Annual and Longer Term Variations of Deepwater Properties in the Coastal Waters of Southern British Columbia

Abstract

Observations of deepwater properties (temperature, salinity, dissolved oxygen, and the derived values of density) have been assembled from the Data Reports of the Institute of Oceanography of the University of British Columbia and values of the first three properties are presented to show the characteristics of their annual variations at 18 locations in the coastal waters of southern British Columbia. Information on the long-term variations (for 6 yr or more) of all properties is presented for eight of the locations. Variations of 1-yr period are evident to 100 m depth at all locations and to 300 m or more at many of them. The variations are of different forms, sinusoidal, peaked or saw-tooth, and there are some differences in phase between the property variations at different locations. Long-term variations (over several years) of annual mean values are small and decrease with increase of depth. Much of the evidence suggests that the changes below 100 m depth are due to longitudinal advection (flow) from elsewhere rather than to vertical transfers from the sea surface in the immediate locality.