Appendix B 



Introduction 



Forthe first time since 1978, 

 International Ice Patrol conducted 

 hydrographic measurements on 

 the Grand Banks (the data report 

 is still to be published). The 

 cruise was divided into two parts; 

 the first dedicated to a 

 hydrographic survey, and the 

 second to iceberg drift and 

 deterioration. Due to an 

 inoperative Ocean Sampling 

 System (OSS), the hydrographic 

 section of the cruise was 

 conducted using Nansen casts. 



During the 1984 season, eleven 

 satellite- tracked TIROS 

 Oceanographic Drifters (TOD) 

 were deployed in the IIP 

 operating area. Nineof theTODs 

 were deployed from an HC-1 30 

 aircraft during regular ice 

 reconnaisance flights. The 

 remaining two TODs were 

 deployed from the USCGC 

 HORNBEAM, the vessel used to 

 conduct the IIP cruise. The two 

 TODs deployed from 

 HORNBEAM had been 

 recovered after the 1983 season 

 and were reconditioned and then 

 deployed. 



Oceanographic Conditions on the 



Grand Banl<s During the 



1984 International Ice Patrol Season 



Lieutenant lain Anderson, USCG 



TIROS 



Oceanograpliic 



Drifters 



Eleven TODs were deployed 

 during the 1984 IIP season (Table 

 B-1). All of the TODs were 

 deployed with window-shade 

 drogues attached to the TOD by a 

 30m tether. Each TOD was 

 equipped with a sea surface 

 temperature sensor, a drogue 

 tension sensor, and a battery 

 voltage monitor. The position 

 (determined by Doppler shift of 

 the TOD transmitted frequency at 

 the receiver of a polar orbiting 

 satellite) and sensor information 

 from each buoy was obtained 

 through Service ARGOS. 



As of 1 October 1 984, six of the 

 eleven TODs were still drifting in 

 the IIP region (Figure B-1). One 



Table B-1. 



TIROS Oceanographic Drifters Deployed in the 1984 Ice Patrol Season 



Of the TODs (TOD #451 3) failed 

 on deployment and another (TOD 

 #451 4) failed after nine days. 

 Several of the parachute release 

 mechanisms failed to operate 

 properly at deployment. TOD 

 #4509 and #4531 were observed 

 being dragged across the sea 

 surface by an air-filled parachute 

 during the post-deployment 

 overflight. The apparent source 

 of the problem was insufficient 

 voltage in the gel cells used to 

 supply power to the parachute 

 cutters after the salt-water- 

 activated switch closed. The 

 actual fate of the parachutes is 

 uncertain. We assume that when 

 the drogue fully deployed or 

 when the parachute collapsed, it 

 settled into the water and, at 

 worst, became a near-surface 

 drogue. 



There are no significant 

 differences in the velocity 

 distributions for TODs with 

 confirmed parachute releases 

 and those without, suggesting 

 the parachute, if it remained 

 attached did not affect the drift of 

 the TOD (Figure B-2). TOD 

 #2633 and TOD #2632 were 

 deployed from HORNBEAM on 6 

 July and 1 7 July, respectively. 



' Within IIP region 



tPicked up by fishermen on 1 AUG 84 



53 



