Summary of 

 Operations, 1988 



From April 13 to August 2, 



1988, the International Ice Patrol 

 (IIP), a unit of the U.S. Coast 

 Guard, conducted the International 

 Ice Patrol Service, which has been 

 provided annually since the 

 sinking of the RMS TITANIC on 

 April 15, 1912. During past years. 

 Coast Guard ships and/or aircraft 

 have been patrolling the shipping 

 lanes off Newfoundland within the 

 area delineated by 40"N - 52'N, 

 39"W - 57'W (Figure 1 , inside front 

 cover), detecting icebergs, and 

 warning mariners of these haz- 

 ards. During 1988, Coast Guard 

 HC-130 aircraft flew 40 ice recon- 

 naissance sorties, logging over 

 257 flight hours. The AN/APS-135 

 Side-Looking Airborne Radar 

 (SLAR), which was introduced 

 into Ice Patrol duty during the 

 1983 season, again proved to be 

 an excellent all-weather tool for 

 the detection of both icebergs and 

 sea ice. In addition, the AN/APS- 

 131 SLAR on the Coast Guard 

 HU-25B aircraft was evaluated, 

 and the HU-25B was used opera- 

 tionally for the first time on one ice 

 reconnaissance sortie. 



Aircraft deployments were 

 made on February 17 to 21 , 

 March 3 to 1 6, and March 28 to 

 April 1 to determine the pre- 

 season iceberg distribution. 

 Based on the last pre-season 

 deployment, the 1988 International 

 Ice Patrol season opened on April 

 13. From this date until August 3, 

 1988, an aerial Iceberg Recon- 

 naissance Detachment 

 (ICERECDET) operated from 



Gander, Newfoundland, one week 

 out of every two. The season 

 officially closed on August 2, 1988. 



Watchstanders at HP's 

 Operations Center in Groton, 

 Connecticut, analyze the iceberg 

 sighting information from the 

 ICERECDET, along with sighting 

 information from commercial 

 shipping and Atmospheric Envi- 

 ronment Service (AES) of Canada 

 sea ice/iceberg reconnaissance 

 flights. The IIP Operations Center 

 received 35,129 iceberg sightings 

 from these sources in 1988, 

 compared to 7,031 in 1987. Only 

 those iceberg sightings within HP's 

 operations area (40°N - 52°N, 

 39°W - 57°W) are entered into the 

 IIP iceberg drift prediction com- 

 puter model (ICEPLOT). The 

 watchstanders determine whether 

 the sighting is a resight of an 

 iceberg IIP already has on 

 ICEPLOT, or whether the sighting 

 is of a new iceberg which had not 

 been previously reported. Iceberg 

 sightings near the Newfoundland 

 coast are not entered into the 

 computer model due to lack of 

 ocean current information in the 

 model in these areas to drift the 

 icebergs. Each sighting is labelled 

 in the computer as either a resight 

 or a new sighting. During the 

 1988 ice year, an estimated 1340 

 icebergs were sighted in HP's 

 operations area (south of 52°N), 

 compared to 755 in 1987. 11 60 of 

 these were entered into HP's 

 computer model, compared to 686 

 in 1987. 



HP's computer model 

 consists of a routine which pre- 

 dicts the drift of each iceberg, and 

 a routine which predicts the 

 deterioration of each iceberg. The 

 drift prediction program uses a 

 historical current file to drift the 

 icebergs. This historical data file 

 is modified weekly using satellite- 

 tracked ocean drifting buoy data to 

 take into account local, short-term 

 current fluctuations. Murphy and 

 Anderson (1985) describe the IIP 

 drift model in more detail, along 

 with an evaluation of the model. 



The IIP iceberg deteriora- 

 tion program uses daily wind, sea 

 surface temperature, and wave 

 height information from the U.S. 

 Navy Fleet Numerical Oceanogra- 

 phy Center (FNOC) to melt the 

 icebergs. Appendix C discusses 

 recent improvements FNOC has 

 made to these products. Ander- 

 son (1983) and Hanson (1987) 

 describe the IIP deterioration 

 model in detail. It is the combined 

 ability of the SLAR to detect 

 icebergs in all weather, and the 

 MP's computer models to estimate 

 iceberg drift and deterioration, 

 which has enabled IIP to reduce 

 its ICERECDET operations from 

 weekly deployments to every other 

 week deployments. 



