Ocean Temperatures along the West Coast of North America. 



281 



between latitude 32 and latitude 50. Therefore, the presence of cold 

 coast water, which we have seen must be due to an upwelling from 

 the ocean depths, practically governs the coast climate. 



Since, except for a few weeks in the winter the wind blows to- 

 ward the land as well as parallel to the coast from over the ocean 

 area, and consequently passes over water areas of a successively lower 

 temperature as the coast is approached, there will be a condensation 



Pig. 21. Surface Isotherms for August. -<--- Prevailing Surface Drift. 



of the water vapor of the saturated air. Thus the formation of fogs, 

 so prevalent along the Pacific Coast may be due in part to the cold 

 water bordering the coast. If we assume the percentage of fogs for 

 any given month, that is, the average number of hours of fog per 

 hundred in that time, to be due entirely to the above cause, we would 

 expect this percentage to change in proportion to the temperature diffe- 

 rence (t). 



From the results of a large number of observations on the fre- 

 quency of fogs Me A die (20) has made a table showing the percentage 



Revne d. ges. Hydrobiol. u. Hydrogr. Bd.V. H. 2/3. 19 



