Figure 24. — Temperature ("C.) on salinity surface 34.0%„, spring 1963. Shaded portion is above 

 6.00 c. (The 183- and 1,829-m. depth contours are shown.) 



He showed a relatively higher percentage of 

 Equatorial Pacific Water to be present along 

 the Pacific Coast near shore from lat. 25° N. 

 to lat. 45° N. All vertical sections normal to 

 shore showed a greater percentage of southern 

 water toward the bottom and toward shore. 

 The low percentages of southern water in the 

 northernmost sections (between 20 and 40 per- 

 cent) suggested increased mixing with Sub- 

 arctic Water to the north. 



The percentage of Equatorial Pacific Water 

 off the Washington coast along lat. 46°45' N. 

 during the fall of 1963 agreed closely with 

 Tibby's results (fig. 26). Because this location 

 is 222 km. farther north than Tibby's most 

 northern line, however, a slightly lower per- 

 centage was found. Percentages were not only 



relatively high near the bottom and near shore, 

 but the high percentages between 200 m. and 

 400 m. immediately below the halocline ex- 

 tended offshore as far as 500 km. This situa- 

 tion resulted in a pronounced minimum, from 

 10 to 20 percent, between 600 and 900 m. Val- 

 ues increased sharply within 220 km. of shore. 

 The depth of this minimum percentage of 

 Equatorial Pacific Water coincided surpris- 

 ingly well with the depth of the oxygen mini- 

 mum. This determination of distribution of 

 water masses suggests a change in circulation 

 with depth; between 400 m. and 1,000 m., Sub- 

 arctic Water may move onshore from the west ; 

 whereas, between 200 m. and 400 m. and be- 

 tween 1,000 m. and 1,300 m., southern water 

 may move northward along the coast. 



GEOSTROPHIC CIRCULATION 



247 



