Appendix E 



Improvements in Ice Patrol's Drifter Program 



Geoffrey A. Trivers and Donald L. Murphy 



Introduction 



Since 1 976, International Ice Patrol (IIP) 

 has deployed satellite-tracked drifting buoys 

 near the Grand Banks off Newfoundland, 

 Canada. The buoys provide ocean current 

 and sea surface temperature data for Ice 

 Patrol's iceberg drift and deterioration models. 

 From the program's inception through 1991, 

 most of the buoys were 2 m spar hulls with 

 window-shade drogues suspended 50 m be- 

 low the surface. In the early years, the buoys 

 were deployed from Ice Patrol research ves- 

 sels, but starting in 1 979, they were launched 

 from U. S. Coast Guard HC-1 30s during regu- 



larly scheduled iceberg reconnaissance flights 

 (See Fig. 1). An airborne delivery system 

 allows Ice Patrol to monitor the currents 

 throughout the ice season, and permits great 

 flexibility in determining the buoy deployment 

 locations and times. 



The spar buoys, together with their air- 

 deployment packages, are large, heavy and 

 expensive. By 1990, a buoy rigged for air- 

 deployment cost about $12,000-$1 4,000. In 

 the same year, oceanographers completed 

 development of a small, inexpensive buoy that 

 had superior drift characteristics to the 2 m 

 spar buoy (Sybrandy and Niiler, 1991). It 

 consists of a 35 cm diameter spherical surface 



Figure 1 . Scheme for Airborne Deployment of WOCE Buoy 



AIRDROP 



PARACHUTE 

 RELEASE 



SATELLITE 



BEACON SIGNAL 



CURRENT 



81 



