118 



current conditions on the post-season cruise is referred to the 2,000- 

 decibar surface. 



In figure 45 is shown the current map resuhing from the first sur- 

 vey, March 31 to April 11. Because of the adverse conditions under 

 which they were occupied, the two northeasternmost stations of this 

 map are considered to be less reliable than usual. The rest of the 

 map, however, is considered to be of average reliability and agreed 

 in detail with the sets experienced by the surveying vessel. An 

 unusual feature is the complicated pattern introduced by the clock- 

 wise whorl centered at about 43° N., 51° W. This may possibly 

 have resulted from the March gales. Whatever the cause, the pat- 

 tern did not persist. The high velocity on the southwestern edge 

 of the Banks at about longitude 52° W., is apparently unrelated to 

 the Labrador Current moving south along the eastern edge of the 

 Banks, but perhaps is connected with the western branch of the 

 Labrador Current which, earlier in the year, brought an abnormal 

 proportion of the ice past the Avalon Peninsula. Another unusual 

 feature shown in this map is the westward fanning of the Labrador 

 Current between the forty-fourth and forty-fifth parallels. This 

 gives an indication of the source of the growlers reported in on the 

 Banks in tliis vicinity. It will be noted that this fanning occurred 

 over the shoalest part of the Banks and may have resulted from a 

 more effective stirring from the March gales here than in the deeper 

 water. It is not surprising, in view of the early date of the observa- 

 tions, that the Grand Banks whorl is conspicuous by its absence, 

 since it has been assumed in the past that tliis whorl is energized, at 

 least in part, by differential vernal warming of the waters over the 

 shoal. The margin of the Atlantic Current is seen to be flowing in 

 strength although no considerable tendency toward westward intru- 

 sion was apparent. The pools of mixed water south and southeast 

 of the Banks were larger than usual and indicated the possibility of 

 ice drifting as far west as about longitude 52° W., should any bergs 

 survive long enough to make the journey. 



Figure 46 shows the current map resulting from the data collected 

 on the second survey, April 27 to May 7. This map shows the Lab- 

 rador Current flowing in a broader than usual path and extending 

 westward of the Tail of the Banks about as far as during the first 

 survey. The Gulf Stream southwest and south of the Tail moved in 

 nearer to the Banks and decreased the size of the mixed water pooL 

 In the eastern part of the map the Atlantic Current is seen to have 

 been flowing with strength and although it is frequently characteristic 

 that as the season progresses the Atlantic Current intrudes westward 

 toward the Banks as a salient in about latitude 45° N., any advance 

 shown in figure 46 as compared with figure 45 was very slight and was 

 more in the shape of a broad front. Attention is called to the east- 



