Discussion of Iceberg and 

 Environmental Conditions 



The number of icebergs that pass 

 south of 48°N in the International 

 ice Patrol area each year is the 

 measure by which International Ice 

 Patrol has judged the severity of 

 each season since 1912 (Table 1). 

 With 204 icebergs south of 48°N, 

 1986 is the 49th most severe year 

 on record, a relatively light year. 



Since the number of icebergs 

 calved each year by Greenland's 

 glaciers is in excess of 10,000, a 

 sufficient number of icebergs exist 

 in Baffin Bay during any year. 

 Therefore, annual fluctuations in 

 the generation of Arctic icebergs is 

 not a significant factor in the 

 number of icebergs passing south 

 of 48''N annually. The factors that 

 determine the number of icebergs 

 passing south of 48°N each 

 season can be divided into those 

 affecting iceberg transport (cur- 

 rents, winds, and sea ice) and 



those affecting iceberg deteriora- 

 tion (wave action, sea surface 

 temperature, and sea ice). 



Sea ice acts to impede the trans- 

 port of icebergs by winds and 

 currents and also protects ice- 

 bergs from wave action, the major 

 agent of iceberg deterioration. 

 Although it slows current and wind 

 transport of icebergs, sea ice is 

 itself an active medium, for it is 

 continually moving toward the ice 

 edge where melt occurs. There- 

 fore, icebergs in sea ice will 

 eventually reach open water 

 unless grounded. The melting of 

 sea ice itself is affected by snow 

 cover (which slows melting) and 

 air and sea water temperatures. 

 As sea ice melt accelerates in the 

 spring and early summer, trapped 

 icebergs are rapidly released and 

 then become subject to normal 

 transport and deterioration. 



Acknowledgements 



Commander, International Ice 

 Patrol acknowledges the assis- 

 tance and information provided by 

 the Canadian Department of the 

 Environment, the U.S. National 

 Weather Service, the U.S. Naval 

 Weather Service, and the U.S. 

 Coast Guard Research and 

 Development Center. 



We extend our sincere apprecia- 

 tion to the staffs of the Canadian 

 Coast Guard Radio Station St. 

 John's, NewfoundlandA/ON, the 

 Gander Weather Office, the per- 

 sonnel of U.S. Coast Guard Air 

 Station Elizabeth City, and the 

 USCGC EVERGREEN for their 

 excellent support during the 1986 

 International Ice Patrol season. 



It is also extremely important to 

 recognize the efforts of the 

 personnel of the International Ice 

 Patrol: 



CDR N.C. Edwards, Jr., Dr. D.L. 

 Murphy, LT F. J. Williams, LT I. 

 Anderson, LTJG N.B. Thayer, 

 MSTCS G.F. Wright, MSTC D.A. 

 Eichmann, MST1 M.G. Barrett, 

 YN1 S.A. Cooper, MST1 K.O. 

 Pelletier, MSTI R. J. Uebelacker, 

 MST2 A.A. Anzelmo, f^ST2 D.A. 

 Hutchinson, MST2 R.L. Franco, 

 MST2 J.K. Silves, MST3 W.A. 

 Henry, MST3 K.A. Martin, MST3 

 C.F. Weiller. 



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