25 





s«s 









3* 



4# \ 









V 









1* 



125 120 115 



ffimn 



Figure 10. — Relative frequency surfaces and frequency histograms for December. Data are shown for the 1-degree squares labelled 1 through 5 in 

 the upper left inset. Contours of relative frequency are drawn at intervals of 2.5%. Mean vector wind stress is indicated by an arrow. 



January are broad and flat and the peaks which generally 

 characterize the summer distributions are missing. Mean 

 directions shift from equatorward to poleward between 

 summer and winter. A complete reversal in the mean 

 direction occurs at point 7 (Figs. 11, 12). A shift in mag- 

 nitude is equally pronounced. Peak magnitudes are 

 higher in January than in July indicating a greater con- 

 tribution of high wind speeds in January. 



The above discussion adds a new dimension to the 

 seasonal descriptions of the surface wind stress dis- 

 tributions over the California Current. Pronounced 



seasonal variations in magnitude and direction of the 

 monthly mean wind stress are indicated along the entire 

 west coast of the United States. These changes are most 

 evident off the coasts of Oregon and Washington. In ad- 

 dition, these data suggest month to month changes in the 

 large-scale spatial variability. Frequency histograms for 

 direction and magnitude are broad and flat during the 

 winter months, and along the northern coast. Well- 

 defined peaks in magnitude and direction characterize 

 the distributions during the summer and along the 

 southern coast. 



16 



