Ocean Temperatures along the West Coast of North America. 279 



Thus we would expect a concentration of the upwelling water, 

 and the correspondingly greater temperature reduction, observed. (See 

 page 264.) 



Another peculiar temperature phenomenon was observed on Aug. 

 19, 1911, in the Santa Barbara Channel between Santa Rosa Island 

 and the coast, latitude 34, longitude 120. The mean temperature of 

 the channel water was about 18, and values as high as 20,25 were 

 observed near the northern coast of Santa Cruz Island. But on ente- 

 ring Beecher's Bay on the northeast side of Santa Rosa Island a strong 

 off-shore wind was encountered, and the temperature began to fall, 

 reaching the low value of 14,8 close to shore. Now as the bay was 

 shallow about 35 meters deep on the average, the wind would tend to 

 drive the surface water in its own direction l ) (away from the shore 

 in this case) and thus cause a diminution of pressure which would 

 give rise to an upwelling of the cold bottom water. Similar pheno- 

 mena have been observed in shallow lakes (19). Thus Ek man's the- 

 ory is in harmony with shallow water circulation, as well as that in 

 the deep ocean. 



VIII. The influence of ocean temperatures on the coast climate. 



In general, the most important factor controlling climate is the 

 latitude, since it is the factor that has most to do with the geogra- 

 phical distribution of the heat received from the sun, upon which di- 

 rectly or indirectly, all meteorological processes depend. But the ac- 

 tual climate at any given place is the combined result of various 

 factors, and may be quite different from the normal for the latitude. 



On the west coast of North America the prevailing land wind 

 blows from the northwest except for a few weeks in the winter. We 

 would expect from this fact that between the ocean and the moun- 

 tains, the air temperature would be largely controlled by that of the 

 adjacent surface water of the ocean. An examination of the tempera- 

 ture diagrams for San Diego and San Francisco (Figs. 18 and 19), 

 shows a close agreement between the air and the local surface tempe- 

 ratures of the ocean, resulting in the remarkably uniform air tempe- 

 rature, entirely different from the normal for the same latitude (Figs. 1 

 and 2). 



An examination of the air isotherms (15) corresponding to the 



] ) See page 255. 



