BUOY PERFORMANCE 

 TABLE B-2 . 1989 Operational Buoy Performance 



BUOY 



NUMBER OF DAYS 

 IN IIP OPERA 



NUMBER OF DAYS 

 DROGUE CONNECTED 



NUMBER OF DAYS BUOY 

 TRANSMrTTED (AS OF 1 SEP 90) 



204 



5 



174 







187 



158 



108 



55 



175 



273 



5 



305 



372 (beached Scotland) 

 187 



465 (t)eached England) 

 316 (iDeached Ireland) 



60 

 453 (still transmitting) 



Average 94 



•Failed within IIP OPAREA 



118 



271 



compaction of sea ice could damage 

 a buoy. The period of transmission 

 of three buoys was ended not due to 

 failure but by beaching in Europe, 

 and 4570 was still transmitting on 1 

 September 1990. Three of the nine 

 buoys (9876, 4537, 4567) failed 

 prematurely (transmitted less than 

 90 days). Data transmitted from 

 these three indicated that the battery 

 voltage was within the operational 

 limits at the time of failure. The 

 cause of the failures is unknown. 



Data from the drogue sensors indi- 

 cated that the average number of 

 days a drogue remained connected 

 was 118. The average is 1 25 if 9876 

 and 4537 are excluded since these 

 buoys stopped transmitting before 

 the drogues disconnected, and the 

 average is 146 if 9879 is also ex- 

 cluded since its sensor indicated 

 that the drogue was never con- 

 nected. Data from buoy 9879 is 

 viewed as suspicious. 



Although the data on buoy perfor- 

 mance show that the drogues dis- 

 connect much soonerthan the buoys 

 stop transmitting, the average 

 number of days the drogue is con- 

 nected is sufficient for IIP purposes 



since this is greaterthanthe average 

 time the buoy remains within the IIP 

 area. 



SUIVIMARY AND CONCLUSIONS 



Contrary to the 1988 season, none 

 of the buoys deployed during 1989 

 were recovered at sea. 



I^ost of the 1989 buoy trajectories 

 followed familiar patterns. For ex- 

 ample , buoys drifting within the 1 000- 

 m contour (4569, 4568) passed 

 through the Flemish Pass along this 

 contour. However, buoys offshore 

 of the 1 000-m contour (9875, 4565) 

 did not pass through Flemish Pass 

 but curved northward and moved 

 north of Flemish Cap. 



The Labrador Current's temporal 

 variability resulting from a warm- 

 core eddy near 44N and the eastern 

 Grand Banks was observed again in 

 1989. A warm-core eddy appeared 

 to deflect the Labrador Current 

 eastward in early May (buoys 4537 

 and 4567) , but there was no evidence 

 of such an eddy in July (buoy 4569). 

 METOC Sea surface temperature 

 charts for 9 to 18 May (129 to 138) 

 also suggest the existence of a 



warm-core eddy which could have 

 influenced the buoys. A warm-core 

 eddy has been observed in the same 

 position, deflecting the Labrador 

 Current, in May during previous IIP 

 seasons and is discussed in more 

 detail in Murphy (1987). 



The trajectories of buoys 4565 and 

 4569 both had anticyclonic loops of 

 similar size in nearly the same lo- 

 cation north of Flemish Cap. Speeds 

 for the two buoys while in these 

 loops were also comparable. The 

 temperatures for 4565 were lower 

 than those for 4569. This tempera- 

 ture difference is probably due to 

 4565 making its loop about 80 days 

 earlier. Note that the two buoys 

 made these loops in approximately 

 the same location despite taking very 

 different paths prior to that. 



Page 67 



