Appendix C 



Limit-Setting Iceberg Report for 1996 Season 



CDR Ross Tuxhom and MST2 L. Scott Howell 

 Introduction Data Collection 



International Ice Patrol's mission is to 

 identify the Limits of All Known Ice (LAKI) and 

 to transmit this information to mariners at sea. 

 During the ice season, the key element of IIP 

 operations is to conduct reconnaissance pa- 

 trols to determine the location of icebergs that 

 establish the LAKI. 



The LAKI is based on all known ice- 

 berg and sea ice information and represents 

 the extent of iceberg danger in the vicinity of 

 the Grand Banks of Newfoundland. From 

 Newfoundland, the line marks the southwest- 

 em, southern, and southeastern limits of the 

 iceberg region, and ends at an intersection 

 point with latitude 52°N. Over the last twenty 

 years, at its extremes, the LAKI has extended 

 in the northwestern Atlantic Ocean as far south 

 as latitude 39°N, and in the east to longitude 

 37°W. 



Limit-setting icebergs are those ice- 

 bergs that form the vertices of the LAKI. In- 

 ternational Ice Patrol in recent years has col- 

 lected data to learn more about these impor- 

 tant icebergs. Analysis of this data has indi- 

 cated the large relative contribution of 

 sightings from IIP reconnaissance flights in 

 this critical area near the limits. 



The information pertaining to the limit- 

 setting icebergs is important as a measure of 

 effectiveness of HP's surveillance efforts in 

 locating the iceberg hazard. It is HP's goal to 

 continuously improve its mission performance 

 by effectively locating the icebergs that con- 

 stitute the LAKI and accurately provide this 

 information to ships to enable them to avoid 

 encountering icebergs. 



Limit-setting icebergs were categorized 

 as eastern, southern, and western by the side 

 of the LAKI "polygon" where they occurred. 

 For the majority of cases, the three catego- 

 ries of icebergs were distinct populations. The 

 few exceptions were when icebergs drifted 

 from the southern limit to the eastem limit. In 

 those instances the iceberg's designation was 

 changed accordingly. 



Data on the limit-setting icebergs were 

 gathered daily from the output of the Iceberg 

 Data Management and Prediction System 

 (DMPS). Icebergs were recruited as limit-set- 

 ters either from the 1200Z Ice Bulletin list of 

 "icebergs not in area of many bergs" or from 

 iceberg sightings by the various sources at or 

 near the LAKI. Each day, the icebergs in the 

 limit-setter database were accounted for The 

 attributes of those icebergs were checked to 

 ascertain any resights or deletions, and any 

 changes were recorded. The following infor- 

 mation was determined for each of the desig- 

 nated limit-setting icebergs: 



1 . DMPS iceberg number. 



2. Days on plot in DMPS model. 



3. Days as a limit-setting iceberg. 



4. Source of sighting when entered in 

 limit-setter database, and any subsequent 

 resighting source. 



5. Location on LAKI — W, S, E. 



6. Method of deletion: Collection of 

 data on a given limit-setting iceberg ended 

 when it was deleted from DMPS by standard 

 IIP criteria. There are two ways by which IIP 

 removes an iceberg from DMPS: 



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