THE GEOSTROPHIC CIRCULATION AND DISTRIBUTION OF WATER PROPERTIES 

 OFF THE COASTS OF VANCOUVER ISLAND AND WASHINGTON, SPRING AND FALL 



1963 



By W. James Ingraham, Jr., Oceanographer 

 Bureau of Commercial Fisheries Biological Laboratory, Seattle. Wash. 98102 



ABSTRACT 



Analysis of oceanographic data collected during the 

 spring and fall cruises of the RV George B. Kelez in 1963 

 within 220 kilometers of the coasts of Vancouver 

 Island and Washington indicated a net volume transport 

 toward the north; the flow was about 3 x 10"m.' sec. off 

 northern Vancouver Island, but only 1 x lO'm.'/sec. off 

 Washington. 



The major structural features were consistent in each of 

 the nine vertical sections of salinity, temperature, or dis- 



solved oxygen normal to shore between the Columbia 

 River and Cape Cook. 



A water mass that had higher salinity, higher tempera- 

 ture, and lower dissolved-oxygen concentration than off- 

 shore water existed over the continental slope below the 

 halocline. The implied northward flow at depth along 

 the coast was very weak. These data add to the increasing 

 body of information concerning the California Under- 

 current. 



At a conference on fishery-oceanography at 

 San Francisco, Calif., on June 2, 1947, the 

 need became obvious for repeated ocean- 

 ographic surveys along the Pacific coast up to 

 about 500 km. offshore (Sette, 1947). A gap 

 existed at the time of this conference between 

 proposed sampling off the California coast by 

 Scripps Institution of Oceanography and off 

 the Canadian coast by the Pacific Oceanogra- 

 phic Group. This gap narrowed when the De- 

 partment of Oceanography, at Oregon State 

 University, began a survey of Oregon coastal 

 waters in June 1958, and the Department of 

 Oceanography at the University of Washington 

 in January 1961 began a study of the area in- 

 fluenced by the Columbia River effluent. Ex- 

 tensive oceanographic observations from the 

 Columbia River to northern Vancouver Island 

 in the spring and fall of 1963, by the Ocean- 

 ographic Section of the Bureau of Commercial 

 Fisheries Biological Laboratory, Seattle, Wash., 

 also filled in a portion of the gap. The purpose 

 of the spring cruise was to determine ocean- 

 ographic conditions in the coastal environment 

 within 185 km. of shore (Ingraham, 1964) ; 

 the fall cruise was planned to determine wheth- 

 er significant changes had occurred since 



FISHERY BULLETIN: VOL. 66, NO. 2 



spring. The locations of oceanographic stations 

 for both cruises are shown in figure 1. 



This report presents the significant features 

 of the distributions of salinity, temperature, 

 dissolved oxygen, and water mass and the 

 circulation as shown by geostrophic currents at 

 the surface and at 200 meters. 



CIRCULATION 



Interesting aspects of the circulation close 

 to the coast are the extent, continuity, and 

 source of the surface Davidson Current and of 

 the subsurface California Undercurrent, and 

 the relationship of the two. The flow in the 

 Davidson Current has been clearly shown by 

 drift bottles released during fall, winter, and 

 early spring from as far south as central Cali- 

 fornia and recovered along the coast of British 

 Columbia. This surface current extends at least 

 93 km. from shore; it usually has an average 

 speed of about 15 cm. /sec. but speeds of about 

 40 cm. /sec. have been found (Schwartzlose, 

 1963). Burt and Wyatt (1964) reported sim- 

 ilar minimal velocities for drift bottles released 

 off Oregon during January 1961 and recovered 

 off Vancouver Island. 



223 



Published June 1967. 



