Appendix D 



Analysis of IIP Reconnaissance Results 



CDR Ross Tuxhom and MST3 Tristan T. Krein 



Introduction 



International Ice Patrol provides a sea- 

 sonal service of iceberg patrols when the pres- 

 ence of icebergs threatens the North Atlantic 

 shipping routes in the Grand Banks region. 

 Information concerning iceberg conditions 

 near the limits of all known ice is collected 

 primarily from air surveillance conducted by 

 IIP. 



IIP reconnaissance data, as well as ice- 

 berg reports from other sources, is fed into 

 the iceberg drift and deterioration computer 

 models along with ocean current and relevant 

 environmental data. Every twelve hours, the 

 computer models use this information to esti- 

 mate the iceberg positions and determine the 

 limit of all known ice (LAKI). This limit is then 

 broadcast as an ice bulletin and facsimile chart 

 for the benefit of all ships transiting the ocean 

 routes between Europe and North America. 



In 1995 and 1996 data were compiled 

 on the results and effects of iceberg patrols 

 conducted in those seasons. This infomia- 

 tion provides a useful gauge of the effective- 

 ness of IIP reconnaissance efforts and the ac- 

 curacy of the drift and deterioration models. 



Data Collection 



Data on iceberg detections, iceberg de- 

 letions, and changes to the LAKI from iceberg 

 patrols in 1995 and 1996 are shown in Tables 

 1 and 2. The iceberg detection numbers (ice- 

 bergs, growlers, and radar targets) were taken 

 from the flight messages which report the re- 

 sults of each iceberg reconnaissance flight. 



There were forty five (45) and forty six (46) 

 patrol flights in 1995 and 1996, respectively 

 The number of icebergs deleted as a result of 

 each patrol was derived from the process of 

 merging the patrol information into the iceberg 

 computer database. Iceberg deletions from 

 the database involve duty watch officer deci- 

 sion making within parameters set down in 

 "Standing Orders For IIP Operations Center 

 Duty Personnel" (CUP Instruction M3120B). 

 "Change to LAKI" was detemiined by simple 

 comparison of the limits before and after the 

 reconnaissance information was merged into 

 the model and calculation of the area (square 

 nautical miles) added or subtracted by the ad- 

 justments to the LAKI. 



Discussion 



The average number of total iceberg 

 detections per patrol in 1 995 was 54 and in 

 1996 was 19. The difference in these annual 

 averages probably relates to the annual flux 

 of icebergs across 48°N; in 1995, 1432 ice- 

 bergs crossed 48°N while in 1996, 611 ice- 

 bergs crossed that latitude. It is also impor- 

 tant to realize that the variation in iceberg 

 sightings from one patrol to the next is a func- 

 tion of the geographic location of the patrol 

 area; patrols near the LAKI usually yield small 

 counts while patrols farther north result in 

 higher numbers of detections. 



For each of the seasons, the average 

 number of deletions per reconnaissance flight 

 was 7 in 1995 and 11 in 1996. Deletions of 

 icebergs occur when an area is surveyed with 

 acceptable visibility or radar coverage and the 

 patrol does not find icebergs near the pre- 

 dicted position. 



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