OCEANOGRAPHIC CONDITIONS, 1975 

 D. G. MOUNTAIN 



(U.S Coast Guard Oceanographic Unit) 



Two oceanographic cruises during the. periods 

 2-29 April and 20 May to 10 July were conducted 

 in support of the International Ice Patrol ahoard 

 the USCGC EVERGREEN (WAGO-295). 

 Temperature and salinity data were taken to a 

 depth of at least 1000 meters, or near bottom in 

 shallower water, using a S/T/D Environmental 

 Profiling System. The data were recorded on 

 magnetic tape using a digital data logger, and 

 were processed at sea to yield dynamic height 

 values relative to the 1000 decibar surface. Five 

 separate surveys were completed to yield nearly 

 synoptic dynamic topography (Figures 20 to 24). 



The dynamic topography for the first survey 

 in April (Figure 20) shows the Labrador Cur- 

 rent flowing southward along the eastern edge of 

 the Grand Banks and the North Atlantic Cur- 

 rent flowing northeastward further to the east. 

 This situation is similar to that normally ob- 

 served. However, between the two currents a 

 large anticyclonic (clockwise) eddy is also indi- 

 cated. The eddy likely was shed from the North 

 Atlantic Current. The second survey in April 



(Figure 21) suggests that the eddy moved south- 

 ward and rejoined the North Atlantic Current. 



During the second cruise two surveys with 

 close station spacings (Figures 22 and 24) were 

 conducted for use in verifying a numerical model 

 of the currents and water properties in the area 

 developed by Captain R. C. KOLLMEYER. 

 The Labrador Current changed little from the 

 earlier observations, while the North Atlantic 

 Current entered the survey area from the south- 

 east then turned clockwise to exit to the north- 

 east. The observations between these surveys 

 (Figure 23) suggests that the turning of the 

 current was part of a meander like feature. 



The maximum current in the Labrador Cur- 

 rent calculated from the dynamic topography 

 ranged from 28 to 65 cm/sec at different sections, 

 while the volume transport ranged from 0.77 to 

 7.40, xl0 6 m 3 /sec. In the North Atlantic Current 

 maximum calculated velocities ranged from 45 to 

 75 cm/sec. 



A more complete analysis of this data will be 

 published in the U.S. Coast Guard Oceanographic 

 Report Series (CG-373). 



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