of low SST (15.5°C) and sonic layer depth (SLD) greater than that of 
the adjacent warm water. 
The flight of 28 January 1969 (figure 2) again shows a cold 
tongue (SST<13°C) intruding from the west along the edge of the Gulf 
Stream. A cold pocket (SST<13°C) is located seaward of the Continental 
Shelf. Downstream from the cold tongue, the Gulf Stream boundary be- 
came quite diffuse with a poorly defined tongue of warm water (SST>17°C) 
inshore of the stream. A thermal front (SST: 7° to 13°C) is located 
adjacent to the edge of the Continental Shelf in the western half of 
the survey area. This front was in evidence in less-developed form 
during flights on 17 and 20 December 1968 and 29 January 1969 (figures 
15 through 17, appendix). BT D is typical of thermal structure im- 
mediately south of the northern edge, with Gulf Stream water (SST>22°C) 
_in the near-surface layer underlain by a temperature inversion between 
n> 100 and 140 meters. BT's E, F, and G represent warm water inshore of 
“the Gulf Stream, Slope Water within the cold pocket, and warm water 
overlying Slope Water near the Continental Shelf, respectively. 
The most unusual feature of the 9 April survey (figure 3) is the 
southerly location of the Gulf Stream, particularly east of 74°W. 
Other features of interest are a large cold tongue (SST<11°C) intruding 
into the survey area from the west and the presence of warm water (>19°C) 
in the northeastern quadrant of the area. A strong temperature gradi- 
ent is evident between the warm water and the cooler water to the west 
(6°C in less than 30 km). BT's H and I, dropped on opposite sides of 
the gradient, show the strong seasonal thermocline and shallow SLD in 
the warm water compared to the nearly positive gradient and relatively 
deep SLD in the cold water. The next two BT's (J and K) illustrate 
boundary and Gulf Stream water, respectively. 
Major features observed during the 30 April flight (figure 4) were 
generally similar to those observed during the 9 April flight except 
for northerly displacement of the northern edge. Inclement weather 
prevented expansion of the flight pattern to determine if the warm areas 
were separated from the northern edge by a cold intrusion. Bilseelermen ts 
and N represent thermal structure in the northern edge, in the warm 
area, and in the cold tongue, respectively. 
The final two flights of the survey were flown within a 4-day 
period in May, thus providing an excellent picture of short-term vari- 
ation within the study area. Analysis of the flight of 12 May (figure 
5) shows warm water (SST>22°C) inshore of the Gulf Stream west of 74°W. 
The warm area was approximately 40 meters thick (BT P). Of particular 
interest is a cold intrusion (SST<13°C) extending from the northwestern 
quadrant of the survey area to a position adjacent to the northern edge 
at 74°W and remaining in contact with the northern edge throughout the 
remainder of the study area. BT Q, dropped within this narrow band of 
cold water, shows this feature and underlying temperature inversions to 
