Figure 12.-Surface salinity (%o), fall 1963. (The 183- and 1,829-m. depth contours are shown.) 



which had protruded twice as far seaward from 

 the coast of Washington during the spring was 

 absent in the fall. The 32.5%o isohaline had 

 shifted seaward from 160 km. to 400 km. by 

 fall. Although the boundary between the halo- 

 cline and lower zone fluctuated over a greater 

 depth range during the fall, the major struc- 

 tural zones were again present and continu- 

 ously defined along each section normal to 

 shore. At 200 m. the maximum salinity in- 

 creased to 33.96%o between Willapa Bay and 

 lat. 48° N. (fig. 13). The small tongue of 

 gi-eater salinity present during spring had en- 

 larged to form a continuous ridge of high 

 salinity along the coast with an axis about 140 

 km. from shore. This feature was more com- 

 plex north of lat. 48° N. where the salinity 

 decreased. 



TEMPERATURE 



In the Subarctic Pacific Region the water 

 above the halocline begins to receive a net gain 

 in heat in April and continues to warm into 

 September (Dodimead et al., 1963) . During the 

 spring the surface-temperature gradient along 

 the coast was uniform ; temperatures from 

 Vancouver Island to the Columbia River in- 

 creased from 9.0° C. to 13.5^ C. (fig. 14). 

 Off the coast of Vancouver Island the surface 

 isotherms were generally oriented northeast- 

 southwest, normal to the shore, and showed 

 no apparent relation to the surface-salinity 

 front. Off the coast of Washington, however, 

 the isotherms generally ran from north to 

 south, parallel to shore. Their configuration 

 agreed closely with the surface isohalines. 



Vertical sections of temperature during 



GEOSTROPHIC CIRCULATION 



235 



