Figure 22. — Dissolved oxygen (mg.at./l.) near the bottom at 55, 183, 914, and 1,829 m. along the 

 continental terrace, spring 1963. (The 183- and 1,829-m. depth contours are shown, and values 

 in parentheses are interpolated.) 



between the offshore water mass that intrudes 

 from the west and the coastal water mass that 

 intrudes from the south was not distinct at all 

 depths. Near 200 m. three distinct groups of 

 curves existed. Stations 11 to 13 near shore had 

 the most southern characteristics ; stations 16 

 to 19 offshore had the most northern charac- 

 teristics; and stations 14, 15, and 20 in the 

 center were intermediate between the coastal 

 and offshore water masses. Below 400 m. the 

 boundary between the coastal and offshore 

 water masses was distinct and lay between 

 stations 14 and 15, about 165 to 220 km. from 

 shore. 



The study of horizontal changes in the 

 characteristics of water masses throughout the 

 coastal area showed that the differences in 



temperature were greatest on the salinity sur- 

 face 34.0%=. Dodimead et al. (1963) sug- 

 gested that temperatures greater than 6.0' C. 

 on this surface defined the extent of the Cali- 

 fornia Undercurrent Domain which appeared 

 to originate south of lat. 35" N. Their geo- 

 strophic calculations, however, indicated only a 

 weak northward flow below 200 m. during 4 of 

 the 5 summers in 1955-59. The temperature 

 distribution on the 34.0%= salinity surface 

 during spring and fall of 1963 showed the 

 isolines were predominantly parallel to shore 

 although a tongue of warm water apparently 

 entered the area over the Continental Slope 

 from the south. The boundary between the 

 coastal and offshore water masses was marked 

 by a temperature gradient on the seaward side 



GEOSTROPHIC CIRCULATION 



245 



