2A North America West Coast 



Robert L. Bernstein 



Scripps Institution of Oceanography 



University of California, San Diego 



La Jolla, California 



When coastal winds change from wintertime westerly or southwesterly 

 to summertime northerly along the North American west coast, surface 

 water is driven southward and offshore. Cooler, nutrient-rich waters 

 underneath are brought to the surface, creating conditions favorable for 

 phytoplankton growth. Thus during summer, cool, green water (high 

 chlorophyll pigment levels) is clearly detected by sensors operating in the 

 blue-green and thermal infrared portions of the spectrum. The earliest 

 seasonal development of upwelling occurs in the spring along Baja 

 California, and peaks later as one proceeds north toward Vancouver 

 Island. The process usually reaches its maximum amplitude in July along 

 the central and northern California coast. 



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