Summary 



The IIP iceberg sighting database is not 

 a complete set of all icebergs actually drifting 

 south of 48 North each year. A detailed 

 description of the database contents is con- 

 tained in Attachment 3. Although not com- 

 plete, the Ice Patrol database does represent 

 the most complete and continuous iceberg 

 data set available. 



Over the past 30 years, numerous 

 changes have occurred that effected Ice 

 Patrol's ability to estimate the number of ice- 

 bergs crossing 48 North. As the people at Ice 

 Patrol changed, the methods used to accom- 

 plish manual tasks changed (Examples: de- 

 termining if a report is a resight of an iceberg 

 already being drifted and performing the an- 

 nual counts). Technological advances af- 

 fected, and continue to affect, Ice Patrol's 

 operations and thus the gathering and pro- 

 cessing of data. Bursts of activity in the Ice 

 Patrol area by outside concerns (oil industry, 

 fishing industry, and government agencies) 

 provide increases in the volume of data to be 

 processed. All of these factors have signifi- 

 cantly affected the annual estimate of icebergs 

 crossing 48 North and make difficult direct 

 year to year comparisons. 



Several efforts have been made by a 

 variety of authors to use different methods to 

 classify/rank the severity of a year with regards 

 to icebergs. Although these methods are all 

 based on the estimates of icebergs crossing 

 48 North, the methods do not use definitive 

 numbers as a measure. In 1987, Ice Patrol 

 began classifying season severity (Alfultis, 

 1987). Ice seasons are classified as either 

 light (less than 300 icebergs estimated south 

 of 48 North), intermediate (between 300 and 

 600 icebergs estimated south of 48 North), 

 heavy (between 600 and 900 icebergs esti- 

 mated south of 48 North), or extreme (more 

 than 900 icebergs estimated south of 48 North). 

 Prior to 1 987, the ice seasons were classified 

 by Ice Patrol as light, normal, or heavy by 

 comparing the annual estimate of the number 

 of icebergs crossing 48 North to the long term 

 average. Davidson et al. (1986) describe a 

 severity ranking systemthey used in their work 

 with the data set. This system relies on rela- 

 tive comparison of seasons. 



Hopefully, this paper has provided 

 enough insight into the Ice Patrol iceberg 

 database to allow it to be used within its 

 collection constraints by others. 



Acknowledgements 



I would like to thankthe following people 

 who were a part of Ice Patrol's past for review- 

 ing this paper and helping describe the tech- 

 niques that were used. The years the individu- 

 als served with Ice Patrol follow their names: 



Rudy Lenczyk (1962-1965); John E. Murray 

 (1 965-1 968);CharlesW. Morgan (1969-1971); 

 James R. Kelly (1 969-1 970); David W. Crowell 

 (1972-1975); Steven R. Osmer (1974-1975 

 and 1 987-1 990); Brian Kingsbury (1 979-1 981 ); 

 John J. Murray (1979-1980 and 1990-1992); 

 Alan D. Summy (1982-1983); and Donald L 

 Murphy (1983-Present). 



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