THE CORRELATION BETWEEN WINTER FROST DEGREE DAYS OF SELECTED BAFFIN ISLAND- 

 LABRADOR-NEWFOUNDLAND COASTAL STATIONS AND THE RELATIVE SEVERITY OF THE 

 GRAND BANKS ICEBERG SEASON 



The previous section discussed the excellent correlation between 

 winter winds and the subsequent Grand Banks iceberg season. It is 

 only natural to also investigate the possible correlation between the 

 winter climate of areas inhabited by the berg crop as it travels from 

 Baffin Bay in the Baffinland-Labrador Current system toward the 

 Grand Banks. While air temperature per se has no direct influence 

 on the movement of icebergs, it does have a direct, as well as an 

 indirect, influence in determining the environment of icebergs. Gen- 

 erally, colder than normal air temperatures will directly effect a 

 colder environment for the above-water portion of icebergs and will 

 indirectly effect a colder water environment, possibly for the duration 

 of the bergs' lifetime. Colder air temperatures will generally result 

 in a greater abundance of pack ice and a colder Baffinland-Labrador 

 Current and bergs will probably travel with this colder environment to 

 the Grand Banks. Thus the berg supply can be expected to arrive at 

 the Grand Banks in greater numbers and larger sizes during cold 

 years. It is true that colder air temperatures do coincide with winds 

 from the west and northwest during frequent outbreaks of polar air 

 masses in the winter along the Baffin Island, Labrador, and New- 

 foundland coasts. If winds from the opposite southeast or east 

 quadrant had the colder temperatures, correlation between air tem- 

 peratures of the relative severity of the Grand Banks iceberg season 

 would be very poor. Thus, it must be admitted that if correlation is 

 good, it is partially incidental as colder temperatures will naturally 

 accompany the westerlies and northwesterlies which are most favor- 

 able for transporting ice towards tlie Grand Banks. Inasmuch as 

 the average winter air temperatures in the region will considerably 

 influence the berg crop environment along the entire route, a con- 

 siderable influence on the deterioration and survival of the berg crop 

 can be assumed. If good correlation is developed between average 

 ^\•inter air temperatures and the relative severity of Grand Banks 

 iceberg season, this correlation can be useful as another indication in 

 iceberg forecasting. 



An excellent indication of the winter climate in the critical northern 

 areas can be obtained by considering the temperatures of key weather 

 stations there. A quantitative determination of the climate at a 

 given station for a given period can be made by computing the accu- 

 mulation of frost degree days. A frost degree day is defined as a day 

 with a mean temperature 1° F. below an arbitrary base. A day with 

 an average temperature of 24° F. results in an accumulation of 8 frost 

 degree days (FDD) if the base of 32° F. is used. See table IV for 

 data on accumulated frost degree days for selected key stations 1956- 



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