FISHERY BULLETIN: VOL. 69, NO. 2 



Figure 24. — Sea-surface temperature anomaly for No- 

 vember 1960. Hatched areas colder than normal. Heavy 

 lines represent the 1° C anomaly contours which define 

 vifarm { + ) or cold ( — ) cells. 



Figure 26. — Sea-surface temperature anomaly for June 

 1961. Hatched areas colder than normal. Heavy lines 

 represent the 1° C anomaly contours which define warm 

 ( -i- ) or cold ( — ) cells. 



Figure 25. — Sea-surface temperature anomaly for Feb- 

 ruary 1961. Hatched areas colder than normal. Heavy 

 lines represent the 1° C anomaly contours which define 

 warm (-|-) or cold ( — ) cells. 



Figure 27. — Sea-surface temperature anomaly for Oc- 

 tober 1961. Hatched areas colder than normal. Heavy 

 lines represent the 1° C anomaly contours which define 

 warm ( -|- ) or cold ( — ) cells. 



a dominant, quasi-stationary cell in a latitudinal 

 belt of either tJositive or negative anomalies, lo- 

 cated appro.ximately between lat 30° N and 

 50° N, partially encircled by anomalies of op- 

 posite sign to the north, east, and south, in a 

 zone contiguous with the North American coast. 

 The dominant cell in this model is embedded in 

 the North Pacific West Wind Drift Current. It 

 reflects a wavelike displacement of the isotherms, 

 which normally are very nearly zonal from 

 about long 150° E to 140° W in the vicinity of 

 lat 40° N. 



The fact that this cell, which defines an area 

 of maximum departure from normal in the tem- 



perature field, is not i^ropagated eastward with' 

 the ocean current suggests the existence of a 

 standing wave, or perturbation, in the current 

 structure. Assuming this to be so, water enter- 

 ing the wave would turn north (or south) of 

 its normal course, cutting across the normal iso- 

 therms and thereby causing anomalous local ad- 

 vection of high (or low) temperature. Down- 

 stream from the point of maximum excursion 

 the water cuts back toward its original course 

 and temperature conditions revert toward nor- 

 mal. Because the temperature gradient across 

 the \\'est Wind Drift Current is moderately 

 strong, a small displacement of the isotherms 



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