41 



but tliis was partly compensated for by the spreading eastward of 

 the dynamic isobaths. This eastward spreading of the isobaths was 

 noted not only in the Labrador Current but also in that portion of 

 the Atlantic Current covered by the survey. This is no doubt one 

 of the effects of the previously mentioned period of strong westerly- 

 winds which existed between the two halves of the survey. Between 

 the second survey and this survey the area of cold mixed water had 

 grown some in both the southern and northeastern parts of the area 

 although this survey did not extend far enough south to determine 

 definitely the southern limits. The Atlantic Current salient had 

 gained some ground in extending northwestward toward 45°00' N., 

 47°30' W. Between the two halves of the survey the extreme limits 

 of this salient advanced somewhat in the northeastern part of the 

 area although the surface velocities were less and the highest dynamic 

 height was lower. As compared with the first two surveys, figures 

 25 and 26 show that a still larger proportion of the southward-flowing 

 current was contributed by the Grand Banks whorl rather than the 

 true Laborador Current. With regard to the changes occurring 

 between the two halves of the survey, largely the result of the period 

 of strong westerly winds during that interval, attention is called to 

 the decided stability of the current pattern, the relative permanence 

 of the position of the 971.0-meter dynamic isobath on the border of 

 the Atlantic Current, and the eastward displacement of the isobaths 

 on either side. 



Figure 27 shows the current map resulting from the fourth survey. 

 Again the similarity of the current pattern to those of the previous 

 surveys is remarkable. The Atlantic Current salient projecting north- 

 westward increased the area within its extreme limits by widening sym- 

 metrically but did not advance appreciably, and, considering surface 

 velocities, decreased in strength. The current pattern in the north- 

 eastern part of the area was moved somewhat to the northeast with- 

 out changing its general shape. The border of the Atlantic Current, 

 to be seen in the southeastern part of the map, showed little change. 

 Not much change was evident in the position or surface strength of 

 the Labrador Current although the southward-flowing cmrent 

 appeared much reduced at about latitude 44° N., because of the 

 considerable reduction in the activity of the Grand Banks whorl. 



Throughout the season the minimum observed temperatures in the 

 core of the Labrador Current were decidedly warmer than usual and 

 the Atlantic Current subnormal in both strength and temperature. 

 The season was also characterized by great stability of current pattern 

 and by the comparative absence of complicating whorls and eddies. 

 Some of the features such as the Atlantic Current salient and the cold, 

 mixed water tongue immediately northeastward of it, are identifiable 

 in each of the five current maps, and their slight changes in position 



