40N 



■1 : 3 5 «■ 



-+- 1 1 r 52N 



50 



-- 45 



-+- 



4 ON 



57U 



55 



50 



45 



40 39W 



Figure B-lc Drift trajectories of buoys 4547 and 4552, marked with Juiian dates. 



described above. The fact that 

 the parachute did not cut free after 

 the buoy entered the water means 

 that the buoy also had a near- 

 surface parachute drogue. It is 

 likely that the parachute wrapped 

 around the buoy hull as happened 

 with a 1985 buoy (Anderson, 

 1985). Although the track of 4552 

 should be viewed with caution, the 

 fact that the parachute remained 

 attched to the buoy is probably not 

 an important factor. 



4547 



Buoy 4547 was deployed from an 

 HC-130 on 12 June 1986 (163) in 

 the northwestern section of the Ice 

 Patrol region in position 50°59.0'N 

 53°00.0'W (Figure B-lc). After its 

 deployment, 4547 drifted north- 

 east at 16 cm/s until 1 July (182). 



On 1 July, it moved south then 

 east with the Labrador Current 

 until about 9 August (221). On 

 this date, the temperature in- 

 creased from about 9°C to 1 1°C 

 and drifter 4557 rrwved northeast 

 and then southwest at 21 cm/s 

 until its recovery by USCGC 

 NORTHWIND on 26 August (238). 



The drogue sensor indicated the 

 drogue became disconnected on 

 the day after its deployment. 

 When the buoy was recovered by 

 NORTHWIND on 26 August 1986 

 (238) only about 10 meters of the 

 tether still attached to the drifter. 

 Inspection of the tether after 

 recovery indicated the tether may 

 have been cut. The prolonged low 

 and inconsistent direction of the 

 drift indicated early drogue loss 



during the deployment. This was 

 another case where the drogue 

 sensor reliably reported the 

 drogue status. 



Discussion 



The tracks from this year's drifters 

 illustrate the current variability of 

 the Ice Patrol region. The pre- 

 sense of the oceanic front south of 

 the Flemish Cap greatly influenced 

 the movement of all drifters 

 coming through Flemish Pass. In 

 past years, drifters moving south 

 through Flemish Pass have gone 

 as far south as 42°N (Anderson 

 1984 and 1985). This year the 

 farthest south a drifter travelled 

 was about 44°N (4552). This 

 difference can be attributed 

 directly to the front. 



49 



