turer. The parachutes are packed and rigged 

 by Coast Guard Air Station, Elizabeth City, 

 North Carolina, the base of the HC-1 30 recon- 

 naissance aircraft used for Ice Patrol. The 

 straps are sewn by a local sail-maker. Finally, 

 the package is assembled by Ice Patrol ma- 

 rine science technicians. 



Drifter Deployments 



Thus far, IIP has deployed ten WOCE 

 drifters, two in 1992 and eight in 1993. Both 

 the 1992 drifters were deployed from ships 

 and were eventually recovered. One buoy, 

 2579, was recovered after 307 days of drift, 

 the other, 2589, after74days. The operational 

 air-deployments started in 1993, with seven 

 buoys launched from HC-1 30s. One buoy 

 (2586) was deployed from a ship. None of the 

 1993 buoys have been recovered. Table 1 

 summarizes the deployments. 



All the operational air deployments 

 were filmed and in all cases the aircraft circled 

 the drop site to ensure that the buoy came out 

 of the package. In one case, 2584, the para- 

 chute failed to open, resulting in a 300-foot 

 free-fall to the surface. The buoy was ob- 

 served to have come out of the package and it 

 is still transmitting, although the drogue appar- 

 ently detached 1 25 days after deployment. 



There were a few cases in which the 

 package splashed down before the parachute 

 detached. In these cases, the buoy was 

 observed to have come out of the package. 



Buoy 2583 stopped transmitting two 

 days after its deployment, despite the fact that 

 the air launch was completely successful. 

 There was an unexplained, rapid decline in the 

 battery voltage. The remainder of the buoys 

 provided records that were long enough for IIP 

 operations, with an average lifetime of about 6 

 months (as of 1 November 1993). According 

 to the submergence sensor, the drogue is not 

 surviving as long as the buoy transmits, with 

 an average drogue life of about 4 months 



(again, as of 1 Nov 1993). Since the time that 

 a buoy remains in the Ice Patrol operations 

 area (40-52 N, 39-56 W) is 3 to 4 months, this 

 performance is satisfactory for IIP operations. 

 However, the issue of the premature drogue 

 failures needs to be explored. 



Buoy drift data are presented in the Ice 

 Patrol's 1993 Oceanographic Drifting Buoy 

 Atlas, which is available upon request. 



Summary 



Ice Patrol has developed a reliable and 

 inexpensive air-deployment package for 

 WOCE drifters. The design is relatively simple 

 and the package seems to be robust enough 

 to survive high-speed air-deployment. There 

 seems to be sufficient redundancy in the self- 

 deployment system. Two tests and observa- 

 tions following seven operational deployments 

 show that the buoys are coming out of the 

 boxes. The drifters themselves appear to be 

 robust, even able to survive a 300-foot free- 

 fall. They are performing well once in the 

 water, although further work needs to be done 

 on the matter of drogue survival. Specifically, 

 we hope to recover more drifters to determine 

 the causes of the drogue failures. 



Ice Patrol plans to deploy twelve to 

 fifteen WOCE drifters during 1994. Most will 

 be launched from aircraft using its newly de- 

 veloped air-deployment package. 



References 



Sybrandy, A. L and P. P. Niiler, 1991. 

 WOCE/TOGA Lagrangian Drifter Construc- 

 tion Manual. WOCE Report Number 63. Ref- 

 erence 91/6 Scripps Institution of Oceanogra- 

 phy, LaJolla, CA 92093, 58pp. 



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