U. S. Coast Guard Communications Station 

 Boston, Massachusetts, NMF/NIK, was the 

 primary radio station used for the transmission 

 of the daily ice bulletins and facsimile charts 

 after preparation by the Ice Patrol office in New 

 York. Other transmitting stations included 

 Canadian Coast Guard Radio Station St. 

 John's/VON, Canadian Forces Radio Station 

 Mill Cove/CFH, and U. S. Navy LCMP Broadcast 

 Stations Norfolk/NAM, Thurso, Scotland, and 

 Keflavik, Iceland. 



Canadian Forces Station Mill Cove/CFH as 

 well as AM Radio Station Bracknell/GFE, 

 United Kingdom are radio facsimile broad- 



casting stations which used Ice Patrol limits in 

 their broadcasts. Canadian Coast Guard Radio 

 Station St. John's/VON provided special broad- 

 casts. 



The International Ice Patrol requested that all 

 ships transiting the area of the Grand Banks 

 report ice sightings, weather, and sea surface 

 temperatures via U. S. Coast Guard Com- 

 munications Station Boston, NMF/NIK. 

 Response to this request is shown in Table 3 

 and Appendix A lists all contributors. Com- 

 mander, International Ice Patrol extends a 

 sincere thank you to all stations and ships 

 which contributed. 



Table 3 



Number of ships furnishing Sea Surface Temperature (SST) reports 



Number of SST reports received 



Number of ships furnishing ice reports 



Number of ice reports received 



First Ice Bulletin 



Last Ice Bulletin 



Number of Facsimile Charts transmitted 



80 



334 



84 



148 



220000Z FEB 83 



260000Z AUG 83 



195 



The Coast Guard acquired a new Side- 

 Looking Airborne Radar (SLAR) in October 

 1982, which was used extensively during the 

 1983 season. It is a model AN/APS-135 

 manufactured by Motorola, Inc., and replaces 

 their older AN/APS-94D which was used on 

 Coast Guard C-130 aircraft. The AN/APS-135 is 

 a vast improvement over the AN/APS-94D. It 

 proved to be an excellent tool for the detection 

 of sea ice and icebergs, especially in low 

 visibility conditions. In past years, the success 

 of Ice Patrol reconnaissance flights were 

 dependent upon good visibility in the search 

 area. The new SLAR allowed the plane crew to 

 search a certain area, regardless of the visibili- 

 ty conditions. The results from the SLAR were 

 not as reliable as a good visual search due to 

 the inability to positively identify and describe 

 icebergs detected. But the weather conditions 

 in Newfoundland and the Grand Banks are 

 usually poor, forcing an aircraft without SLAR 

 to remain on the ground twice as often, 

 awaiting good visibility. This is no longer 

 necessary with the AN/APS-135 SLAR. 



The AN/APS-135 was first tested for use in 

 iceberg detection during the pre-season 

 deployment in January 1983. The International 

 Ice Patrol detected a large amount of sea ice 



and icebergs in the Grand Banks area on this 

 deployment, bringing the opening of the 1983 

 season in February 1983, earlier than normal. 

 SLAR testing to determine optimum range and 

 altitude for berg detection was scheduled for 

 February, but these plans had to be cancelled 

 in order to fly actual patrols to determine the 

 limits of all known ice. Based on the informa- 

 tion provided by Motorola, Inc. and preliminary 

 operational testing, the optimum aircraft 

 search altitude for SLAR was found to be 

 8000-10000 feet. A range of 27 miles either side 

 of the aircraft appeared to be optimal for detec- 

 tion accuracy. It must be pointed out that IIP 

 was unable to obtain any ground truth informa- 

 tion on SLAR contact types and sizes detected 

 by the SLAR. Visual confirmation of contacts 

 was made from the aircraft whenever possible 

 and some ground truthing of small boats and 

 ships had been done in warmer waters. Based 

 on these comparisons, SLAR operators ana- 

 lyzed contacts on the SLAR film to differentiate 

 ships from bergs and estimate iceberg sizes. 



The addition of the AN/APS-135 SLAR led 

 Commander, International Ice Patrol (CMP) to 

 alter the normal routine of patrols. On a clear 

 day the optimum altitude for a visual search is 

 2000 feet. The SLAR, however, works best at 



