Conclusions 



A warm core eddy was found 

 between the LC and NAC east of 

 ttie Grand Banks of Newfound- 

 land. The observed flow field 

 differed substantially from that 

 suggested by the mean sea- 

 surface topography. During the 

 period of the study, a portion of 

 the Labrador Current left the slope 

 of the Grand Banks north of 45°N 

 and flowed eastward north of a 

 warm core eddy. 



The location of a portion of the 

 eddy could be mapped by SLAR. 

 The major cue was the strong 

 signal indicating higher radar 

 return from the warm water within 

 the eddy. However, not all of the 

 boundaries could be located with 

 certainty. 



The location and direction of the 

 Labrador Current in the study area 

 could be determined in some of 

 the SLAR imagery using striations 

 as flow lines. These are not 

 reliable indicators, for on most 

 days the striations were faint and 

 patchy. On one day they were 

 absent. 



In one case where IR imagery 

 could be compared to concurrently 

 collected SLAR imagery, the 

 match was excellent. The radar- 

 detected fronts were as sharply 

 defined as those in the AVHRR 

 image. 



The exact mechanism for the 

 strong radar backscatter in the 

 warm water is uncertain. It is 

 probably due to increased wind 

 stress over the warmer water. 

 Cool air blowing over much 



warmer water results in an un- 

 stable boundary layer, greater 

 wind stress, and a rougher sea 

 surface. 



The eddy was never well resolved 

 in either of the hydrographic 

 surveys: that was not the intent of 

 the study. In fact, the best evi- 

 dence for a closed circulation is 

 the subsequent anticyclonic 

 motion of the buoy left in the eddy 

 after the completion of the hydrog- 

 raphy. Exactly when the eddy 

 separated from the NAC cannot 

 be determined from the data. 

 What is clear is the effect that the 

 eddy had on the Labrador Current. 

 The distribution of the unmistak- 

 able water mass characteristics of 

 the Labrador Current and the 

 eastward motion of buoy 4542 (on 

 two separate occasions) show that 

 a portion of this current left the 

 slope of the Grand Bank at about 

 45°N. It moved eastward and 

 then northward in close proximity 

 to the eddy and finally along the 

 boundary of the NAC. 



The present study illustrates the 

 importance of research that blends 

 remote sensing with in-situ 

 sampling, with the goal of studying 

 ocean processes. Without the 

 SLAR we could not have located 

 the fronts as easily, nor recog- 

 nized the spatial and temporal 

 variability of the system. Without 

 the in-situ sampling, the imagery 

 would have been another opportu- 

 nity for unfounded speculation. 



SLAR imagery is difficult to 

 interpret but can be used with 

 other data to gain a better under- 



standing of ocean processes. In 

 addition, SLAR and SAR imagery 

 portray similar features; thus, the 

 more we learn about SLAR now, 

 the better prepared we will be to 

 interpret satellite SAR imagery 

 when it becomes available. 



The study results are important to 

 IIP for several reasons. First, they 

 provide a better recognition of the 

 role of eddies in the circulation 

 near the Grand Banks. This study 

 reports a flow pattern that differs 

 dramatically from the mean 

 Labrador Current flow that IIP 

 uses. The observed pattern 

 provides a mechanism for the 

 rapid eastward and even north- 

 ward motion of icebergs in cold 

 water (minimizing deterioration). 

 There was no apparent cross-front 

 movement. There is no confirma- 

 tion that the observed flow field 

 caused a major change in iceberg 

 distribution south of Flemish Cap. 

 Indeed, in 1986 only 204 icebergs 

 were reported south of 48°N 

 during the four-month season, 

 giving little opportunity to recog- 

 nize any iceberg distribution 

 changes from normal. However, a 

 better knowledge of the flow field 

 leads to better iceberg reconnais- 

 sance planning. For example, IIP 

 can focus its efforts on an area 

 near the iceberg limit where a 

 large concentration of icebergs is 

 likely. 



The IIP SLAR data suffer some- 

 what from the inability to record 

 digital radar data aboard the 

 aircraft. This is not important for 

 the major features, such as the 

 obvious tonal signal that marked 



69 



