m p e r a t u r e  f r o m t h e h i g h e s t o n e b y 0.17 C ° . 1974  water  differe  T h i s c o m p a r e s t o 0.3 C° i n J a n u a r y  a n d 0.5 C° i n November 1 9 7 3 .  Temperature  structure  i n the Outer  Basin:  On F e b r u a r y 5, 1 9 7 4 , f o u r d o u b l e P u m p k i n d r o p s a n d f o u r STD c a s t s w e r e made i n R a m i l l i e s C h a n n e l  (Outer B a s i n , f i g . l ) .  o v e r a l l p r o f i l e o f Drop 6 has been p r o c e s s e d ( f i g . in  fig.  29, l o c a t i o n  2 8 ) . The STD a n d P u m p k i n p r o f i l e s w e r e made s e v e r a l  a p a r t and d i f f e r  Only the  o n l y a t s c a l e s o f 5 t o 10 m, n e a r t h e l i m i t  shown  hours of the  s p a t i a l r e s o l u t i o n o f t h e STD.  In files  o r d e r t o make c o m p a r i s o n s e a s i e r ,  o f Drop 6 have been p u t back  have been o f f s e t  t o back.  f r o m e a c h o t h e r b y 1.0 C ° .  p r o f i l e accompanies  the l e f t  t h e rms g r a d i e n t p r o -  The t e m p e r a t u r e The l e f t  temperature p r o f i l e .  profiles  rms g r a d i e n t  The Pumpkins were  l a u n c h e d w i t h a s e p a r a t i o n o f 20 m. indicates  Table I (discussed i n Chapter I I I )  that, d u r i n g the descent, the separation of the probes  pro-  b a b l y s t a y e d b e t w e e n 10 a n d 40 m.  D r o p 6 ( f i g . 2 9 ) shows many a b r u p t t e m p e r a t u r e  changes and  l o c a l temperature i n v e r s i o n s w i t h r e s p e c t t o t h e main trend. were n o t v i s i b l e on t h e t e m p e r a t u r e p r o f i l e s probe.  obtained with  t h e STD  C a r e f u l e x a m i n a t i o n o f t h e two t e m p e r a t u r e p r o f i l e s  shows t h a t d i f f e r e n c e s b e t w e e n t h e two o c c u r e s s e n t i a l l y smaller than 2 m (the p r o f i l e s  The  profiles  These  o f Drop 6  at scales  a r e made f r o m 0.4 m a v e r a g e s ) .  o f t h e rms g r a d i e n t show t h a t m o s t o f t h e v a r i -  a n c e a r i s e s f r o m a f e w p a t c h e s w i t h a t h i c k n e s s o f one t o t h r e e m e t r e s and w i t h i n t e n s i t i e s  o f \ t o \\ C°/m ( r m s , u n c o r r e c t e d f o r t h e f r e -  quency response o f t h e p r o b e s ) .  A l a r g e p a t c h found  i n one p r o f i l e  may c o r r e s p o n d t o no p a t c h a t a l l i n t h e o t h e r p r o f i l e i n s t a n c e n e a r 105 m).  A s i n t h e November 1973 d r o p s , r e g i o n s o f t h e  p r o f i l e s w h e r e t h e t e m p e r a t u r e i s u n i f o r m show l i t t l e in  the rest of the p r o f i l e s ,  the  t h e r e i s no c l e a r r e l a t i o n s h i p  including  mean s q u a r e g r a d i e n t a v e r a g e d t h e upper  aged o v e r b o t h p r o f i l e s  over the whole  20 m) a n d t h e n e t t e m p e r a t u r e  found a c r o s s i t a r e g i v e n i n Table I I I .  between  F i g u r e 29 shows c l e a r l y  that  this  profile  difference  The mean s q u a r e g r a d i e n t a v e r -  i s 26.5 x 10 ^ (C°/m)^.  g r a d i e n t v a l u e o f p r o f i l e A i s about B.  rms g r a d i e n t a n d ,  v a l u e o f t h e rms g r a d i e n t a n d t h a t o f t h e l o c a l mean g r a d i e n t .  The (not  (see f o r  The mean  square  t w i c e as l a r g e as t h a t o f p r o f i l e i s due t o t h e o c c u r r e n c e o f  d i f f e r e n t rms g r a d i e n t p a t c h e s i n e a c h p r o f i l e .  I n each p r o f i l e , t h r e e  o r f o u r p a t c h e s c a n a c c o u n t f o r more t h a n 9 0 % o f t h e g r a d i e n t  c)  variance.  Temperature s t r u c t u r e i n t h e Inner B a s i n ' s I n t e r m e d i a t e Water:  On F e b r u a r y 6, 1 9 7 4 , f o u r d o u b l e P u m p k i n d r o p s a n d a number o f STD p r o f i l e s w e r e made i n t h e I n n e r B a s i n o f Howe S o u n d . the p a r t of the p r o f i l e s which  comes f r o m t h e I n t e r m e d i a t e W a t e r  100 m, s e e c h a p t e r I I ) i s e x a m i n e d . section d).  Here,  only  (10 t o  T h e Deep W a t e r i s r e s e r v e d f o r  D r o p s 7 t o 10 a r e shown i n f i g .  t i o n i n Howe Sound i s shown i n f i g . 2 8 .  30 t o 33 a n d t h e i r  loca-  One l o n g - c h a n n e l STD s e c t i o n  and o n e c r o s s - c h a n n e l STD s e c t i o n a r e p r e s e n t e d i n f i g . 3 9 a n d 4 0 .  All  the temperature p r o f i l e s  (STD a n d P u m p k i n s ) d i f f e r  e a c h o t h e r m o s t l y i n t h e 30 t o 70 m r a n g e . ing to their  from  They c a n be grouped a c c o r d -  resemblance.  - D r o p 7 ( f i g . 3 0 ) a n d STD #7 ( f i g . 4 0 ) show a l a y e r o f r e l a t i v e l y u n i f o r m t e m p e r a t u r e b o u n d e d b y two s h a r p t e m p e r a t u r e s t e p s . fig.30,  t h i s l a y e r has been l a b e l l e d  " l a y e r B".  In  STD $7 was o b t a i n e d  n e a r t h e S-E s i d e o f t h e c h a n n e l a t Howe 4 w h i l e D r o p 7 was a l s o o b t a i n e d a t Howe 4.  - D r o p s 8 a n d 9 ( f i g . 3 1 a n d 32) a n d STD #6 a n d #8 ( f i g . 3 9 a n d 40) h a v e a p r o f i l e w h e r e  t h e " l a y e r B" d o e s n o t show c l e a r l y .  wise they a r e very s i m i l a r  to the p r o f i l e s  o f Drop  Other-  7 a n d STD #7.  They  w e r e o b t a i n e d a t Howe 4, n e a r t h e c e n t e r o f t h e c h a n n e l .  - D r o p 10 ( f i g . 3 3 ) a n d STD #5, #9, a n d #10 ( f i g . 3 9 a n d 40) h a v e i n common a t e m p e r a t u r e " b u l g e " l a b e l l e d  o n D r o p 10 a s " l a y e r  D".  The h i g h e r r e s o l u t i o n of the Pumpkins shows t h a t the "bulge" c o n s i s t s of a temperature maximum f o l l o w e d about 10 m deeper by a minimum (Drop 10);  these seem to be made of a number of s t e p s a few metres  That  type of s t r u c t u r e was  the N-W  s i d e of the  The  rms  found  a t Howe 4.7, Howe 4.5 and Howe 4 on  channel.  g r a d i e n t p r o f i l e s of Drops 7 to 10 (Inner B a s i n  Intermediate Water) share many f e a t u r e s w i t h those of Drop 6 Basin).  Most of the g r a d i e n t v a r i a n c e i s c o n c e n t r a t e d  patches. uniform  Maximum rms  g r a d i e n t v a l u e s a r e 5 to 1 C°/m.  temperature show l i t t l e  rms  gradient.  s e v e r a l s t r i k i n g d i f f e r e n c e s between the rms Inner B a s i n and  -The  thick.  (Outer  in several Regions of  However, t h e r e are a l s o g r a d i e n t p r o f i l e s of  the  the Outer B a s i n .  rms  g r a d i e n t patches  are t h i n n e r and  fewer i n Drops 7  to 9 than i n Drop 6. -The  major rms  g r a d i e n t patches  are c l o s e l y a s s o c i a t e d  w i t h the major temperature s t e p s (mostly i n Drops 7 and 8 ) . -Rms  g r a d i e n t patches  u s u a l l y correspond well.  to patches  found  i n one  p r o f i l e of a p a i r  do  i n the o t h e r p r o f i l e of the p a i r  as  T h i s i s t r u e even f o r minor patches -The  i n Drops 7 to 9.  temperature p r o f i l e s of Drops 7 to 9 c o n t a i n s m a l l e r  and perhaps fewer temperature i n v e r s i o n s (with r e s p e c t to the main trend) than Drop  6.  T a b l e I I I p r e s e n t s the temperature d i f f e r e n c e and square  g r a d i e n t c a l c u l a t e d i n the Intermediate Water of each  the mean drop.  The  average  calculated  f r o m D r o p s 7 t o 10 i s 8.6 x 10  h i g h e s t v a l u e and t h e second drop  (Drop  8).  (C°/m) .  l o w e s t o n e a r e f o u n d i n t h e same  The  double  The v a l u e s f o u n d i n t h e I n n e r B a s i n a r e t h u s 2 t o 4  t i m e s s m a l l e r t h a n t h o s e f o u n d i n t h e O u t e r B a s i n ( n o c o r r e c t i o n made in  the frequency response).  I n D r o p s 7, 8 a n d 9, t h e h i g h rms g r a d i e n t v a l u e s seem t o be  closely related  t o the temperature  g r a d i e n t patches appear about  to extend l a t e r a l l y  20 m s i n c e t h e y a r e u s u a l l y  the temperature  steps (fine structure).  steps themselves.  p i c t u r e i s more c o n f u s e d b e c a u s e  The rms  over d i s t a n c e s larger  found on b o t h p r o f i l e s , j u s t  than  like  I n D r o p 1 0 , f u r t h e r up i n l e t , t h e the temperature p r o f i l e s  ous f i n e s t r u c t u r e l a y e r s accompanied  r e v e a l numer-  by g r a d i e n t v a r i a n c e .  s u c c e s s f u l P u m p k i n d r o p was o b t a i n e d i n t h i s  type of f i n e  b u t t h e STD s e c t i o n s i n d i c a t e  s t r u c t u r e might  that such f i n e  Only  one  structure have been  found o v e r most o f t h e i n l e t .  d)  Temperature  In this i s examined.  s t r u c t u r e i n t h e I n n e r B a s i n ' s Deep W a t e r :  s e c t i o n , t h e Deep W a t e r p a r t o f t h e P u m p k i n  profiles  The Deep W a t e r , a s d e f i n e d w i t h r e s p e c t t o t h e I n t e r m e d -  i a t e Water i n chapter I I , i s found i n the Inner B a s i n below t h a t d e p t h , t h e STD p r o f i l e s s c a l e o f t h e Pumpkin  show n o f i n e  structure.  has been expanded so t h a t s m a l l  d i f f e r e n c e s become e a s i l y d e t e c t a b l e .  The  100 m.  At  temperature  temperature  F i g . 3 4 t o 37 show t h e Deep  W a t e r p a r t o f D r o p s 7 t o 10 w i t h a n e x p a n d e d s c a l e o f t e m p e r a t u r e . The  rms g r a d i e n t s c a l e i s t h e same a s p r e v i o u s l y  easier.  t o make  comparisons  I n a l l t h e P u m p k i n p r o f i l e s , a s l i g h t t e m p e r a t u r e maximum is  f o u n d n e a r 90 t o 95 m a n d a s l i g h t minimum i s f o u n d n e a r 105 t o  110 m.  Drops  8 a n d 9 s t o p n e a r 125 m.  minimum n e a r 125 m a n d a f t e r t o n i c a l l y w i t h depth u n t i l  D r o p 10 shows a t e m p e r a t u r e  t h i s , i t s t e m p e r a t u r e i n c r e a s e s mono-  t h e e n d o f t h e d r o p , n e a r 170 m.  7, t h e Deep W a t e r t e m p e r a t u r e p r o f i l e i s v e r y s i m i l a r 1 0 , e x c e p t b e t w e e n 120 a n d 165 m. water w i t h  I n Drop  t o t h a t o f Drop  T h e r e , D r o p 7 shows two l a y e r s o f  t e m p e r a t u r e s 0.035 C ° w a r m e r t h a n t h o s e o f t h e w a t e r  above o r below  them a t s i m i l a r d e p t h i n D r o p 1 0 .  Such  found  layered  fine  s t r u c t u r e w h e r e t h e w a t e r p r o p e r t i e s a l t e r n a t e b e t w e e n two t y p e s i s o f t e n d e s c r i b e d as " i n t e r l e a v i n g " ,  an e x p r e s s i o n which suggests  that  t h e r e a r e two d i s t i n c t b o d i e s o f w a t e r a n d t h a t t h e i n s t r u m e n t s w e n t through t h e i r i r r e g u l a r boundary. two w a t e r  types i s n e g l i g i b l e ;  The d e n s i t y d i f f e r e n c e b e t w e e n t h e  the s a l i n i t y difference i s close to  0.006 °/oo.  In  t h e Deep W a t e r p a r t o f D r o p 7 ( f i g . 3 4 ) ,  g r a d i e n t v a l u e s a r e found only i n a s s o c i a t i o n w i t h ture.  the layered  struc-  The t h i c k n e s s e s o f t h e p a t c h e s f o u n d b y t h e two p r o b e s d i f f e r  by about  4 m.  distributed in  s i g n i f i c a n t rms  W i t h i n t h e p a t c h e s , t h e rms g r a d i e n t i s d i f f e r e n t l y  i n each p r o f i l e o f t h e p a i r .  Differences are also  t h e p r o f i l e s o f t e m p e r a t u r e a t s c a l e s o f up t o s e v e r a l  found  metres.  I n D r o p 8 ( f i g . 3 5 ) , a p a t c h o f rms g r a d i e n t 5 t o 10 m was  d e t e c t e d n e a r 100 m.  was  differently distributed.  able fine  On e a c h p r o f i l e o f t h e p a i r , The p a t c h was a c c o m p a n i e d  s t r u c t u r e feature of the temperature p r o f i l e .  thick  t h e rms g r a d i e n t b y no  remark-  At similar  d e p t h , n o n e o f t h e o t h e r P u m p k i n p r o f i l e s showed a n y s i g n i f i c a n t  gradient  variance.  D r o p s 9 a n d 10 ( f i g . 3 6 a n d 37) showed no r e m a r k a b l e rms gradient  IV.3  p a t c h e s i n t h e Deep W a t e r .  Discussion.  a)  An I n t e r m e d i a t e  Water c i r c u l a t i o n  I n November 1 9 7 3 , and  b o t t l e cast  sections  Howe 4.5, c r o s s - c h a n n e l channel ones.  pattern?  the cross-channel  a n d l o n g - c h a n n e l STD  showed t h a t b e t w e e n t h e s i l l  and s t a t i o n  t e m p e r a t u r e d i f f e r e n c e s were s i m i l a r  New W a t e r was f o u n d m o s t l y o n t h e S-E s i d e o f t h e  c h a n n e l and near t h e s i l l .  I n F e b r u a r y 1974,  i n t h e r a n g e o f 30 t o  70 m, d i f f e r e n c e s i n t h e a s p e c t o f t h e t e m p e r a t u r e p r o f i l e s ered i n a cross-channel  s e c t i o n a t Howe 4 w e r e s i m i l a r  encountered i n a long-channel s e c t i o n along  Dahl  phic  subject  was  (1977) h a s o b s e r v e d a n a l o g o u s c o n t r a s t s  i n Oslofjord.  equilibrium with  that currents within that  f o r c e and t h a t  the density  fjord  they appeared t o be i n g e o s t r o -  field.  Buckley  (1977) a l s o  mentioned  f o r c e w o u l d e x p l a i n why t h e New W a t e r o f November 1 9 7 3  f o u n d m o s t l y o n t h e S-E s i d e o f t h e c h a n n e l s i n c e  " r i g h t hand s i d e " f o r w a t e r e n t e r i n g Basin.  t o those of the i n l e t .  to Coriolis  that C o r i o l i s  encount-  the center  He i n t e r p r e t e d them a s a n i n d i c a t i o n are  to long-  the Inner Basin  I n F e b r u a r y 1974, t h e c r o s s - c h a n n e l  4 may b e i n t e r p r e t e d i n t h e same f a s h i o n  this  i s the  from the Outer  d i f f e r e n c e s f o u n d a t Howe  (fig.40).  These  interpretations pattern exist sill  suggest  t h a t a mean c o u n t e r - c l o c k w i s e  circulation  i n t h e I n t e r m e d i a t e Water o f t h e Inner B a s i n between t h e  a n d Howe 4.5, a n d t h a t t h i s p a t t e r n may a c c o u n t  oceanographic  p r o p e r t i e s w h i c h w e r e shown t o o c c u r  f o r changes i n  on t i m e  scales  s h o r t e r t h a n one month ( c h a p t e r I I ) .  b)  The O s b o r n - C o x m o d e l : - O u t l i n e o f t h e Osborn-Cox model:  The  f i r s t e f f o r t f o rp u t t i n g temperature  f o r m a t i o n t o use i n an oceanographic (1972). given.  In this  m o d e l i s due t o O s b o r n and Cox  section, a very b r i e f  account  o f t h i s model w i l l be  I t a p p l i e s t o r e g i o n s o f a w a t e r column where a steady  g r a d i e n t i s found; of t h e February  The Cox  microstructure i n -  (1972).  F o u r i e r heat  i n t h e Howe S o u n d d a t a , i t m i g h t a p p l y  1974 I n t e r m e d i a t e  Water.  The e s s e n c e o f t h e m o d e l c a n b e d e r i v e d s t a r t i n g diffusion  equation  e  f o r an i n c o m p r e s s i b l e  =  the c o e f f i c i e n t of molecular  ^v e  (iv.i)  2  that radiative  heat  transfers are negligible.  of variables:  diffusivity.  from the  fluid:  w h e r e D/Dt d e n o t e s t h e " m a t e r i a l d e r i v a t i v e " o p e r a t o r a n d  expansion  to regions  complete d e r i v a t i o n o f t h e model i s g i v e n i n Osborn and  ^  presents  mean  re-  I t i s assumed  N e x t , one uses t h e R e y n o l d s  u.  —  1  u.  1  1  +  u!  u.  =  E  where space  <  scale.  multiplies of  > denotes  1  <u.> 1  (IV.2)  < 6 >  t h e a v e r a g i n g made o v e r some " s u i t a b l e "  One e x p a n d s e q u a t i o n ( I V . 1 ) w i t h t h e R e y n o l d s  i t b y Q' a n d t h e n p e r f o r m s  t h e mean f i e l d  i s assumed  the averaging.  variables,  The d i v e r g e n c e  t o be n e g l i g i b l e and t h e temperature  f l u c t u a t i o n s a r e t a k e n t o be homogeneously d i s t r i b u t e d . then  time and  Equation  (IV.1)  becomes:  9_  < e^_2  3t  2  >  =  _ <  .  .e*> • 39  K  < (V0*) >  ~.  2  n U  ;  X  (2)  e q u a t i o n ( I V . 3 ) , term  that molecular d i f f u s i o n always ance.  -  3 .  1  (1)  In  f u  (3)  (3) i s always n e g a t i v e and i n d i c a t e s  a c t s as a " s i n k " f o r temperature  vari-  Term ( 2 ) r e p r e s e n t s t h e i n t e r a c t i o n s b e t w e e n t h e v e l o c i t y  fluc-  t u a t i o n s and t h e t e m p e r a t u r e temperature v a r i a n c e .  field  and a c t s g e n e r a l l y as a " s o u r c e " o f  T h e p r o d u c t <u^9'> c o r r e s p o n d s  to a  Reynolds  f l u x of heat.  F o r t h e Osborn-Cox m o d e l , one assumes a s t e a d y s t a t e and drops  term  field  o r l a t e r a l eddy f l u x e s a r e n e g l i g i b l e , b u t t h a t v e r t i c a l  are  (1).  significant.  One t h e n a s s u m e s  t h a t l a t e r a l g r a d i e n t s o f t h e mean  E q u a t i o n (IV.3) then reduces t o :  ones  <  or,  after  w'0' >  =-X  30^  i s o l a t i n g t h e v e r t i c a l eddy  < w'0'  >  < (ve  '  )2  >  (IV.4)  flux:  =  ( V 0  '  ) 2  8 6  (  I  V  '  5  )  8Z  Equation  (IV.5) p r o v i d e s an a t t r a c t i v e  method f o r e s t i m a t i n g  v e r t i c a l heat t r a n s f e r s using temperature m i c r o s t r u c t u r e o b s e r v a t i o n s p r o v i d e d t h a t t h e r e g i o n o f t h e w a t e r column where i t i s a p p l i e d p e c t s t h e assumptions o f t h e model. a shape  similar  E q u a t i o n (IV.5) c a n a l s o be g i v e n  to that of the heat d i f f u s i o n  < » e» > w  —  res-  K«  problem:  dv.6)  ||  with:  < (V0*)  U  and:  2  >  ~  (IV.8) (3Z)  In e q u a t i o n (IV.7) ^ f u s i o n and  i s an "eddy c o e f f i c i e n t "  P» i s c a l l e d  of v e r t i c a l heat d i f -  t h e C o x Number, a n o n - d i m e n s i o n a l r a t i o  which  h a s become w i d e l y a c c e p t e d f o r d e s c r i b i n g ture m i c r o s t r u c t u r e w i t h i n a monotonic  -Cox  n u m b e r s i n t h e F e b r u a r y 1974  In  t h e F e b r u a r y 1974  the " i n t e n s i t y " of  temperature  tempera-  profile.  data:  d a t a , t h e r e a r e two r e g i o n s o f t h e w a t e r  column where t e m p e r a t u r e i n c r e a s e s m o n o t o n i c a l l y w i t h d e p t h . one  i s f o u n d b e t w e e n 20 a n d  35 m i n D r o p s  7 t o 10  (fig.29  t o 33)  it  i s l a b e l l e d on D r o p 7 a n d D r o p 10 a s " l a y e r A".  is  a l s o f o u n d i n D r o p 7 t o D r o p 10 b e t w e e n 65 a n d 95 m a n d h a s  labelled "layer  In  The  The  second  first and  region been  C".  l a y e r A,  calculations derived directly  t h a t t h e mean v e r t i c a l  f r o m t h e d a t a show  t e m p e r a t u r e g r a d i e n t i s , a b o u t 0.0135 C°/m  and -3  the  mean s q u a r e v e r t i c a l  (C°/m) . 2  temperature gradient i s at l e a s t 9 x  T h i s v a l u e does n o t t a k e i n t o account the l i m i t e d  r e s o l u t i o n o f t h e p r o b e s and i n c l u d e any  i n f o r m a t i o n about  In  spatial  t h e Cox Number p r e s e n t e d h e r e d o e s n o t t h e h o r i z o n t a l component o f t h e  ature gradient at microstructure  G> >  10  scales.  < (__£')•  2  (  8  Z  I t yields:  > *  )  (36) OZ)  temper-  50  2  l a y e r C, d e t a i l e d p r o f i l e s p r e s e n t e d i n c h a p t e r V w i l l  show t h a t  most of t h e v e r t i c a l g r a d i e n t v a r i a n c e o c c u r s a t s c a l e s w h i c h can r e s o l v e d by the Pumpkins.  Depending  on how  one  chooses  be  the averaging  39  i n t e r v a l and w h i c h p r o f i l e one u s e s ,  one o b t a i n s C o x Number  estimates  of:  4  The  to  25  q u e s t i o n a r i s e s - c a n t h e s e v a l u e s be i n t e r p r e t e d a s an  eddy c o e f f i c i e n t o f v e r t i c a l d i f f u s i o n i n Howe S o u n d ' s Water?  A number o f c o n s i d e r a t i o n s h a v e t o b e t a k e n  -It  Intermediate  into  account.  i s n o t c l e a r t h a t t h e h o r i z o n t a l terms o f heat  c a n b e n e g l e c t e d w i t h i n Howe S o u n d .  transport  S e c t i o n IV.3.a suggests t h e  opposite. -It  i s p o s s i b l e t h a t most o f t h e v e r t i c a l  i s associated with processes  going  on n e a r t h e w a l l s o f t h e i n l e t o r  i n conjunction w i t h strong weather events. Osborn-Cox model s t i l l  cases, the  processes  i s taken  into  H e r e , i t was n o t . -The  estimates  I n these  a p p l i e s on t h e c o n d i t i o n t h a t t h e temperature  gradient v a r i a n c e a s s o c i a t e d w i t h these account.  transport of heat  limited  s p a t i a l r e s o l u t i o n of t h e probes r e s u l t s i n  o f t h e v e r t i c a l g r a d i e n t v a r i a n c e which a r e t o o low by an  unknown f a c t o r .  The h o r i z o n t a l component o f t h e g r a d i e n t  variance  are n o t observed.  Layer  C ( f i g . 30 a n d 33) p r e s e n t s  that i t i s located mostly a shape r e m i n i s c e n t  b e l o w maximum s i l l  an i n t e r e s t i n g problem i n depth and i t s p r o f i l e has  of p r o f i l e s found i n heat d i f f u s i o n  problems.  One w o u l d  like  t o v e r i f y i f an eddy d i f f u s i v i t y  w i t h t h e C o x Number c o u l d b e c o m p a t i b l e w i t h  coefficient  derived  the formation of l a y e r C  by v e r t i c a l  t u r b u l e n t t r a n s p o r t o r i f h o r i z o n t a l exchanges  more l i k e l y  mechanism.  provide a  On J a n u a r y 2 4 , 1 9 7 4 , STD p r o f i l e s showed t h a t t h e w a t e r c o l u m n b e t w e e n 50 a n d 100 m was n e a r l y i s o t h e r m a l ( f i g . 3 8 ) . t h e n assume t h a t b e t w e e n 60 a n d 90 m,  t h e t e m p e r a t u r e was  u n i f o r m and e q u a l t o t h e t e m p e r a t u r e o f t h e w a t e r and  constant temperature  source.  where  ^  e  2  I n t h i s problem,  =  2 ^  90 m,  This prob-  medium i n c o n t a c t w i t h a 70% o f t h e t e m p e r a t u r e  change o c c u r s w i t h i n a d i s t a n c e H f r o m t h e s o u r c e such  H  initially  found below  t h a t i t h a s been r e d u c e d by v e r t i c a l eddy d i f f u s i o n .  lem i s s i m i l a r t o t h a t o f a s e m i - i n f i n i t e  L e t us  that:  t  (IV.9)  i s t h e eddy c o e f f i c i e n t o f v e r t i c a l h e a t d i f f u s i o n and t  is  the time elapsed since the constant temperature  to  the semi-infinite  medium.  s o u r c e was  applied  U s i n g e q u a t i o n s ( I V . 8 ) and ( I V . 7 ) , one  o b t a i n s a C o x Number o f :  §  =  H  (IV.10)  2  I n l a y e r C, t h e v a l u e o f H on F e b r u a r y 6, 1974 i s a b o u t 30 m ( s e e D r o p s 7 t o 1 0 , f i g . 34 t o 3 7 ) . since the "constant temperature 1.2 x 1 0 ^ s e c ( t w o w e e k s ) .  T h e maximum t i m e e l a p s e d  s o u r c e " c o n d i t i o n was a p p l i e d i s a b o u t  Using a molecular heat  diffusion  c o e f f i c i e n t o f 1.4  x 10  Number s h o u l d be a b o u t  -7  2 m / s e c we  2600.  find  that the v a l u e of the  Cox  T h i s v a l u e i s at l e a s t a f a c t o r of  100  l a r g e r t h a n t h e v a l u e s r e p o r t e d e a r l i e r on t h e b a s i s o f t h e P u m p k i n data.  One  c o n c l u d e s t h a t l a y e r C was  formed perhaps  through  inter-  m i t t e n t " c a t a s t r o p h i c " m i x i n g e v e n t s w h i c h w e r e n o t o b s e r v e d o r , more likely,  t h a t t h e shape o f the p r o f i l e of l a y e r C r e s u l t s from  a d v e c t i o n of w a t e r coming the  c)  f r o m t h e O u t e r B a s i n and  p r o f i l e does n o t r e s u l t  t h a t t h e shape  equation i t may  Osborn-Cox model i s a p a r t i c u l a r  (IV.3).  Here, another p a r t i c u l a r  be b e t t e r  suited  Sound's I n n e r B a s i n .  fluid:  case d e r i v e d  f o r a d e s c r i p t i o n o f t h e Deep W a t e r o f Howe  Take a volume o f f l u i d  with i t s surroundings.  whole volume, and  (water) w h i c h has  heat  dropped  i t becomes:  < B  3t  In  this  —  -  • -K  <  ( v e  '  ) 2  «v.ii)  >  2  case,  0  ( w h i c h does n o t appear  e q u a t i o n ) i s t h e mean t e m p e r a t u r e w i t h i n  temperature f i e l d  <0' > 2  and  explicitly  t h e volume and  s t a y c o n s t a n t s i n c e t h e r e a r e no h e a t e x c h a n g e s  and i t s s u r r o u n d i n g s . the  no  an  Then, i f a v e r a g i n g i s done o v e r t h e  t h e t r a n s p o r t ' t e r m s o f e q u a t i o n ( I V . 3 ) c a n be  _  to  from  case i s presented because  i n h o m o g e n e o u s t e m p e r a t u r e d i s t r i b u t i o n and w h i c h u n d e r g o e s exchanges  of  from v e r t i c a l m i x i n g .  A m o d e l f o r an i s o l a t e d and inhomogeneous v o l u m e o f  The  the  i n the  i t i s expected  between the volume  i s a measure of the inhomogeneity  of  i t i s e x p e c t e d t o d e c r e a s e w i t h t i m e due  to  the mixing can  e f f e c t of m o l e c u l a r  d e r i v e a time  diffusion.  From e q u a t i o n  (IV.11),  s c a l e which d e s c r i b e s the r a t e at which the  a t u r e d i f f e r e n c e s w i t h i n the f l u i d  are being  d i s s i p a t e d by  one  temper-  molecular  processes:  < e* 2 %  In  equation  <  2  >  (V0 ) 1  2  >  (  STD  probe.  g r a d i e n t v a r i a n c e h o w e v e r i s a more d i f f i c u l t s p a t i a l r e s o l u t i o n has occur  t o be  i n t e r m i t t e n t l y and  probes to sample (near case).  V  '  ( I V . 1 2 ) , t h e t e m p e r a t u r e v a r i a n c e i s an e a s y p a r a m e t e r  measure, u s i n g f o r example a s t a n d a r d  may  I  a t t a i n e d and  full  task since a very  high  s i n c e the g r a d i e n t  t h e b o t t o m o r t h e s i d e s o f Howe S o u n d i n  o b t a i n e d by  a t t e m p t can  still  this  t e m p e r a t u r e b e t w e e n November 1973  data.  The  significant and  the  data  t h e P u m p k i n s i n t h e Deep W a t e r o f Howe S o u n d and  Sound a p p e a r s t o h a v e u n d e r g o n e no  the  gradient.  be made t o m a t c h some o f t h e  i n f o r m a t i o n coming from oceanographic  )  variance  Moreover, f r e e - f a l l i n g m i c r o s t r u c t u r e probes measure o n l y  An  2  to  Measuring the  at l o c a t i o n s which are dangerous f o r  v e r t i c a l component of t h e t e m p e r a t u r e  1  January  other  Deep W a t e r o f Howe  c h a n g e i n i t s mean 1974.  During  that period,  b o t t l e c a s t m e a s u r e m e n t s showed t h a t t h e maximum t e m p e r a t u r e d i f f e r e n c e f o u n d w i t h i n t h e Deep W a t e r d e c r e a s e d suggests  a mixing  time  f r o m 0.5  C°  t o 0.17  C°.  s c a l e of about t h r e e months ( t a k i n g f o r  an e x p o n e n t i a l d e c a y ) and  thus:  T  ^  10^  sec  This granted  The maximum t e m p e r a t u r e d i f f e r e n c e i n F e b r u a r y 1974 was p r o b a b l y to  0.2 C° a n d t h i s  suggests  that:  < 6'  Equation  >  2  0.01 ( C ° )  2  (IV.10) t h e n r e q u i r e s t h a t on t h e a v e r a g e , t h e l e v e l o f  gradient variance  f o u n d i n t h e Deep W a t e r b e :  < (V0')  This value gradient  signal.  vable patches instruments).  2  >  ^  3 x 10"  i s c l o s e t o t h e rms n o i s e  (from  s u c h a mean v a l u e  should  3  (C°/m)  2  l e v e l o f t h e Pumpkin's  H o w e v e r , due t o t h e p a t c h i n e s s  ance d i s t r i b u t i o n ,  of the gradient  give r i s e  D r o p s 7 a n d 8 ( f i g . 3 0 a n d 3 1 , F e b r u a r y 1 9 7 4 ) show p a t c h e s  2  w i t h i n the patches.  response of the probes would i n c r e a s e  of a t  Correcting f o r the  t h i s value; averaging  Deep W a t e r w a t e r c o l u m n w o u l d r e d u c e i t a l t h o u g h  other  frequency  over the  patches  could  e l s e w h e r e w i t h i n t h e Deep W a t e r .  I n terms of o r d e r s observations in  obser-  the point of view of the s e n s i t i v i t y of the  10 t o 20 ( C ° / m )  well exist  vari-  to easily  o f a b o u t 10 m t h i c k n e s s a n d w i t h mean s q u a r e g r a d i e n t v a l u e s least  close  o f m a g n i t u d e , i t seems t h a t t h e P u m p k i n  show some c o n s i s t e n c y w i t h t h e b o t t l e c a s t t i m e s e r i e s  t h e Deep W a t e r a s i n t e r p r e t e d i n t h e l i g h t o f e q u a t i o n  (IV.12).  What i s m i s s i n g now i s a m o r e c o m p l e t e c o v e r a g e o f t h e o c c u r r e n c e temperature gradient variance w i t h i n the Inner s p a t i a l r e s o l u t i o n f o r the probes.  B a s i n and a  higher  of  Chapter V  V.l  Introduction.  T h i s chapter microstructure obtained as to p r e s e n t  presents  21 d e t a i l e d p r o f i l e s o f temperature  i n Howe Sound.  They have been s e l e c t e d so  s t r u c t u r e s which a r e t y p i c a l o f those  d i f f e r e n t r e g i o n s of the water column p r e s e n t e d IV.  found i n the  i n chapters T i l and  They a r e d i s c u s s e d i n terms of h o r i z o n t a l e x t e n t ,  relation-  s h i p between f i n e s t r u c t u r e and m i c r o s t r u c t u r e , and p o s s i b l e causes f o r t h e i r  existence.  When two probes have been used s i m u l t a n e o u s l y , i n g p r o f i l e s a r e shown s i d e by s i d e .  The u s u a l s i g n c o n v e n t i o n i s  used to l a b e l the s c a l e of the v e r t i c a l temperature  gradient  ( p o s i t i v e g r a d i e n t when temperature i n c r e a s e s upwards). however t h a t , due to an i n c o n s i s t e n c y d u r i n g the data p o s i t i v e v a l u e s a r e p l o t t e d on the l e f t are l a b e l l e d  accordingly.  the r e s u l t -  Notice  processing,  s i d e of zero g r a d i e n t and  45  V.2  Detailed  A)  profiles.  November 1 9 7 3 p r o f i l e s :  F i g u r e s 2 1 t o 24 show s e g m e n t s o f D r o p s  12 a n d 1 3 .  d r o p s w e r e made a t s t a t i o n Howe 4 o n November 2 1 , 1 9 7 3 . p r o f i l e s o f D r o p 12 a n d 13 a r e p r e s e n t e d i n f i g .  These  The o v e r a l l  16 a n d 17 a n d t h e  depths from w h i c h t h e d e t a i l e d p r o f i l e have been taken a r e i n d i c a t e d on  them.  In f i g .  21 ( f r o m D r o p P - 1 2 ) t h e t e m p e r a t u r e i n c r e a s e s down-  w a r d s i n two " s t e p s " o f a b o u t 0.1 a n d 0.15 C ° . changes  The t e m p e r a t u r e  t a k e p l a c e o v e r v e r t i c a l d i s t a n c e s o f 0.2 t o 0.4 m.  Between  t h e two s t e p s , t e m p e r a t u r e f l u c t u a t i o n s w i t h a n rms a m p l i t u d e o f a b o u t 0.01 C° o c c u r a t s c a l e s s m a l l e r t h a n 0 . 1 m . scale  temperature f l u c t u a t i o n s rather  which give r i s e  I t i s these  than the temperature  small  "steps"  to the f l u c t u a t i o n s of the temperature gradient.  The  g r a d i e n t f l u c t u a t i o n s f o r m a " p a t c h " w h i c h e x t e n d s f r o m one temperature step to the other.  Within the "patch", the gradient  r e a c h e s p e a k v a l u e s o f 2 C°/m o r m o r e .  signal  The p e a k s a r e a b o u t  equally  d i s t r i b u t e d between p o s i t i v e and n e g a t i v e v a l u e s .  In fig.22  ( a l s o f r o m Drop P-12) t h e t e m p e r a t u r e  w i t h i n c r e a s i n g depth i n an i r r e g u l a r  fashion.  d e c r e a s e , t h e r e i s a s m a l l t e m p e r a t u r e jump. the gradient variance i s associated w i t h scales smaller  than 0.1m.  decreases  A t the bottom o f t h i s As i n f i g . 2 1 , most o f  temperature f l u c t u a t i o n s a t  I n t h e upper h a l f  of fig.22,  t h e peak  v a l u e s o f t h e g r a d i e n t s i g n a l h a v e m o s t l y t h e same s i g n a s t h a t o f t h e  mean g r a d i e n t .  This  p a r t o f f i g . 22  and  i s i n c o n t r a s t w i t h what i s seen i n the through out  f i g . 21.  l o c a t e d n e a r t h e b o t t o m o f f i g . 22 little  gradient  Fig.  s m a l l t e m p e r a t u r e jump  i s associated with  comparatively  variance.  23  comes f r o m a r e g i o n o f D r o p 13 w h i c h p r e s e n t s  abrupt temperature changes (see occurs  The  lower  w i t h a 0.5  C°/m  f i g . 17).  h i g h , 0.12  N e a r 37 m,  a 0.05  m thick gradient pulse.  many  C°  N e a r 38  a t e m p e r a t u r e c h a n g e w i t h a s i m i l a r m a g n i t u d e i s a c c o m p a n i e d by c l u s t e r of g r a d i e n t smaller panied  t h a n 0.05 by  spikes peaking  m.  N e a r 38.7  a single gradient  m a 0.06  most o f the g r a d i e n t peak v a l u e s  Fig.  (averaged  24 p r e s e n t s  these  small s c a l e s , there to the main t r e n d ) .  s i g n as  t h e mean g r a d i e n t .  a b o u t 0.077 C°/m  plotted here).  over i n t e r v a l s  while  In these  o f one  r a m p s , e a c h a b o u t 1.5  a nearly isothermal  respect  with  m  C°/m  examples,  t h a t of  o r two  The  temperature  thick,  a t s c a l e s o f 0.1  separated m  thick.  m or  less.  (with  l a r g e g r a d i e n t peaks have the  mean g r a d i e n t  t h e r.m.s. g r a d i e n t  r e s p o n s e o f t h e p r o b e s ) i s a b o u t 0.2  the  metres).  a r e many t e m p e r a t u r e i n v e r s i o n s A l l the  a  i s accom-  l a y e r a l s o a b o u t 1.5  mainly  C°/m,  same  t h r o u g h t h e ramps i s  (uncorrected 2\  m,  thicknesses  temperature step  h a v e t h e same s i g n as  F l u c t u a t i o n s i n temperature occur At  C°  and  a r e g i o n o f D r o p 13 w h e r e t h e  d e c r e a s e s w i t h d e p t h i n two f r o m e a c h o t h e r by  t o 2 C°/m  s p i k e w h i c h p e a k s a t more t h a n 3  ( t h e maximum v a l u e w h i c h c o u l d b e  l o c a l mean g r a d i e n t  a t 1.5  change  times  f o r the  limited  larger.  I n summary, t h e m i c r o s t r u c t u r e p r o f i l e s o f November show t h a t t h e a b r u p t t e m p e r a t u r e c h a n g e s w h i c h w e r e s e e n i n t h e  1973 overall  profiles cases.  t a k e p l a c e o v e r v e r t i c a l d i s t a n c e s o f 0.1 The  temperature changes occur e i t h e r  as r e g i o n s of l a r g e detailed in may  temperature f l u c t u a t i o n s  p r o f i l e i s s m o o t h and a l m o s t  the temperature g r a d i e n t which be c a u s e d b y  single  m o s t l y t h e same s i g n , has peaks values. to  ("ramps").  the  The v a r i a n c e profiles  of s p i k e s which  have  where the g r a d i e n t  between p o s i t i v e  and n e g a t i v e  o f a t e m p e r a t u r e c h a n g e seems p o o r l y  related  of the g r a d i e n t v a r i a n c e t h a t goes w i t h i t , i f i t i s  at a l l .  Outer B a s i n , February  detailed  presented here.  1974.  p r o f i l e s t a k e n from Drop 6 ( F e b r u a r y  D r o p 6 was  made i n R a m i l l i e s  I t s o v e r a l l p r o f i l e i s p r e s e n t e d i n f i g . 29 detailed  and  Channel  1974)  (Outer  the l o c a t i o n  of  Basin). the  p r o f i l e s i s shown on i t .  Fig.  41 p r e s e n t s a l o c a l t e m p e r a t u r e maximum f o u n d n e a r  d e p t h o f 57 m i n D r o p 6.  A t t h e t o p o f t h e warmer l a y e r ,  t u r e c h a n g e t a k e s p l a c e t h r o u g h s t e p s o f 0.1 thick.  o r as r e g i o n s where  or patches of f l u c t u a t i o n s  The m a g n i t u d e  Three are  spikes, a clustering  i n many  as a b r u p t jumps ( " s t e p s " ) ,  i s observed i n the o v e r a l l  equally distributed  the magnitude  related  B)  about  linear  to 2 metres  S t e p s were f o u n d by b o t h p r o b e s  s t e p s d i f f e r on each p r o f i l e . translate  into  t o 0.2  C°/m,  C ° , 0.2  tempera-  t o 0.5  although the d e t a i l s of  In the gradient s i g n a l ,  s p i k e s p e a k i n g a t more t h a n 3 C°/m  a t more t h a n 4.5  the  a  m  the  the steps  ( a n d i n some c a s e s  the l i m i t of the d i g i t i z e r ) .  In the  signal,  t h e s p i k e s a r e t h i n n e r t h a n 0.05 (fig.  2 9 ) , t h e s e few  I n the o v e r a l l p r o f i l e o f Drop 6  spikes give rise  gradient "patch" of t h i s  At the bottom 60 m,  m.  t o one  r.m.s.  drop.  o f t h e warmer l a y e r  (between  d e p t h s o f 59  where temperature d e c r e a s e s downwards), the temperature  t a k e s t h e s h a p e o f a s m o o t h "ramp".  The  and  profile  gradient signal consists  " r i p p l e s " w i t h a wave l e n g t h o f a b o u t 0.05 0.2  of the l a r g e s t  m and an a m p l i t u d e o f  of about  C°/m.  I n p r o f i l e B,  on t h e r i g h t o f f i g u r e 4 1 , j u s t a b o v e  the  t e m p e r a t u r e "ramp", t h e r e i s a p a t c h o f h i g h wave number g r a d i e n t fluctuations.  The  g r a d i e n t peaks  p o s i t i v e and n e g a t i v e v a l u e s . 0.4  C°/m  ( u n c o r r e c t e d ) and  are about e q u a l l y d i s t r i b u t e d  The  r.m.s. v a l u e o f t h e g r a d i e n t i s  t h e p a t c h i s 0.75  s i g n a l i n t e g r a t e s i n t o a net temperature the patch. profile  I t i s interesting  to n o t i c e  m thick.  Yet the g r a d i e n t  c h a n g e o f o n l y 0.02 t h a t no  C° a c r o s s  such p a t c h i s found i n  A.  F i g u r e 42 shows t h e d e t a i l o f a l a r g e m i c r o s t r u c t u r e found i n Drop 6 n e a r  70 m.  t h e two p a t c h e s a r e o f f s e t temperature  I n t h e o v e r a l l p r o f i l e o f Drop 6 i n d e p t h by about  s t e p s have been r e a l i g n e d  sons.  At s c a l e s of 1 m or l e s s ,  little  resemblance  scales smaller The  between  to each o t h e r .  t h a n 0.1  3 m.  (fig.29),  I n f i g u r e 42,  i n order to f a c i l i t a t e  t h e two  patch  compari-  temperature p r o f i l e s  More temperature  the  bear  fluctuations  at  m are found i n p r o f i l e A than i n p r o f i l e  B.  amplitude of the temperature f l u c t u a t i o n s  i s comparable  temperature d i f f e r e n c e found a c r o s s the "patch".  The  to the  gradient signal  peaks a t v a l u e s l a r g e r  t h a n 3 C /m,  on b o t h s i g n s .  The p a t c h o f p r o -  f i l e A c o n t a i n s s e v e r a l t i m e s more g r a d i e n t v a r i a n c e t h a n t h a t o f profile  B.  In  f i g u r e 43, the l a s t p a i r of d e t a i l e d p r o f i l e s  t o be  p r e s e n t e d i n D r o p 6, p r o f i l e A shows a l a r g e p a t c h o f g r a d i e n t f l u c t u a t i o n s which  i s n o t f o u n d a t a l l i n p r o f i l e B.  temperature p r o f i l e s  are altogether d i f f e r e n t :  t e m p e r a t u r e maximum w h i c h  Moreover,  p r o f i l e A presents a  i s n o t f o u n d i n p r o f i l e B.  w e r e s e p a r a t e d h o r i z o n t a l l y b y 10 t o 30 m a n d p r o b e B, slightly the  slower than probe A d u r i n g t h i s  p a t c h some 40 s e c o n d s  later  The two sinking  A.  temperature  s t r u c t u r e s a,t  s c a l e s o f 2 m o r l e s s o f t e n do n o t c o r r e s p o n d o n two p r o f i l e s pair.  Here,  the d e t a i l e d p r o f i l e s  of a  p r e s e n t i n s t a n c e s where t h e type  o f m i c r o s t r u c t u r e i s t h e same o n b o t h p r o f i l e s upper  probes  drop, reached the depth of  than probe  I t was n o t e d i n C h a p t e r I V t h a t  the  ( f o r i n s t a n c e on t h e  a n d l o w e r s i d e s o f t h e t e m p e r a t u r e maximum n e a r 55 m).  In  o t h e r i n s t a n c e s , t h e r e were l a r g e d i f f e r e n c e s i n t h e t y p e o f m i c r o s t r u c t u r e a s w e l l a s i n t h e amount o f g r a d i e n t v a r i a n c e o b s e r v e d , f o r i n s t a n c e , n e a r 58 m.  N e a r 105 m,  a large patch of gradient variance  was f o u n d i n one p r o f i l e w h i l e n o n e was f o u n d i n t h e o t h e r . depth, s l i g h t types.  d i f f e r e n c e s c o u l d a l s o be found  i n the l o c a l  At water  that  50  C)  F e b r u a r y 1974,  Eleven  Intermediate  Basin).  sets of d e t a i l e d p r o f i l e s obtained  i a t e Water of the  Inner  Basin are presented  s t r u c t u r e s f o u n d i n D r o p s 7, f r o m one  Water (Inner  profile  8 and  to the next.  here.  i n the  A v a r i e t y of  9 ( s t a t i o n Howe 4)  D r o p 10 p r e s e n t s  Intermed-  c a n be  a fine  traced  structure  a m i c r o s t r u c t u r e w h i c h i s d i f f e r e n t enough from t h a t of  the  and  other  drops to deserve s p e c i a l a t t e n t i o n .  Drop  7  I n the o v e r a l l p r o f i l e l o c a t e d b e t w e e n 10  and  40 m p r e s e n t s  Y e t , when s m a l l p a t c h e s a r e pair.  F i g u r e 44  these  structures.  perature 30 m).  These a r e not  i s a l s o of i n t e r e s t  rise ature  gradient  as  increases  s m a l l as (see  0.2  and  downwards  46  i n D r o p 7 n e a r 43 and  m i n the  for instance  to the main trend)  at  I n p r o f i l e A,  there  tem-  near  of  scales  n o t i c e a b l e i n the o v e r a l l  profiles. give temper-  direction).  show two 53 m  the at  to n o t i c e t h a t the g r a d i e n t peaks which  ( i n the  45  of  gives a closer look  abrupt temperature changes  (see o v e r a l l p r o f i l e ) .  t h a t each probe sensed a d i f f e r e n t m i c r o s t r u c t u r e at the step.  variance.  to the v a r i a n c e patches are found where t h e r e are a b r u p t  Figures occur  region  t o n o t i c e t h e p r e s e n c e o f a number  temperature i n v e r s i o n s (with respect  It  the  show on e a c h p r o f i l e  s e e n on b o t h p r o f i l e s  It i s interesting  m.  little  t o 34 m and  I t shows t h a t d e t a i l s c a n be  s m a l l e r t h a n 0.5  very  found, they  comes from. 28  profile  of Drop 7 ( f i g . 30),  i s a patch  of g r a d i e n t  F i g . 45  that shows  temperature  spikes with  mostly  the s i g n as the mean g r a d i e n t . occurs it,  through o n l y two  In p r o f i l e B,  the temperature change  large gradient spikes.  J u s t a few  cm  above  however, t h e r e are g r a d i e n t f l u c t u a t i o n s about a zero mean.  4 6 m,  t h e r e i s a temperature change w i t h no  significant  Near  gradient  variance.  In f i g . 4 6 , the temperature steps of both probes are accompanied by a g r a d i e n t  s i g n a l which c o n s i s t s of s e v e r a l s p i k e s  magnitudes of more than 4 C°/m. w i t h i n 0 . 2 m.  Below 5 4 m,  monotonously downwards. No  Most of the temperature change  the temperature i n c r e a s e s i r r e g u l a r l y  The  g r a d i e n t s i g n a l p r e s e n t s no  temperature i n v e r s i o n (with r e s p e c t to the main trend)  even at the s m a l l e s t s c a l e s . i s - 0 . 0 . 4 4 C ° / m while  Between 5 5 and  5 9 m,  occurs but  l a r g e peaks. i s observed  the mean g r a d i e n t  the r.m.s. g r a d i e n t i s about 0 . 0 9 C ° / m (a f a c t o r  of t h r e e above the n o i s e  level).  F i g u r e s 4 4 , 4 5 and  4 6 are t y p i c a l of t h r e e r e g i o n s of Drop 7  which are o u t l i n e d i n the o v e r a l l p r o f i l e to f i g . 3 0 and " l a y e r A",  with  " l a y e r B" and  " l a y e r C".  called  These r e g i o n s of the water column  are examined a g a i n i n Drops 8 and 9 .  Drop 8  Two (fig. one  km  4 7 and  detailed profiles 48).  Drop 8 was  taken from Drop 8 are p r e s e n t e d  made one hour a f t e r Drop 7 and  of the p o s i t i o n of Drop 7 .  shares many f e a t u r e s w i t h  The  within  o v e r a l l p r o f i l e of Drop 8  t h a t of Drop 7 .  here  Fig. changes  47 comes f r o m 19 t o 26 m.  a r e s e e n on e a c h p r o f i l e  (near  Two  main  temperature  20 a n d  23.5  m).  Near  20 m,  small temperature i n v e r s i o n i s a l s o observed i n both p r o f i l e s . t h i s r e g i o n of the water Two  temperature steps  column,  t h e mean g r a d i e n t  a c c o u n t f o r one  B e t w e e n t h e s t e p s , t h e mean g r a d i e n t  third  a n d a number o f m i n o r  temperature steps  this  trend.  temperature step, there  pulse. below  The  A t each major pulses  still  a c c o u n t f o r much o f is a  a g r a d i e n t p u l s e , t h e r e a r e a l s o some g r a d i e n t  Fig.  The  t h a t w h i c h was  gradient  separated  A t 24  f l u c t u a t i o n s which  by a l o c a l  I t presents  t e m p e r a t u r e maximum a n d  temperature l a y e r i n g of t h i s f i g u r e i s very found i n Drop 7 a t s i m i l a r depth  two  similar  ( s e e f i g . 45 a n d  What i s m i s s i n g h e r e i s a n e a r l y i s o t h e r m a l l a y e r w h i c h , i n D r o p was  f o u n d b e t w e e n 47 a n d 52 m  ( t h e t e m p e r a t u r e minimum).  s p i k e s a r e f o u n d a s i n D r o p 7. o c c u r w i t h i n one m e t r e temperature step  steps  m i n D r o p 7.  o f p r o f i l e B ( r i g h t hand s i d e )  c a n a l s o be f o u n d i n D r o p s  steps.  Notice  46). 7,  changes  that  the  consists i n fact  Such " s p l i t t i n g "  to  Gradient  H e r e , most o f t h e t e m p e r a t u r e  i n s t e a d o f 0.2  two c l o s e l y s p a c e d b u t d i s t i n c t  m,  on b o t h t r a c e s .  48 comes f r o m b e t w e e n 50 a n d 58 m.  l a r g e t e m p e r a t u r e changes a minimum.  0.001  a c c o u n t f o r most o f the g r a d i e n t v a r i a n c e .  form a s o r t of low amplitude "patch"  C°/m.  this.  s t a y s c l o s e t o 0.005 t o  C°/m  In  i s a b o u t 0.01  t o one h a l f o f  a  of  of  temperature  6 a n d 7, i n a l e s s p r o n o u n c e d  fashion.  Drop  9.  Drop 9 was Drops  a l s o made at s t a t i o n Howe 4, i n the v i c i n i t y of  7 and 8 and one hour a f t e r Drop 8.  presented i n f i g .  32.  The o v e r a l l p r o f i l e i s  Four d e t a i l e d p r o f i l e s taken from Drop 9 are  presented here.  F i g . 49 p r e s e n t s the d e t a i l e d p r o f i l e between 28 and 35  m,  the same depth range as f i g .  44 from Drop 7.  v a r i a n c e o c c u r s between 32.5  and 34 m, w i t h i n a l o c a l temperature m i n i -  mum.  At 32.5  m,  t h e r e i s a 0.2  decreases downwards. ient pulse.  m t h i c k r e g i o n where the temperature  I t i s accompanied  by o n l y a low amplitude g r a d -  The most i n t e r e s t i n g a s p e c t of f i g .  resemblance t h a t i t p r e s e n t s to f i g . changes  A p a t c h of g r a d i e n t  49 i s the s t r i k i n g  44 of Drop 7.  Most temperature  of one f i g u r e can be p a i r e d w i t h s i m i l a r ones i n the o t h e r and  the a b s o l u t e v a l u e s of the temperatures a r e v e r y c l o s e .  This  gives  the i m p r e s s i o n t h a t the d e t a i l s of the temperature p r o f i l e s may  extend  much f a r t h e r than the s p a c i n g of the two probes i n a double p r o f i l e and much l o n g e r than s e v e r a l hours.  F i g u r e s 50 and 51 come from a r e g i o n of the water where Drops  column  7 and 8 p r e s e n t e d two l a r g e temperature changes s e p a r a t e d  by a minor maximum and minimum.  Drop 9 p r e s e n t s the same " f i n e  s t r u c t u r e " but i n a d i s t o r t e d f a s h i o n .  In f i g .  50, the upper s i d e of  the temperature maximum c o n s i s t s of a "ramp" r a t h e r than a temperature step.  The bottom of the temperature maximum i s v e r y smooth and the  c o r r e s p o n d i n g g r a d i e n t s i g n a l has a unique a s p e c t .  Most of the g r a d -  i e n t v a r i a n c e i s a s s o c i a t e d w i t h the p a t c h l o c a t e d on the ramp where  t h e mean t e m p e r a t u r e i n c r e a s e s w i t h  F i g u r e 51 p r e s e n t s consists of a mixture Notice  t h e second temperature step.  o f ramp a n d s t e p  was n o t c l e a r  are presented  profiles.  t o 72 m.  file.  the processing  of the data,  s p i k e was r e a l o r s p u r i o u s  (although  t h e two t e m p e r a t u r e  f r o m a common s o u r c e  52 p r e s e n t s  A mean g r a d i e n t  of spurious  i s found.  F i g . 52 shows t h e a s p e c t  Notice  Its effect  the pro-  of temperature  exists but very  the presence of a spurious  i n the temperature p r o f i l e  g i b l e b u t i t s e f f e c t on e s t i m a t e s been l a r g e i f i t h a d gone  signal).  p a r t o f f i g . 46 ( D r o p 7 ) . The r.m.s.  m i c r o s t r u c t u r e w h e r e a s i g n i f i c a n t mean g r a d i e n t  p o i n t n e a r 57.5 m.  steps  different  o f a b o u t 0.02 C°/m e x i s t s a c r o s s  i s a b o u t 0.05 C°/m.  gradient variance  data.  a d e t a i l e d p r o f i l e from the depth range of  I t compares t o t h e l o w e r  gradient  to a single  s i d e by s i d e , they were sensed a t s l i g h t l y  and c o u l d n o t a r i s e  Fig.  During  a t f i r s t whether t h i s  T r a c e B showed t h a t i t was r e a l  65  Here, i t  s p i k e w h i c h a c c o u n t s f o r most o f t h e g r a d i e n t v a r i a n c e o f  t h i s r e g i o n o f t h e w a t e r column.  times  on b o t h d e t a i l e d  t h a t o n t r a c e A, t h e t e m p e r a t u r e s t e p g i v e s r i s e  gradient  it  depth.  of the gradient variance  little data  i s neglicould  have  unnoticed.  D r o p 10  Figures  53 a n d 54 p r e s e n t  ( s t a t i o n Howe 4.7 i n t h e I n n e r the  t h e m i c r o s t r u c t u r e o f D r o p 10  Basin)  b e t w e e n 29 a n d 54 m.  Notice  d e p t h s c a l e h a s b e e n c o m p r e s s e d b y a f a c t o r o f two c o m p a r e d  that of previous  detailed profiles.  The p r o f i l e  that  with  o f f i g . 54 f o l l o w s  immediately by  t h a t o f f i g . 53.  The d e p t h l e v e l o f 42 m i s t h u s  a l a y e r o f maximum t e m p e r a t u r e w h i c h i s a b o u t o n e m e t r e  At like  the top of f i g . 53, there  temperature p r o f i l e  i s a very  occupied  thick.  smooth, l o g a r i t h m i c -  a b o u t 3 m t h i c k ( b e t w e e n 29 a n d 32 m).  It  i s a c c o m p a n i e d b y no s i g n i f i c a n t g r a d i e n t m i c r o s t r u c t u r e e x c e p t f o r a broad, low amplitude  "pulse".  Sound m i c r o s t r u c t u r e d a t a .  i s a unique occurrence  B e t w e e n 32 a n d 36 m, t h e r e  l a y e r w i t h a somewhat s i m i l a r microstructure.  This  i n t h e Howe  i s another  temperature p r o f i l e but a very  Here, a comparatively  different  l a r g e amount o f g r a d i e n t  a n c e o r i g i n a t e s i n f l u c t u a t i o n s a t s c a l e s s m a l l e r t h a n 0.1 m. v a r i a n c e has a d i f f e r e n t  s p a t i a l d i s t r i b u t i o n w i t h i n each  Through t h e l a y e r , t h e r e  i s a l s o a s i g n i f i c a n t mean g r a d i e n t  number o f m i n o r , h i g h wave number g r a d i e n t fig.  53 p r e s e n t  mostly  little  gradient variance  spikes.  variThis  profile. and a  Other l a y e r s i n  and t h e f l u c t u a t i o n s t a k e  t h e s i g n o f t h e l o c a l mean g r a d i e n t .  I n f i g . 54, o t h e r l a y e r s 1 t o 3 m t h i c k a r e a l s o found. o f them ( a t 45 a n d 5 1 m) a r e f a i r l y  isothermal while  sent  s i g n a l c o n s i s t s mostly  a mean g r a d i e n t .  The g r a d i e n t  w h i c h h a v e t h e s i g n o f t h e mean g r a d i e n t . spike i s considered  t o be t h e r e s u l t  of a spurious  and  data  W a t e r o f D r o p 10 t h u s  8) w h i c h a r e a c c o m p a n i e d b y " o n e s i d e d " g r a d i e n t  s m a l l e r t h a n 0.5 m i n t h e t e m p e r a t u r e p r o f i l e s  gradient  point.  (compared t o those  Most o f t h e l a y e r s a r e n o t even approximately  pre-  of spikes  N e a r 49 m, a l a r g e  The m i c r o s t r u c t u r e o f t h e I n t e r m e d i a t e c o n s i s t s o f rounded temperature steps  the others  Two  of Drops 7  fluctuations.  isothermal.  Details  are usually not  identified  i n b o t h p r o f i l e s a t once.  found i n b o t h p r o f i l e s and i t i s c l e a r l a r g e r than about profiles  20 m l a t e r a l l y .  indicate that  The l a y e r s t h e m s e l v e s a r e a l w a y s that they extend over d i s t a n c e s  A s was m e n t i o n e d  t h i s s o r t o f s t r u c t u r e c o u l d have been found i n  much o f t h e I n n e r B a s i n ' s I n t e r m e d i a t e W a t e r . o n l y one i n w h i c h  i n C h a p t e r I V , STD  H o w e v e r , D r o p 10 i s t h e  t h e p r o b e s w o r k e d b e s i d e s t h e o t h e r d r o p s made a t  s t a t i o n Howe 4 a n d i n t h e O u t e r  Basin.  Summary  I n t h e I n t e r m e d i a t e W a t e r , D r o p s 7, 8 a n d 9 p r e s e n t a s i m i l a r f i n e and m i c r o s t r u c t u r e .  Comparatively large temperature  a r e f o u n d i n a l l t h r e e p r o f i l e s b e t w e e n 45 a n d 55 m. sequence  of temperature  a r e t h e same o n e s , v a r i e s b y s e v e r a l m e t r e s . have s i m i l a r v e r t i c a l and  The v e r t i c a l  l a y e r s between these s t e p s i s s i m i l a r  three p r o f i l e s although the thickness of i n d i v i d u a l  temperature  sequences  steps  layers,  i nthe  i f they  D r o p s 7, 8 a n d 9 a l s o i n t h e 15 t o 45 m  range  s u g g e s t t h a t s t r u c t u r e s 1 t o 3 m t h i c k may r e m a i n r e c o g n i z a b l e o v e r  periods of at least  s e v e r a l h o u r s a n d o v e r d i s t a n c e s much l o n g e r t h a n  t h e n o m i n a l 20 m w h i c h  s e p a r a t e ' t h e two p r o b e s  i n any g i v e n p r o f i l e .  Most o f t h e g r a d i e n t v a r i a n c e found i n t h e I n t e r m e d i a t e Water o f t h e I n n e r B a s i n i s a s s o c i a t e d w i t h nected minor  to the large temperature  the g r a d i e n t s p i k e s con-  s t e p s f o u n d b e t w e e n 45 a n d 55 m.  patches of gradient v a r i a n c e r e s u l t  from s m a l l groups  amplitude g r a d i e n t s p i k e s which occur near the minor  Other  of low  temperature  steps.  These patches a r e u s u a l l y seen on both p r o f i l e s of a p a i r and seem to extend l a t e r a l l y f u r t h e r than the nominal 20 m probe s e p a r a t i o n . the temperature p r o f i l e s , d e t a i l s as t h i n as 0.2 m can be  In  identified  at once on both p r o f i l e s of a p a i r .  The f i n e s t r u c t u r e of Drop 10 d i f f e r s markedly from t h a t of Drops  7, 8 and 9.  I t p r e s e n t s numerous l a y e r s and s e v e r a l  maxima and minima.  temperature  Most l a y e r s a r e not i s o t h e r m a l and the temperature  steps which s e p a r a t e them are rounded compared to those of the p r e c e d i n g drops.  G r a d i e n t v a r i a n c e a r i s e s m o s t l y from "one s i d e d " g r a d i e n t  f l u c t u a t i o n s , as i n the p r e v i o u s drops.  D)  Inner B a s i n Deep Water ( F e b r u a r y 1974).  Three d e t a i l e d p r o f i l e s from the Deep Water a r e p r e s e n t e d here.  The f i r s t  two,  f i g . 55 and 56, show a m i c r o s t r u c t u r e p a t c h found  i n Drop 7 between 130 and 150 m. i n Drop 8 near 105 m. which was  The depth s c a l e of the p r o f i l e s i s the same one  used f o r Drop 10.  Through f i g .  55 and 56, the temperature p r o f i l e s of b o t h  probes p r e s e n t an "S" shape. file  The o t h e r p r o f i l e shows a p a t c h found  T h i s i s a l s o v i s i b l e i n the o v e r a l l p r o -  of Drop 7 w i t h a m a g n i f i e d temperature s c a l e  (fig.  34).  The  d e t a i l s of each p r o f i l e of the p a i r d i f f e r s i g n i f i c a n t l y at s c a l e s s m a l l e r than 3m.  For i n s t a n c e , i n p r o f i l e B the downwards temperature  i n c r e a s e takes p l a c e i n a-graded f a s h i o n over 2.5 m.  In p r o f i l e  A,  the same temperature i n c r e a s e takes p l a c e i n one s i n g l e step where the  g r a d i e n t p e a k s a t m o r e t h a n 4.5 C /m.  The g r a d i e n t v a r i a n c e  a t e d w i t h t h e s p i k e o f p r o f i l e A i s o f t h e same o r d e r the v a r i a n c e  associated with the corresponding  patch  associ-  of magnitude as i n p r o f i l e B.  Many o t h e r d i f f e r e n c e s a r e a l s o f o u n d i n t h e t h i c k n e s s o f f e a t u r e s t h a t c a n be i d e n t i f i e d  Fig. 100  on b o t h  profiles.  57 shows a m i c r o s t r u c t u r e p a t c h w h i c h i s f o u n d b e t w e e n  a n d 110 m i n D r o p 8, w i t h i n a s l i g h t  overall  p r o f i l e with a magnified  t e m p e r a t u r e minimum ( s e e t h e  t e m p e r a t u r e s c a l e o f f i g . 3 5 ) . The  t e m p e r a t u r e d i f f e r e n c e s f o u n d h e r e a r e s m a l l compared t o what h a s been found i n other comparatively variance  drops  ( a b o u t 0.01 C ° h e r e ) .  low values  (typically  The g r a d i e n t  1 C°/m).  a l s o peaks a t  Much o f t h e g r a d i e n t  i s a s s o c i a t e d w i t h s c a l e s s m a l l e r t h a n 0.05 m a n d t h e g r a d i e n t  peak v a l u e s  are distributed  about e q u a l l y between p o s i t i v e  and n e g a t i v e  values.  Except f o r a few patches, presents  very  little  t h e Deep W a t e r o f Howe S o u n d  gradient variance.  are present,  t h e two p r o b e s g i v e p r o f i l e s  s c a l e s lower  than 2 or 3m.  When t e m p e r a t u r e d i f f e r e n c e s that d i f f e r s i g n i f i c a n t l y at  I t i s interesting  t o n o t i c e t h a t between  80 a n d 110 m, t h e w a t e r c o l u m n s o f D r o p s 7 t o 10 h a v e s i m i l a r ture p r o f i l e s variance.  b u t t h a t o n l y Drop 8 p r e s e n t s  a large patch  tempera-  of gradient  V.3  a)  Discussion.  Summary o f m i c r o s t r u c t u r e d e s c r i p t i o n :  In the preceding used r e p e a t e d l y  section, several expressions  f o r d e s c r i b i n g f e a t u r e s o f t h e temperature f i n e and  microstructure.  Here,  a list  i s presented.  As seen from s c a l e s o f 1 t o 5 m , p r o f i l e s were d e s c r i b e d across  them.  have been  segments o f t h e t e m p e r a t u r e  i n t e r m s o f t h e mean t e m p e r a t u r e  gradient  H e r e , "mean" o r " l o c a l mean" i n d i c a t e s t h a t a v e r a g i n g i s  made o v e r t h a t s e g m e n t .  T h u s t h e l o c a l mean g r a d i e n t may b e  w i t h a temporary f e a t u r e o f t h e w a t e r column  associated  o r may h a v e a s i g n  diffe-  r e n t f r o m t h a t o f t h e " o v e r a l l mean g r a d i e n t " a v e r a g e d o v e r a l a r g e p o r t i o n of the water  column.  •As s e e n f r o m s c a l e s o f 0.5 t o 2 m , can be d e s c r i b e d  "Temperature  roughly  temperature  i n terms o f :  s t e p s " when a t e m p e r a t u r e c h a n g e t a k e s  v e r t i c a l distance  smaller  t h a n 0.5 m  place  over a  ( i . e . i n f i g . 45 a n d 5 4 ) .  "Temperature  r a m p s " when a t e m p e r a t u r e c h a n g e t a k e s  cal distance  o f 1 m o r more i n a g r a d u a l  "irregular  microstructure  fashion  place  over a v e r t i -  (i.e. f i g .  41).  t e m p e r a t u r e c h a n g e " when a t e m p e r a t u r e c h a n g e t a k i n g  over v e r t i c a l distances  l a r g e r than 1 m i s accompanied  temperature f l u c t u a t i o n s a t smaller  scales  by l a r g e  ( i . e . f i g . 22).  place  Much o f t h e t e m p e r a t u r e g r a d i e n t m i c r o s t r u c t u r e c a n b e described  -Spikes  i n terms o f :  and p u l s e s  as a r e seen, f o r i n s t a n c e , i n f i g . 41.  -"one  sided gradient  patch  of gradient  s i g n a l " when m i c r o s t r u c t u r e c o n s i s t s o f a  f l u c t u a t i o n s w h i c h peak m o s t l y  w i t h one s i g n a s ,  f o r i n s t a n c e , i n f i g . 24. -"symmetrical present  gradient  f l u c t u a t i o n s " when t h e g r a d i e n t  peaks t a k i n g both s i g n s w i t h about equal  instance,  V.3.b)  fluctuations  frequency  as, f o r  i n f i g . 21.  R e l a t i o n s h i p s between t e m p e r a t u r e and t e m p e r a t u r e  gradient  microstructure:  The  gradient  s i g n a l displayed i n the figures i s simply the  d e r i v a t i v e of the temperature s i g n a l . questions is  may b e a s k e d s u c h a s :  Beyond t h i s r e l a t i o n s h i p ,  what type  f o u n d t o accompany s u c h and s u c h a type  structure or fine structure?  Gargett  of gradient  microstructure  of temperature  micro-  (1976) h a s a l s o sought  such  r e l a t i o n s h i p s a n d some o f h e r c o n c l u s i o n s a r e m e n t i o n e d b e l o w . are  some o b s e r v a t i o n s  sing upwards), temperature steps  i s negative  and g r a d i e n t  (temperature  spikes are often  ( s e e f i g . 4 8 , 5 0 , 5 1 ) . When t h e l o c a l mean g r a d i e n t often l i t t l e  Here  w h i c h came f r o m e x a m i n i n g t h i s d a t a s e t .  When t h e l o c a l mean g r a d i e n t  is  other  gradient variance  compared w i t h  decreafound  i s positive,  that found i n  there  neighbouring (see  regions  f i g . 50 n e a r 46  of the w a t e r column.  The  profiles  clear preference  gradient  (see  t h i s type  change ( f i g . 21, the  with respect  ( f i g . 42,  41,  43,  45)  while  i n other  temperature gradient variance  are  t h a n c o u l d be  recorded  i t s amplitude  thus i n d i c a t e t h a t the the w i d t h  instances  the patch type  of  where  temperature constitutes  temperature  pro-  by  and  temperature steps  temperature d i f f e r e n c e alone. gradient pulses r e s o l v e and  the probes  as w e l l as with  ( s e e f i g . 45  The  the cannot There of  amplitudes and  51).  t h i n n e r i s the g r a d i e n t p u l s e ,  associated variance.  For  the  observations  s i z e of a t e m p e r a t u r e change does not  of the g r a d i e n t pulses  gradient  However, i t i s o b s e r v e d t h a t  amplitude  temperature change, the  l a r g e r are  cases,  "irregular"  s p i k e s t h i n n e r t h a n what the p r o b e s can  a given  There are  associated with  the b a s i s of the  i n s t a n c e s of wide, low  higher  23).  temperature  are o f t e n a s s o c i a t e d w i t h s i n g l e  s p i k e s o r a s m a l l g r o u p o f them.  p r e d i c t e d on  s i g n of the  56).  Temperature steps  be  fluctuation  i s found j u s t above o r u n d e r n e a t h a  t e m p e r a t u r e change t h r o u g h an  file  to the  f o r i n s t a n c e f i g . 21 and  of patch  smoother  m).  "Symmetric" patches of s m a l l s c a l e g r a d i e n t show no  look  that are associated w i t h i t .  determine  V.3.c)  L a t e r a l extent  - G i v e n two two of  probes separated the  smallest  a t once?  This  of m i c r o s t r u c t u r e  temperature p r o f i l e s obtained  simultaneously  by  what i s the  something l i k e  s t r u c t u r e s which can d i s c u s s i o n b e a r s on  t h e n w e r e d o u b l e p r o f i l e s made. probes'  lateral  i n Howe S o u n d .  10  be  o r 20 m,  i d e n t i f i e d on b o t h  t h e F e b r u a r y 1974  See  chapter  data  m of  the  Inner Basin  (February  ( f i g . 44  t o 54)  show t h a t t h e p r o f i l e s  at scales smaller  t h a n 0.1  t o 0.3  m.  since  only the  t o 0.3  m c a n be  of p a i r s w i t h enough c o n s i s t e n c y  they are p a r t of the  i s to state that  differ  i n p a i r s of p r o f i l e s .  identified  Features  on  that thinner  A n o t h e r way  (by v i s u a l e x a m i n a t i o n ) i f t h e s e  to prof-  i l e s were low-passed f i l t e r e d w i t h  a c u t - o f f a t 0.3  p a i r would look almost i d e n t i c a l .  Note however t h a t c r o s s - s p e c t r a l  a n a l y s i s might not  agree w i t h  limiting  factor i n estimating  N e a r 50 m, similarity Water of  D r o p s 7,  seems t o s t o p  the  f o r matching.  Inner Basin, F i g . 55  the  or s l i g h t l y  a  fea-  different relative  r e l a t i v e d i s p l a c e m e n t s c o u l d be  a  s p e c t r a l coherences.  8 and  9 present  at scales smaller  temperature steps  t h a n 0.5  few m i c r o s t r u c t u r e  t o 57  p r o f i l e s of  t h i s r e s u l t because i d e n t i f i a b l e  t u r e s o f t e n have d i f f e r e n t t h i c k n e s s p o s i t i o n i n the water column;  m,  mostly  tempera-  t o c o n v i n c e one  same w a t e r " l e n s e s " o r l a y e r s .  m definitely differ  1974),  In other words, minor  t u r e m a x i m a o r m i n i m a t h i c k e r t h a n 0.1  look at t h i s  profiles  I I I f o r d i s c u s s i o n of  detailed profiles  t h a n 0.1  size  separation.  I n t h e u p p e r 100  both p r o f i l e s  by  m.  In the  where Deep  features are a v a i l a b l e  show t h a t s c a l e s s m a l l e r  than 1 to 3 m  are u s u a l l y d i f f e r e n t  i n two p r o f i l e s o f a p a i r .  Throughout t h e  O u t e r B a s i n ' s D r o p 6, s i m i l a r i t y b e t w e e n t h e p r o f i l e s s c a l e s s m a l l e r t h a n 1 o r 2 m i n most c a s e s  (fig.  i s small at  41 t o 4 3 ) .  - G i v e n a t e m p e r a t u r e change w h i c h i s sampled  b y two n e i g h -  b o u r i n g p r o b e s , i s t h e same tijpz. o f m i c r o s t r u c t u r e o b s e r v e d b y b o t h ?  T h r o u g h o u t t h e Howe Sound o b s e r v a t i o n s , when o n e t e m p e r a t u r e p r o f i l e was s t e p p y , t h e o t h e r o n e u s u a l l y was a l s o .  When o n e p r o f i l e  p r e s e n t e d h i g h a m p l i t u d e g r a d i e n t s p i k e s , so d i d t h e o t h e r one. a p p l i e s a l s o f o r t e m p e r a t u r e "ramps".  This  H o w e v e r , when a p a t c h o f  "symmetrical g r a d i e n t f l u c t u a t i o n s " w i t h g r a d i e n t v a r i a n c e concentrated at scales smaller other p r o f i l e  t h a n 0.05 m was f o u n d i n o n e p r o f i l e , t h e  seldom p r e s e n t e d a p a t c h w i t h s i m i l a r  examples o f t h i s were found i n Drop 6 ( f i g . (fig.  41 t o 4 3 ) .  Many  I n Drop 8  5 7 ) , a 10 m t h i c k p a t c h o f g r a d i e n t v a r i a n c e i s f o u n d b y b o t h  probes b u t the g r a d i e n t v a r i a n c e i s d i s t r i b u t e d each  extent.  differently  within  profile.  These o b s e r v a t i o n s i n d i c a t e t h a t p a t c h e s o f temperature m i c r o s t r u c t u r e o f t h e " s y m m e t r i c a l " , s m a l l s c a l e t y p e do n o t e x t e n d laterally  o v e r d i s t a n c e s a s l a r g e a s 20 m i n t h e O u t e r B a s i n ( a n d s e l -  dom o c c u r i n t h e I n n e r B a s i n i n F e b r u a r y 1 9 7 4 ) . types o f m i c r o s t r u c t u r e appear l a r g e r t h a n t h e 20 o r s o m e t r e s probes.  Other  t o extend l a t e r a l l y which  identified  over d i s t a n c e s  separated the f r e e - f a l l i n g  V.3.d)  Turbulent  o r not?  There a r e patches o f temperature m i c r o s t r u c t u r e  which,  intui-  t i v e l y , h a v e seemed t o b e " t u r b u l e n t " t o p e o p l e who h a v e s t u d i e d t h e detailed profiles.  The one m e t r e t h i c k p a t c h  a t 58 m i s o n e e x a m p l e o f t h i s .  f o u n d i n D r o p 6 ( f i g . 41)  There a r e a l s o other  water column w h i c h , i n t u i t i v e l y s t i l l ,  regions  of the  seem n o t t o b e t u r b u l e n t .  The  l o w e r s i d e o f a t e m p e r a t u r e maximum f o u n d i n D r o p 9 ( f i g . 52) i s o n e such example.  Y e t , between extreme cases l i e s t h e m a j o r i t y  structure features. be one  considered  misleading?  t o assess  t h e purpose of t h i s  is restricted  and  When t h i s  occurs,  density  scales at least. to present  eous p r o f i l e  alone  of a  turbulence  One t h e n e x p e c t s a n i n s t a n t a n e o u s  preference  structure described "symmetrical"  earlier  gradient  fluctu-  e x c h a n g e s o f f l u i d must t a k e  s t r a t i f i c a t i o n must be " t u r n e d  a disordered  allow  flow?  d i s c u s s i o n , t h e meaning of  vertical  of the v e r t i c a l  w h i c h show l i t t l e  turbulent  nature  "intuition"  t o random, s m a l l s c a l e , q u a s i - i s o t r o p i c v e l o c i t y  the l o c a l  ature  or should  Can t e m p e r a t u r e m i c r o s t r u c t u r e  the turbulent or non-turbulent  For  ations.  I s such an assessment v a l i d  of micro-  over" profile  place  at small o f temper-  a s p e c t a t s m a l l s c a l e s and an i n s t a n t a n gradient  should  present  fluctuations  f o r one s i g n o r t h e o t h e r . as " i r r e g u l a r  gradient"  Thus,micro-  and s m a l l  f l u c t u a t i o n s a r e t h e most c o n s i s t e n t  scale  with  stirring.  Irregular  temperature p r o f i l e s  and " s y m m e t r i c a l "  small  scale gradient  f l u c t u a t i o n s do n o t n e c e s s a r i l y mean t h a t t h e f l u i d  which i s being  sampled i s i n t u r b u l e n t m o t i o n .  One c a n t h i n k o f  counter examples.  Take t h e case o f a b r i e f  v i n g water s t r a t i f i e d  turbulent episode  i n d e n s i t y and t e m p e r a t u r e .  Once  invol-  three-  d i m e n s i o n a l t u r b u l e n c e s u b s i d e s , t h e p a r t i a l l y mixed volume o f water reorganizes i t s e l f  a c c o r d i n g t o i t s new d e n s i t y  structure.  heat and s a l t have d i f f u s e d a t d i f f e r e n t m o l e c u l a r r a t e s , i n g s t a b l e water column w i l l profile with small scale tions of both signs. isotropic  p r e s e n t an " i r r e g u l a r "  Because the r e s u l t -  temperature  t e m p e r a t u r e i n v e r s i o n s and g r a d i e n t  Y e t , i t i s n o more t u r b u l e n t  fluctua-  i n the semi-  sense.  M o l e c u l a r heat d i f f u s i o n a c t s towards d i s s i p a t i n g scale temperature gradient variance..  small  The p r e s e n c e o f h i g h wave number  gradient v a r i a n c e i n m i c r o s t r u c t u r e i s thus taken to suggest r e c e n t " a c t i v i t y " has t a k e n p l a c e o r i s g o i n g on. shown t h a t t e m p e r a t u r e g r a d i e n t v a r i a n c e r e s u l t s  E c k a r t (1948) h a s from the d e f o r m a t i o n  of t h e temperature f i e l d by t h e r a t e o f s t r a i n o f t h e f l u i d ' s  Due t o t h e r m a l d i f f u s i v i t y ,  an i n f i n i t e l y  sharp  s t e p w o u l d t a k e 180 s e c t o t h i c k e n t o 0.01 m i n w a t e r 1972).  Dimensional considerations involving  and  the thermal d i f f u s i v i t y  ous  temperature f i e l d ,  that  motion.  temperature  (Osborn and Cox,  a constant rate of s t r a i n  of water i n d i c a t e that,  i n an inhomogene-  temperature gradient variance a t scales of the  o r d e r o f 0.01 m c a n b e s u s t a i n e d b y a r a t e o f s t r a i n o f ( 1 8 0 s e c ) ^ o r 0.005  (m s e c "S m  sufficient  T h u s , c o m p a r a t i v e l y weak s h e a r s a r e  t o cause g r a d i e n t v a r i a n c e a t s c a l e s s m a l l e r  than those  r e s o l v e d by t h e i n s t r u m e n t s , w i t h o u t r e c o u r s e t o t u r b u l e n t p r o c e s s e s .  O s b o r n ( p e r s o n a l c o m m u n i c a t i o n ) h a s made o b s e r v a t i o n s o f b o t h t e m p e r a t u r e and v e l o c i t y m i c r o s t r u c t u r e . patches of both u s u a l l y occur together.  He h a s  found  I n s e v e r a l i n s t a n c e s , he  o b s e r v e d m i c r o s t r u c t u r e s h e a r v a r i a n c e w h e r e no o r l i t t l e g r a d i e n t v a r i a n c e was  found.  patches of v e l o c i t y  ( a n d e v e n t u a l l y t u r b u l e n t m o t i o n ) may  temperature  On  micro-  go u n d e t e c t e d  by  the b a s i s of the p r e c e d i n g d i s c u s s i o n , a t t e m p t i n g to  T u r b u l e n c e may  temperature  sensors i s r i s k y ,  go u n n o t i c e d o r e l s e m i c r o s t r u c t u r e  may  be n o n - t u r b u l e n t ( i n t h e s e m i - i s o t r o p i c s e n s e ) .  are  most c o n s i s t e n t w i t h t u r b u l e n c e a r e t h o s e w h i c h  p r o f i l e suggesting a l o c a l density overturn. i n s t a n c e , i n f i g . 41  t o 43 a n d 57.  patches  Features which present  "symmetrical" gradient fluctuations at small scales with a  for  i s homo-  s e n s o r s when t h e t e m p e r a t u r e d i s t r i b u t i o n i s h o m o g e n e o u s .  assess the occurrence of t u r b u l e n c e w i t h at best.  has  temperature  T h i s o c c u r s where temperature  g e n e o u s and b r i n g s up one m o r e p o i n t : structure  that  temperature  Such f e a t u r e s a r e  They a r e c a l l e d  found,  here  "turbulent-like".  On  the b a s i s of the preceding d i s c u s s i o n , t h e r e are  features which are c l e a r l y non-turbulent. of  the water  T h i s i s the case of r e g i o n s  column w h i c h p r e s e n t a monotonous t e m p e r a t u r e  s u c h a s f i g . 52  (Drop  t h o s e f o u n d i n f i g . 24  8 n e a r 60 m). a n d f i g . 41  i n v e r s i o n s i n t h e mean t r e n d . '  In temperature ( n e a r 59 m),  profile  "ramps" such  there are very  In view of the r e g u l a r s t r u c t u r e  s e n t e d by t h e p r o f i l e s , t u r b u l e n t s t i r r i n g explanation'(at least  also  seems t o be a n  a t t h e t i m e when t h a t f e a t u r e was  as  small pre-  unlikely  sampled).  I n Drop 6 is  associated with  thicknesses  o f one  sub-section, In the  half  variance  t o two  Water of  variance  which are not  and  ous  the  turbulent-like.  c l u s t e r s o f "one  others  are not  conclusion  f i g . 21  to 24),  Inner Basin,  can  due  be  butions  t e m p e r a t u r e and to the  possibility of the  t o 100  some f e a t u r e s  m)  most  drawn.  m.  of  features  are  t o the p a u c i t y of d a t a  and  accom-  these m.  turbulentfrom  I n t h e November 1973 found.  this  profiles The  numer-  found occur at s c a l e s of i m processes such  or  as  overturn.  not?  Doubly-diffusive convection i d e a o f i t was  preceding  f o r more t h a n a b o u t 20  o c c u r r e n c e s of a l l types are  Doubly-diffusive or  When t h e  (10  seem t o r e s u l t more f r o m a d v e c t i v e  ever s i n c e the  shown i n t h e  f o r l e s s t h a n a b o u t 20  " i n t e r l e a v i n g " r a t h e r than from t u r b u l e n t  V.3.e)  patches have  sided" gradient microstructure  but  variance  They c o n s i s t of t e m p e r a t u r e s t e p s  temperature i n v e r s i o n s which are  l a r g e r and  as  Inner Basin  p a t c h e s seem t o e x t e n d l a t e r a l l y  r e g i o n , no (see  m e t r e s and,  The  i s associated with microstructure  I n t h e Deep W a t e r o f t h e like  the gradient  a turbulent-like microstructure.  Intermediate  by  1 9 7 4 ) , most of  t h e y seem t o e x t e n d l a t e r a l l y  the gradient  panied  (Outer B a s i n ,  has  fascinated  o u t l i n e d and  salinity  density gradient  gradients  tried  oceanographers  i n laboratory  provide  opposite  tanks.  contri-  of a s t a b l e water column, t h e r e  t h a t l o c a l d e n s i t y i n s t a b i l i t i e s d e v e l o p and  l a r g e d i f f e r e n c e between the m o l e c u l a r  is a  grow b e c a u s e  d i f f u s i o n rates of  heat  and  salt.  The r e a d e r  i s r e f e r r e d t o Turner  c u s s i o n o f work c a r r i e d on t h i s  (1973) f o r a d e t a i l e d d i s -  topic before  1973 and t o M o n i n e t a l .  (1974) f o r an o v e r v i e w o f work c a r r i e d on b e f o r e 1972.  Presumption of d o u b l y - d i f f u s i v e convection u s u a l l y based on v e r t i c a l p r o f i l e s present  i n t h e ocean i s  o f temperature and s a l i n i t y  r e g u l a r l y s p a c e d l a y e r s o f homogeneous p r o p e r t i e s s e p a r a t e d  sharp property  changes o f t e n c a l l e d  to begin w i t h , the property doubly-diffusive  values  consistent  increases w i t h depth.  Since  increase w i t h depth a t l e a s t  here,  only  the temperature gradient i s  Over most o f t h e w a t e r column,  doubly-diffusive instability  temperature  t h e w a t e r column i s s t a b l e , s a l i n i t y i n a compensating f a s h i o n .  gradients are then c o n s i s t e n t w i t h  t h e development of a  of the " d i f f u s i v e type"  a r e n o t f o u n d i n t h e Howe Sound p r o f i l e s .  (see Turner,  gradient variance  Gargett  temperature gradients.  associated with negative  diffe-  with  Moreover, the  temperature gradients i s  than that associated with p o s i t i v e temperature  gradients.  (1976) a l s o o b s e r v e d t h i s r e l a t i o n s h i p between t h e i n t e n s i t y  of g r a d i e n t v a r i a n c e Cox  vertical  t o be a s s o c i a t e d  1973).  elsewhere  What i s f o u n d i s t h a t  of temperature m i c r o s t r u c t u r e tend  p o s i t i v e and n e g a t i v e  must  The o v e r a l l  However, t h e l a r g e and r e g u l a r s t e p s w h i c h h a v e b e e n o b s e r v e d  rent types  with  convection.  known w i t h some p r e c i s i o n .  property  by  i n t e r f a c e s , i n w a t e r columns where,  gradients present  In the data presented  larger  which  and t h e f i n e  (1972) a l s o o b s e r v e d  temperature l o c a l l y  s t r u c t u r e g r a d i e n t w h i l e Gregg and  the steppy  c h a r a c t e r o f m i c r o s t r u c t u r e when  i n c r e a s e s downwards.  These authors  agree  that  doubly-diffusive convection i s very l i k e l y microstructure.  to play a role  i n shaping  Gregg and Cox (1972) d i s c u s s t h i s i n more d e t a i l and  show t h a t S o r e t d i f f u s i o n  c o u l d a l s o be r e l e v a n t .  However, on t h e  b a s i s o f t h e i r d a t a and on t h e s t a t e o f knowledge, these c o u l d n o t come t o a c o n c l u s i o n a b o u t t h e i m p o r t a n c e d i f f u s i v e processes  i n oceanic environments.  authors  of doubly-  The same a p p l i e s  here.  Chapter VI  Conclusion  Howe S o u n d ' s w a t e r i s shown t o p r e s e n t The  Surface  Layer occupies  t h r e e water masses.  t h e u p p e r 10 m a n d e v o l v e s  under t h e  i n f l u e n c e o f f r e s h water r u n o f f , t i d e s and m e t e o r o l o g i c a l The  Intermediate  Strait The  Outer Basin Inner 100  Water i s c h a r a c t e r i z e d by i t s exchanges w i t h t h e  of Georgia.  Intermediate  Basin.  m.  F l u s h i n g time c a n be as s h o r t as a few weeks.  Water i s c o n s i d e r e d  t o occupy t h e whole o f t h e  ( b e l o w 10 m) a n d t h e d e p t h r a n g e o f 10 t o 100 m i n t h e T h e Deep W a t e r o c c u p i e s  I t stays trapped  for periods  t h e Inner  Howe S o u n d r e v e a l e d  types  to  c r u i s e s w h i c h w e r e made i n  9^  occurs  t u r b u l e n t - l i k e m i c r o s t r u c t u r e p a t c h e s 0.5 t o 3 m f o r l e s s t h a n 20 m.  the g r a d i e n t v a r i a n c e  Intermediate  I n t h e Inner  i nassociation t h i c k w h i c h seem B a s i n , most o f  i sassociated with microstructure features  appear t o be n o n - t u r b u l e n t Basin's  location,  I n t h e O u t e r B a s i n , most o f  temperature gradient variance  extend l a t e r a l l y  below  of microstructure which v a r i e d with  depth and temperature f i n e s t r u c t u r e .  with  Basin only,  o f months t o y e a r s .  Two t e m p e r a t u r e m i c r o s t r u c t u r e  the v e r t i c a l  effects.  a t the time of sampling.  Water, t h e l a t e r a l  extent  which  I n the Inner  of the gradient  variance  p a t c h e s a s w e l l a s t h a t o f i n d i v i d u a l f e a t u r e s a s t h i n a s 0.2 m, seems t o b e l a r g e r t h a n 20 m l a t e r a l l y .  I n t h e Deep W a t e r , f e w m i c r o s t r u c t u r e  features are detected. 2 m seem t o e x t e n d  When t h e y a r e , o n l y s c a l e s l a r g e r t h a n  f o r more t h a n a b o u t 20 m  laterally.  Regions o f t h e w a t e r column where t h e t e m p e r a t u r e ( a t s c a l e s o f 0.5 t o 2m) i s p o s i t i v e present  (temperature  gradient  decreasing  l e s s g r a d i e n t v a r i a n c e and smoother t e m p e r a t u r e  R e g i o n s where t h e t e m p e r a t u r e g r a d i e n t i s n e g a t i v e  downwards)  profiles.  often present  t e m p e r a t u r e p r o f i l e s and t h e g r a d i e n t peaks a t c o m p a r a t i v e l y T h e s e comments a p p l y  1 or  steppy  high  values.  t o m i c r o s t r u c t u r e w h i c h was n o t t u r b u l e n t - l i k e .  In  t h e November 1973 d a t a , m i c r o s t r u c t u r e p a t c h e s w h i c h c o u l d b e d e s c r i b e d as  t u r b u l e n t - l i k e occur  both  e q u a l l y w e l l w i t h i n r e g i o n s o f mean g r a d i e n t o f  signs. The  light  r o l e o f temperature m i c r o s t r u c t u r e i s examined i n t h e  o f t h e Osborn-Cox model and o f another  developed  i n this  thesis.  part of the Inner  Basin's  model f o rm i x i n g  which i s  The Oxborn-Cox model i s a p p l i e d t o t h e l o w e r Intermediate  Water.  I t suggests  that  turbulent d i f f u s i o n plays only a minor r o l e i n the Intermediate  vertical Water  n e a r 75 m, c o m p a r e d t o l a t e r a l a d v e c t i v e e x c h a n g e s b e t w e e n t h e I n n e r B a s i n and t h e o u t s i d e . important  The m i x i n g  model developed  p a r a m e t e r s t h e t e m p e r a t u r e v a r i a n c e w i t h i n t h e Deep W a t e r ,  t h e mean s q u a r e t e m p e r a t u r e g r a d i e n t , m o l e c u l a r time  scale f o r the mixing  a t h r e e month time  o f t h e Deep W a t e r .  scale f o r mixing  v a r i a n c e data a r e scant b u t they compatible scale.  here r e t a i n s as  h e a t d i f f u s i o n and a  B o t t l e cast data  t h e Deep W a t e r .  a r e o f an o r d e r  Deep W a t e r  suggested  gradient  of magnitude which i s  w i t h t h a t p r e d i c t e d by t h e model f o r t h e t h r e e month  The r e s u l t s  suggest  time  by t h e models a r e l i m i t e d by t h e a b i l i t y  of the probes t o r e s o l v e t h e f u l l  spectrum of temperature gradient  ance and by t h e p o s s i b l e i n t e r m i t t e n c y o f m i c r o s t r u c t u r e p r o d u c i n g  varievents.  References  B E L L , W i l l i a m H. 1 9 7 3 . The E x c h a n g e o f Deep W a t e r i n Howe Sound B a s i n . Pacific M a r i n e S c i e n c e D i r e c t o r a t e R e p o r t 73-13, Environment C a n a d a , V i c t o r i a , B.C.  B E L L , W i l l i a m H. 1 9 7 5 . The Howe S o u n d C u r r e n t M e t e r i n g P r o g r a m , V o l u m e I I I , P a r t I - D a t a R e p o r t , S t a t i o n HS-5. P a c i f i c M a r i n e S c i e n c e R e p o r t 75-7. I n s t i t u t e o f Ocean S c i e n c e , P a t r i c i a B a y , V i c t o r i a , B.C.  BUCKLEY, J o s e p h R. 1977. C u r r e n t s , w i n d s a n d t i d e s i n Howe S o u n d . Ph.D. T h e s i s , U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r , B.C. p p . 228.  Canadian H y d r o g r a p h i c S e r v i c e . 1977. C a n a d i a n T i d e a n d C u r r e n t T a b l e s , V o l . 5, J u a n de F u c a and S t r a i t o f G e o r g i a . C a n a d i a n H y d r o g r a p h i c S e r v i c e , Marine S c i e n c e Branch, Department o f t h e Environment, Ottawa, Canada.  DAHL, F i n n - E . 1 9 7 7 . A Note on H o r i z o n t a l G r a d i e n t s i n F j o r d s . O c e a n o g . 7_(5): 7 5 3 - 7 5 8 .  Jour. Phys.  DEFANT, A l b e r t . 1 9 6 1 . P h y s i c a l Oceanography,  DRINKWATER, K e n n e t h  Vol. I I .  Pergamon P r e s s .  F. 1 9 7 3 .  The R o l e o f T i d a l M i x i n g i n R u p e r t a n d H o l b e r g M. S c . T h e s i s , U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r , B.C. p p . 5 8 .  Inlets.  ECKART, C a r l . 1 9 4 8 . An A n a l y s i s o f t h e S t i r r i n g and M i x i n g P r o c e s s e s i n Incompressible Fluids. J o u r . Mar. Res. VII,3:265-275.  E L L I O T T , J . A . a n d N.S. OAKEY. 1 9 7 5 . H o r i z o n t a l coherence o f Temperature J o u r . P h y s . O c e a n o g . 5_: 5 0 6 - 5 1 5 .  Microstructure.  GARGETT, A n n . 1976. An I n v e s t i g a t i o n o f t h e Occurrence o f Oceanic T u r b u l e n c e w i t h r e s p e c t t o F i n e s t r u c t u r e . J o u r . Phys. Oceanog. 6:139-156.  GREGG, M.C.  a n d C.S. COX.,1972.  The V e r t i c a l M i c r o s t r u c t u r e o f T e m p e r a t u r e Deep S e a R e s . 1 9 : 3 5 5 - 3 7 6 .  GREGG, M . C ,  C.S. COX a n d P.W.  and  Salinity.  HACKER. 1 9 7 3 .  V e r t i c a l M i c r o s t r u c t u r e Measurements i n t h e C e n t r a l North P a c i f i c . J o u r . P h y s . Oceanog.' _3:458-469.  Institute  o f Oceanography o f t h e U n i v e r s i t y o f B r i t i s h  Columbia. 1973.  D a t a R e p o r t 34. B r i t i s h C o l u m b i a I n l e t s a n d P a c i f i c C r u i s e s 1972. U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r , B.C.  Institute  o f Oceanography o f t h e U n i v e r s i t y o f B r i t i s h  C o l u m b i a . 1974.  D a t a R e p o r t 35. B r i t i s h C o l u m b i a I n l e t C r u i s e s 1 9 7 3 . U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r , B.C.  Institute  o f Oceanography o f t h e U n i v e r s i t y o f B r i t i s h  Columbia. 1975.  D a t a R e p o r t 37. B r i t i s h C o l u m b i a I n l e t C r u i s e s 1 9 7 4 . U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r , B.C.  LUECK, R o l f G., Owen HERTZMAN a n d Thomas R. OSBORN. 1 9 7 7 . The S p e c t r a l R e s p o n s e o f T h e r m i s t o r s . Res. 24:951-970.  Deep S e a  MONIN, A . S . 1 9 7 7 . Variability  o f t h e Oceans. John W i l e y and Sons.  OSBORN, T.R. a n d C.S. COX. 1 9 7 2 . Oceanic Fine Structure.  G e o p h y s . F l u i d D y n . _3:321-345.  OSBORN, T.R. 1977. The D e s i g n a n d P e r f o r m a n c e o f F r e e F a l l M i c r o s t r u c t u r e Instruments a t t h e I n s t i t u t e o f Oceanography. U n p u b l i s h e d m a n u s c r i p t , I n s t i t u t e o f Oceanography, U n i v e r s i t y o f B r i t i s h C o l u m b i a , V a n c o u v e r , B.C.  P I C K A R D , G.L. 1 9 7 5 . A n n u a l a n d L o n g e r T e r m V a r i a t i o n s o f Deep W a t e r P r o p e r t i e s i n C o a s t a l Waters of Southern B r i t i s h Columbia. J o u r . F i s h . R e s . B o a r d Canada 32:1561-1587.  STOMMEL, H. a n d K.N. FEDOROV. 1 9 6 7 . S m a l l S c a l e S t r u c t u r e i n Temperature and S a l i n i t y near Timor and Mindanao. T e l l u s 19(2):306-325.  TURNER, J . S .  1973.  Buoyancy E f f e c t s i n F l u i d s . P r e s s , 367 p p .  Cambridge  University  75  Drop Number  Location  Date  (  3  R a m i l l i e s Channel  1  9  7  4  Hour  )  5 Feb.  09:25  Separation a t launch  Separation a t recovery  ±10%  ±50%  15 m  10 m  4  "  "  "  11:00  7 m  N/A  5  "  "  "  13:40  3m  20 m  6  "  "  "  14:10  20 m  N/A  6 Feb.  09:10  20 m  25 m 12 m  7  S t a t i o n Howe 4  8  "  "  "  10:10  3m  9  "  "  "  11:15  10 m  "  12:55  20 m  "  14:00  3 m  10 11  S t a t i o n Howe 4.7 "  "  Table  I  L i s t o f t h e d o u b l e d r o p s made i n t h e F e b r u a r y 1974 c r u i s e i n Howe S o u n d ' s b a s i n s , t o g e t h e r w i t h the s e p a r a t i o n o f t h e probes a t launch and a t recovery.  N/A 1 m N/A  76  Drop Number  Date  Time  Location  Mean Square Gradient 10  (1973)  3  (C°/m)  Depth Interval  2  (m)  10:25  Howe 4  11.0  38  183  P-ll  11:20  Howe 3.8  18.0  27  210  P-12  12:30  Howe 4  46.9  28  152  P-13  13:30  Howe 4  18.2  27  187  P-14  14:10  Howe 4  22.8  19  202  P-15  15:20  Howe 4  39.2  28  70  08:43  Howe 4.7  17.2  28  183  P-10  P-16  21 N o v .  22 Nov.  Table  I I  T i m e s a n d l o c a t i o n s a t w h i c h D r o p s P-10 t o P-16 w e r e made d u r i n g t h e November 1 9 7 3 c r u i s e i n Howe S o u n d . The v a l u e s o f t h e mean s q u a r e g r a d i e n t s a n d t h e d e p t h i n t e r v a l s over which  they were observed a r e a l s o g i v e n .  The mean t e m p e r a t u r e g r a d i e n t s o v e r t h e s e i n t e r v a l s was not c a l c u l a t e d because major  temperature  t h e p r o f i l e s p r e s e n t numerous  inversions.  77  D r o p Number  Intermediate Thickness  Water  (m)  Temperature Change  (C°)  Mean S q u a r e Gradient  (C°/m)  2  6-A  152  2.0  35.  6- B  162  1.8  18.  7-A  80  1.1  6.2  7- B  79  1.3  9.8  8- A  89  1.5  7.1  8- B  85  1.4  11.4  9- A  82  1.4  8.3  9-B  83  1.5  9.0  10-A  83  1.5  9.0  10-B  85  1.4  8.1  Table  III  T e m p e r a t u r e change and g r a d i e n t v a r i a n c e found i n t h e I n t e r m e d i a t e Water i n F e b r u a r y 1974.  x 10  3  78  79  Figure 2  Longitudinal section of Howe Sound and cross channel sections made at the s i l l (  ) and at Howe 4 (  ).  0  T(°C) 7 9  S(%o)  29  31  T(°C) 7 9  S(%o)  29  31  100k  200  Outer  Easin  Inner  Basin  Figure 3 Typical winter profiles of temperature and salinity in the Outer Basin and in the Inner Basin (February 1974)  CO  o  81  Temperature  O  O)  o  oo  (°C) n  o  82  Outer  Basin  Howe  2 8*3  10  U  8  cL E  6  6  30.4  _30.4 o  4- 3 0 . 0  °: 3o.o >*  4 29.6  c 29.6  29.4  SALINITY  oo 2 9 . 4  74  1973  1972 Inner Basin  Howe  4.5  10 8  J J (  6 A,SO . N D . J . F M A M . J . J A,S O . N . D . J j ^  30.4 + 30.0  oo 29.4 1973  1972 Figure 5 Comparison values in  between the temperature and s a l i n i t y average the Intermediate Water of  the Inner and Outer  Basin.  a)  u o  t9  200m  / \  a E  200m  + 8  100m  100m  TEMPERATURE  0)  -t-H——I—I—I—1—I—t  N D'J F  i  i  I  I  I  N D'J F  '  '  i  i  i  i  i  1973  1972  30.06 f  ' ' •  i  I  I  ND'J  F  I  i  i  i  1974  b)  + 30.06 200m  30.04 + ~ ,  o o o A-S-  N  "\  o o  • ••  o  o /  /  4-30.04  \  V  lOOm 30.021  4- 3 0 . 0 2  SALINITY H—h-H—I—I—I—I—I—I—IH—H N D ' J F N D ' J F 1972  Figure  - J — I — I — i — i — i — i — i — t -  1973  6  a)  and  -I—i—i—I—i-  ND'J F  b)  1974  Key t o Symbols: a 250 m A 225m __200m o 175 m O 150m • 125 m — 100m  84  CM  —h-  —  CD  a z  <  ©C5<i0  E •090 o  e  o o  e <3aQ  O  <J8i CM  > CD |<D /•O o VCJ  T3  1  0>  0)  Q Z  3 60 •H fe  /•OO / OQ  CM T3  > c o O)  u. ->  >}  Q -4-  O  O CD  O lO  O  CM  CM  CM  1- euu6!S  -4-  Q Z  01  CM ( |/|UJ)-0'Q  t-  C  SURFACE LAYER  1  |  F i gure 7 L o n g i t u d i n a l s e c t i o n o f Howe Sound showing what i s meant by Deep Water and I n t e r m e d i a t e Water.  CO  Figure 8  87  Figure 9  Figure  10  NOVEMBER  25  26  27  28 29  30  E  1  2  3  5  A  6  7  U 1  J2f."i29.^c§.iy_r?_§i1 J^-Q M J ° c)  8 • I0i J  o  31  8  9  10  11  12  13  14 15  [-9 0  O  .if  •8 r»10 • 0 -10  M re  0  -10  J  1^  n 3  Ul  n  N-S C u r r e n t at 150M (cm/sec)  H* 00 C  >-f ft)  ft  2  V  P r e d i c t i o n of Tidal E x c u r s i o n s  0  wr  N  10 J",  (M)  o N  'i  •10  0  iV  10_  Wind Record at Squamish ( M / s e c )  o  J  V  11?,  600 300-I 0  L  3  «  10  s  600 Squamish River Discharge (M7sec) -i  r~  I  -300 £ n 0  CO  ^3  COATING Figure  12  91  DROP P-16 (HOWE 4.7, EAST SIDE)  DROP P-]0 DROP P-12 DROP P-13 DROP P-14 DROP P-15 (HOWE 4)  DROP P - l l (HOWE 3.8)  .SILL  Fi gure 1 3 L o c a t i o n o f t h e temperature m i c r o s t r u c t u r e  profiles  made d u r i n g t h e November 1973 c r u i s e i n Howe Sound.  F i g u r e 14 O v e r a l l p r o f i l e o f D r o p P-10  F i g u r e ,15 O v e r a l l p r o f i l e of Drop  P-ll  94  Figure Overall profile  16  o f D r o p P-12  Figure  17  O v e r a l l p r o f i l e o f D r o p P-13  Figure  18  O v e r a l l p r o f i l e o f D r o p P-14  F i g u r e 20 Overall profile  o f D r o p P-16  i  r  r  i  +  + +  + + +  + + + + 8.4  8.6  8,8  I  L  2.0  TEMPERATUFE (°C)  0.0  Gradient (C /m) F i g u r e 21  Detailed profile  f r o m drop P-12,  •2.(  Figure Detailed profile  22 from drop  P-12.  Figure  23  Detailed profile  from drop  P-13,  102 1  1  W  1• TEMPERATURE ( C)  0  GRADIENT  F i g u r e 24 Detailed  profile  f r o m d r o p P-13.  - 1 - 2 (C°/m)  1  103  Figure 25 STD in  l o n g c h a n n e l s e c t i o n made on November Howe S o u n d ' s b o t h  basins.  13,1973  104  Figure STD  cross  26  c h a n n e l s e c t i o n made o n N o v e m b e r  a t s t a t i o n Howe 4 ( I n n e r B a s i n ) .  22,1973  Q  O O  o o  O O CM  /—\  m o  o  tu i 00  I 2  Figure STD c r o s s  channel  •>  5  s o  27  s e c t i o n made on No-vember  a t s t a t i o n Howe 4.7 ( I n n e r  Basin).  22,1973  oo vo  —'  O  106  F i g u r e 28 Location  o f the temperature  made d u r i n g t h e F e b r u a r y  microstructure  1974 c r u i s e  profiles  i n Howe S o u n d .  TEMPERATURE C O  R M S . G R A D I E N T lc°/m)  M E A N GRADIENT  (c'/m)  110  Figure  32  O v e r a l l p r o f i l e of Drop 9  Figure 33 Overall p r o f i l e of Drop 10  112 TEMPERATURE  R  #  M  -  S  >  Figure 34 Deep p a r t  o f Drop  7 with  an e x p a n d e d t e m p e r a t u r e  scale.  VERTICAL  113  R.M.S. VERTICAL GRADIENT (C°/m)  TEMPERATURE C°c) 7.5 7.7  J  7.9 !  :  8.1 i  I  I  8.3  J  1.0  !  l_  200  F i g u r e 35 Deep p a r t  o f Drop 8 w i t h  an e x p a n d e d t e m p e r a t u r e  scale.  114  Figure 36 Deep p a r t o f D r o p 9 w i t h  an e x p a n d e d t e m p e r a t u r e  scale.  115  Figure Deep p a r t  of D r o p  10 w i t h  37  an e x p a n d e d t e m p e r a t u r e  scale.  116  Temperature  ( C)  100 Depth (m)  150  J  200  250  Figure Comparison before  and d u r i n g  On t h e l e f t ,  38  between temperature  profiles  t h e F e b r u a r y 1974 m i c r o s t r u c t u r e  profiles  from the Outer  Basin:  S t a t i o n Howe 3, J a n u a r y 2 2 , 1 9 7 4 . Ramilles  t a k e n two weeks  Channel,  On t h e r i g h t , p r o f i l e s  F e b r u a r y 5, 1 9 7 4 . from t h e I n n e r  Basin:  S t a t i o n Howe 4 . 5 , J a n u a r y 2 3 , 1 9 7 4 . S t a t i o n Howe 4 . 5 , F e b r u a r y 6, 1 9 7 4 .  cruise.  F i g u r e 39 STD  l o n g c h a n n e l s e c t i o n made i n Howe S o u n d ' s I n n e r B a s i n  on F e b r u a r y  6,1974.  F i g u r e 40 STD c r o s s channel s e c t i o n made at s t a t i o n Howe 4 on F e b r u a r y 6, 1974.  119  I  C '•H  •a  l  r~v——wi„  00  Figure 41 Detailed p r o f i l e from Drop 6  in  o  Figure 42 Detailed p r o f i l e from Drop 6.  to o  121  F i g u r e 44 Detailed profile  f r o m Drop 7  123  F i g u r e 45 Detailed profile  from Drop 7  F i g u r e 46 Detailed profile  from Drop 7  125  Figure  47  Detailed profile  from Drop 8  126  F i g u r e 48 Detailed profile  f r o m Drop 8  127  128  Figure Detailed  50  profile  from Drop 9  129  Figure  51  Detailed profile  from Drop 9  130  F i g u r e 52 D e t a i l e d p r o f i l e from Drop  10  131 ^  m  o  4ruJ  L  132  F i g u r e 54 Detailed  profile  f r o m D r o p 10  133  Figure Detailed profile  55  f r o m t h e Deep W a t e r o f D r o p  7  Figure tailed  profile  56  f r o m t h e Deep W a t e r o f D r o p 7  135  .  —  E  o u  i1  -  o  Figure Detailed profile  57  f r o m t h e Deep W a t e r o f D r o p 8  

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