P aper 2 



With the continuation of the vigorous westerly regim 

 seasons over both oceans/ it is perhaps no surp 

 antecedent distribution of surface temperature anotn 

 ana ^lamias 1978) was consolidated rather than des 

 the winter of 1976. The frequent injections of arct 

 the west and central iNorth Pacific (with associated 

 cloud cover/' cold front activity/^ and surface water 

 combined with high westerly wind speeds to 

 preexisting belt of anomalously cold water across th 

 of the northern North Pacific (Fig. 2.2). In its 

 the east of Japan this cold anomaly exceeded 2F (1.1 

 south and east of this cold zone the eastern Pacifi 

 ridge extending between Hawaii and western North Ame 

 to maintain and intensify an area of abnormally 

 water centereu on 30Nr 150V/'. Core anomalies here ro 

 (0.60 from the previous season to +2. IF (+1.2C). 

 cell to the eastwards the cool conditions of antece 

 continued to preveil along the American seaboard, 

 ridge aloft extending well inlands the prime stimu 

 earlier cooling (northerly winds and coastal u 

 removed. As a result/- while still below normal/' 

 strip warmed considerably from the cold condition 

 the previous fall (Dickson and Namias 19'''8). At low 

 the North Pacific cold surface conditions extended 

 the coast once merer reflecting the northward displa 

 eastern Pacific ridge and the resulting weakness of 

 ical m id t ropos phere westerlies^ with attendant stre 

 the trade winds at surface level. 



e of previous 

 rise that the 

 aly (Dickson 

 troyed during 

 ic air over 

 c yc logenes i S/ 

 divergence) 

 maintai n the 

 e full width 



core area to 

 C). To the 

 c atmospher i c 

 rica was able 



warm surface 

 se by over 1 F 

 F lank i ng this 

 dent seasons 

 But/ with the 

 Lus for the 

 pwe lling) was 

 this coastal 

 s observed in 

 er latitudes* 

 westward from 

 cement of the 



the subtrop- 

 ngthening of 



As with the Pacific sector/ winter temperatures in the western 

 Atlantic were generally cool with an anomaly distribution similar 

 to that of the preceding fall. Building on temperatures already 

 well below normal/ centers of intense cooling developed in the 

 Newfoundland area and in the Gulf of Mexico. The former 

 reflected the arctic airflow off the winter continent and the 

 record intensity of wind speeds offshore; the severe but 

 localized cooling in the Gulf of Mexico C-4F (-2.2C) at the coreD 

 appears to be at least partly the result of periodic but intense 

 northwesterly flow from the western ridge which brought arctic 

 air and occasional record low temperatures to the Gulf coast in 

 the early part of the winter. Between these two main centers of 

 cooling/ a limited area of warm surface water was maintained off 

 the eastern seaboard where the western limb of the Atlantic 

 atmospheric ridge supported an anomalous southerly (from the 

 south) airflow. The narrow/ zonal alignment of this ridqe/ 

 however/ meant that this southerly flow and the induced warming 

 were necessarily of limited latitudinal extent. 



Many elements of the winter circulation were maintained into 

 leriQa- ^^ shown in Figure 2.3/ faster than normal mid-latitude 

 westerlies continued to prevail in both the Pacific and Atlantic 



21 



