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The mid-depth temperature minimum in B. C. inlets

University of British Columbia

A springtime mid-depth temperature minimum has often been observed in many B.C. inlets. The size and extent of the minimum varies markedly from year to year. This paper examines the temperature minimum more closely,in Bute, Knight and Jervis Inlets. Pickard (1961) suggested that a major factor affecting the size of the temperature minimum layer might be the outflow winds which blow down most B.C. mainland fjords during winter months when the Arctic air mass moves south to cover tne interior of the province. Using Abbotsford Airport as a station representative of outflow (no wind recording devices available in Bute, Knight or Jervis) for Bute, the size of the springtime temperature minimum was compared to the outflow of the previous winter for the period 1954-1973. There seems to be a rough linear relationship between the two. During 1972, 1973 and 1974 monthly cruises were made to Jervis, Bute and Knight - (making it possible to follow winter cooling on a month to month basis. This analysis seems to indicate that in Bute, at least, most of the cooling in the winter occurs during outflow situations. The actual formation of the temperature minimum layer (as shown in the cruises of February and March) appears to be partly caused by down-inlet advection of cold water from the head. It is possible that outflow winds may cause the disturbance which is the origin of the cold advection.

Text

2010-01-21

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http://hdl.handle.net/2429/18803

Oceanography

University of British Columbia

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