SUM EC S Lab t EC Grand Banks Weekly Ice Coveiatje For 200405 



■ice coverage 



- current his tori: 

 late 133051 



ear3:l'J*a/69-2004/35 



historic dates: 

 1126-0716 



Figure 23. Normalized ice coverage in east-Newfoundland waters in 2005 (Canadian Ice Service, 2005) 



Apr 1-Junc 1 (r=0.82)." Peterson (2004) 

 used the relationship between sea ice and 

 iceberg populations to develop a long- 

 range iceberg-forecasting system. The 

 early part of 2005 presented a formidable 

 challenge to the forecast technique. 

 Based on the near-normal early sea-ice 

 growth, the forecast system predicted a 

 medium (near normal) population of 

 icebergs for February and March (I.K. 

 Peterson, personal communication, April 

 2006), yet a sparse population was 

 observed. 



Finally, the winter 2005 

 (December 2004-March 2005) North 

 Atlantic Oscillation index was weakly 

 positive, 0.12 (Hurrell, 2006), offering no 

 evidence that an unusually light iceberg 

 year was forthcoming. Hurrell (2006) 

 calculates the NAO index using the 

 difference of normalized sea-level 

 pressure between Lisbon, Portugal, and 



Stykkisholmur/Rcykjavik, Iceland. The 

 NAO, the dominant mode of winter 

 atmospheric variability in the North 

 Atlantic, flucUiatcs between positive and 

 negative phases. The positive phase is 

 associated with meteorological conditions 

 that favor the movement of icebergs into the 

 shipping lanes. These conditions include 

 strong northwest winds along the Labrador 

 coast, which bring colder-than-normal air 

 temperatures and greater-than-normal sea- 

 ice extent. In addition, the persistent 

 northwest winds promote southward iceberg 

 movement. Warmcr-than-normal conditions 

 and less extensive sea ice off the Labrador 

 coast arc associated with the negative NAO 

 phase. The 0.12 NAO index value was 

 essentially neutral — that is, the atmospheric 

 conditions were neither very favorable nor 

 unfavorable to the southward transport of 

 icebergs into the North Atlantic shipping 

 lanes. 



22 



