EBER: SEA-SURKACE TEiMPERATURE ANOMALIES 



Figure 5. — Sea-surface temperature anomaly for Oc- 

 tober 1949. Hatched areas colder than normal. Heavy 

 lines represent the 1° C anomaly contours which define 

 warm ( + ) or cold ( — ) cells. 



zone and in a southwestward tongue below 30° N 

 but with fluctuating magnitudes. 



The warm cell shrank in November and lost 

 its specific identity in December. However, the 

 general configuration of the colder than normal 

 coastal zone and warmer than normal offshore 

 region persisted through the winter and spring 

 of 1950. In May 1950, the positive anomalies 

 intensified and spread westward to Japan. The 

 pattern stabilized in June and July marked by 

 prominent warm cells in the east and far west 

 portions of the positive area (Figure 6). At 

 the same time, a cold cell in the Gulf of Alaska 

 had begun to grow and jnish southward; this 



movement continued through September (Fig- 

 ure 7) accompanied by an eastward expansion 

 of the warm belt. Ultimately, there was a de- 

 formation of the broad-scale pattei-n which had 

 for many months dominated the central and 

 eastern North Pacific, as negative anomalies 

 spread through the Gulf of Alaska. 



Figure 6. — Sea-surface temperature anomaly for July 

 1950. Hatched areas colder than normal. Heavy lines 

 represent the 1° C anomaly contours which define warm 

 ( -f ) or cold ( — ) cells. 



Figure 7. — Sea-surface temperature anomaly for Sep- 

 tember 1950. Hatched areas colder than normal. Heavy 

 lines i-epresent the 1° C anomaly contours which define 

 warm ( -f ) or cold ( — ) cells. 



The years 1951-54 presented no striking ex- 

 amples of persistent sea temperature anomalies. 

 Some relatively large-scale anomalies did devel- 

 op in this period but they were short-lived. 

 Much of the time the anomaly field was flat and 

 featureless. Midway through 1955, however, 

 a long-term progression of events began to 

 evolve with the development of an anomaly pat- 

 tern which was characterized by a positive belt 

 that stretched eastward from Japan and a neg- 

 ative zone along most of the North American 

 coast. The anomaly field intensified in August 

 (Figure 8) when maxima exceeded 2° C in the 

 warm cell and an extensive cold area was in'esent 

 in the coastal zone with negative departures 

 exceeding 1 ° C in magnitude. The negative area 

 stretched southwestward below lat 30° N. This 

 pattern prevailed through November 1955 (Fig- 

 ure 9) but became weaker in Decemljer. In 

 January 1956, the positive area contracted to 

 the west while the region of negative anomalies 

 to the east became flat and disorganized. Figure 

 10 shows the situation in February 1956. The 



347 



