Paper 15 



shallow eddy waters the deeper circulation seemed to be closed. 

 The shara thermal front on the shoreward side of the eddy 

 (Fig. 15. 1A) indicated considerable velocity shear. In 

 mid-De cember r the eddy was located at 70w30* and had an apparent 

 surface diameter of 80 nm (15 km). This eddy persisted into 

 1977 until captured by the Gulf Stream during February. 



Eddy 76E (Fig. 15.5) formed about 

 elliptical meander _ 

 surface diameter at this time 

 eddy 



.-. 26 May at 62W from an 



that looped westward from 6CW. Its apparent 

 was about 80 nm (15C km) 



This 

 a 

 e 



suiidte uicimtTLer dt tnis Ljmtr wdi auoux ou nm ^.IDU Km^. inis 

 eddy survived at least into late July^ when it became masked by a 

 large area of warm surface water. It may have lasted through the 

 better part of Augusts but the fate of eddy 76E is obscure. 

 Presumably^ it coalesced into either the Gulf Stream or eddy 76D. 



Eddy 76F (Fig. 15.6) formed from a northward extending meander at 

 64W on 15 October. Its apparent surface diameter was about 80 nm 

 (150 km). It survived until February 1977. 



Eddy 76G (Fig. 15.7) formed about 27 October from a meander that 

 had looped westward from 65W with an apparent surface diameter of 

 90 nm (170 km). After initial westward movements the eddy 

 remained fairly stationary during December at 67W30'. This eddy 

 persisted until well into 1977. 



ZONAL ANALYSIS OF EDDY POSITIONS AND MOVEMENTS 



A zonal analysis of all the eddies in 1976 is summarized in 

 Table 15.2 to reveal their movements relative to one another. 

 The region studied was divided into eight zones of about equal 

 lengths along the axis of eddy movements (Fig. 15.15). The zonal 

 boundaries were drawn approximately normal to both the mean 

 position of the Gulf Stream's north wall and the lOQ-fm (180-m) 

 isobath. The zone in which each eddy occurred at the middle of 

 each month is shown in Table 15.2. 



Eddy positions with respect to zone were also determined for 1974 

 and 1975 from Bisagni (see footnote 2). The last column of 

 Table 15.2 gives the number of occurrences at midmonth for the 

 years 1974-76 in each zone. Thusr in zone 4^ eddies were present 

 at midmonth 15 times out of a possible 36. 



Except for zones 1 and 8/ overall eddy activity was fairly 

 uniform with respect to zone for the years considered. There are 

 relatively few occurrences in zone 8 because many eddies never 

 get that far and those that do are soon incorporated into the 

 Gulf Stream. The low level of activity in zone 1 seems to be 

 realr even though partly a data artifact caused by excessive 

 cloud interference in the satellite coverage. Occasional cloud 



265 



