Appendix D 



Analysis of IIP Reconnaissance Results 



CDR Stephen L Sielbeck and MST2 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 near the Grand Banks of New- 

 foundland. Information concerning iceberg 

 conditions near the limits of all known ice is 

 collected primarily through air surveillance 

 conducted by IIP. 



IIP reconnaissance data, iceberg re- 

 ports from other sources, ocean currents and 

 relevant environmental data are used by ice- 

 berg drift and deterioration computer models. 

 Every twelve hours, the numerical models 

 estimate iceberg positions and determine the 

 limit of all known ice (LAKI). This limit is broad- 

 cast as ice bulletins and facsimile charts to 

 ships crossing the Atlantic Ocean between 

 Europe and North America. Data collected 

 from each of the 1997 ice season patrol flights, 

 when used with similar data from the 1995 

 and 1996 seasons (Table 1), provide a useful 

 gauge of the effectiveness of IIP reconnais- 

 sance efforts and the accuracy of drift and 

 deterioration models. 



Data Collection 



Data on iceberg detections, iceberg de- 

 letions, and changes to the LAKI from iceberg 

 patrols in 1997 are shown in Table 2. The 

 iceberg detection numbers (icebergs, growl- 

 ers, and radar targets) were taken from the 

 flight messages reporting results of each ice- 

 berg reconnaissance flight. There were fifty 

 five (55) patrol flights in 1997. The number of 

 icebergs deleted as a result of each patrol was 



derived from the process of merging the pa- 

 trol information into the iceberg computer da- 

 tabase. Iceberg deletions from the database 

 involve duty watch officer decision making 

 within parameters set down in "Standing Or- 

 ders For IIP Operations Center Duty Person- 

 nel" (CMP Instruction M3120B). Changes to 

 LAKI, calculated in square nautical miles, were 

 determined by simple comparison of the lim- 

 its before and after reconnaissance informa- 

 tion were merged into the model. 



Discussion 



The iceberg population in the vicinity 

 of the Grand Banks varies annually with re- 

 spect to numbers, density and distribution. 

 The limits of all known ice are normally de- 

 fined by a small number of icebergs. The av- 

 erage number of iceberg detections per pa- 

 trol in 1997 was 14 and the average number 

 of deletions was 8 icebergs. The variation in 

 iceberg sightings from one patrol to the next 

 is a function of the geographic location of the 

 patrol area; patrols near LAKI usually yield 

 small counts while patrols farther north result 

 in higher numbers of detections. Deletions 

 occur when an area is surveyed with accept- 

 able visibility or radar coverage and the patrol 

 does not find any ice near predicted iceberg 

 positions. 



The change of ocean area enclosed 

 by LAKI resulting from reconnaissance patrols 

 in 1997 is depicted in Figure 1. Increases in 

 area indicate iceberg detections close to or 

 outside LAKI, conversely, decreases result 

 from an absence of icebergs at predicted lo- 

 cations. Of 55 patrols, 22 reduced and 5 in- 

 creased the area defined by LAKI. The re- 



46 



