Figures 19, 20, and 21 shown in chronological sequence the dynamic 

 topography found during the two surveys of the Grand Banks region 

 and the postseason occupation of the Bonavista triangle. In the April 

 survey, figure 19, the Labrador Current entering the northern edge of 

 the surveyed area was about normal as to speed and location. Additions 

 of water from the Grand Banks between 45° N. and 46° N. served to 

 increase the effective width of the current from 45° N. to the Tail of 

 the Banks. At the Tail of the Banks the Grand Banks water followed 

 the bottom contours to the westward but the major portion of the 

 Labrador Current continued southward beyond the 42d parallel and 

 thence curved eastward to about 48°30' W. paralleling the outer edge 

 of the Atlantic Current. At about 48°30' W. these swifter moving 

 waters curved to the southeastward beyond the limits of the survey 

 between 47° and 48° W. where a pool of colder water filled the concave 

 portion of a meander of the Atlantic Current to the right. Beyond the 

 meander the margin of the Atlantic Current pushed northward between 

 about 46° W. and 47° W. The clockwise eddy centered near 44°30' N. 

 47°00' W. contained warm water derived from this Atlantic Current 

 salient. 



It will be noted that while the dynamic heights in the low valley 

 between the Labrador Current and the Atlantic Current were about 

 normal and those on the Grand Banks were slightly above normal those 

 in the highest part of the Atlantic Current covered by the survey were 

 some 10 or 15 dynamic centimeters below normal. The Atlantic Current 

 margins in the area surveyed had a relatively thin layer of Atlantic 

 Current water under which there was a layer of anomalous mixed water 

 inclined downward to the southeast. While this anomalous mixed water 

 had a characteristic temperature salinity relationship it appeared to be a 

 mixture of the usual mixed water and Atlantic Current water. Its upper 

 surface sloped from about 300 meters at station 6369 to about 1,000 

 meters at station 6371. The under surface of this anomalous mixed 

 water was similarly inclined downward in a seaward direction over the 

 usual mixed water. In the vicinity of Flemish Cap the water was 

 Labrador Current water from its T-S characteristics, whereas usually at 

 least the southeastern part of Flemish Cap is occupied by mixed water. 

 Here, between stations 6417 to 6415, there again is indication of a 

 downward seaward inclination, this time with the usual mixed water 

 between Labrador Current water and Atlantic Current water. These 

 are considered indications that prior to this survey an unusually large 

 amount of Labrador Current water was brought into the area and that 

 vigorous wind stirring took place. Further confirmation is offered by the 

 observations which showed the characteristic temperature minimum of 

 the Labrador Current near 75 meters to have been almost completely 

 wiped out and the minimum temperatures about a half degree warmer 

 than normal. 



87 



