188 



:\rARIOX EXPEDITION TO DAVIS STRAIT AXD BAFFIN BAY 



land, is the most important in causing yearly variation in the number 

 of icebergs. The agency of next importance, about one-third of the 

 Greenland-Newfoundland factor, is the pressure difference. Stykkis- 

 holm-Bergen. The other variates exert so little effect that they 

 warrant no further attention. 



I)Ot)i factors (<"') and {d) were found to be real as shown by the 

 following partial coi'relations: 



facf.d 



-0.32 



Tad. 



= -0.39 



This leads to the development of a regression equation for fore- 

 casting purposes, on the basis : 



(^/) = -0.08 (c')-0.12 (r/)+4.8 



When the calculated value of {a) was plotted for the 47 years, 

 1880-1926, against the actual value of recorded bergs it was found 

 that only in 8 instances did the calculated value differ by more than 

 ±2, on a scale 0—10. The years exhibiting the greatest departures 

 were 1885. 1901. 1905, 1908, 'l909, 1912, 1914. an,l 1924. Such occa- 



§/Z3-*J6789§/2J4567898/23<5«r899/23V567«jS/2J^J6789^ 



S to 2 « o! m 



Icebergs South OF Newfoundland 1880 1930 



Figure 118. — The full line represents the number ut' i(i'l)('r]^'s south of Xewfoundland 

 each year on a scale of 0-10, mean value 4.8. The dashed line is the forecasted 

 number of l)ergs obtained l)y substitution of the necessary meteorological data in 

 the regression equation (p. 188). 



sional abnormalities may be due to any one or all of several causes, 

 for instance, ice jams in the Arctic Archipelago: variations in pre- 

 cipitation; winter storms; summer calms; the breaking away of the 

 fast ice of Melville Bay and, possibly, of that fronting the great 

 Huinl)oldt Glacier. 



The foregoing correlations, and the regression equation con- 

 structed therefrom, have been enq)loyed by the international ice 

 patrol to forecast the number of icebergs that may be expected to 

 drift into the Xorth Atlantic daring the spring. The recent estab- 

 lishment of meteorological stations in Greenlaiul and northern Can- 

 ada, and the prompt receipt of their re))orts by radio permits the 

 use of monthly mean values and the immediate construction of iso- 

 baric maps. In using such in the equation (rt) = —0.08 (c^') —0.12 

 (</)+4.8, Isafjord (Iceland) has been substituted for Stykkisholm, 

 and Julianahaab (Greenland) for lyigtut : c'. therefore represents: 



, ^ 6[(2XDec.-'-»'+Dec.') + (2XJan.''-"'+Jan.') + (Feb.'-»i+Feh.') + (M ar .'-B'+ Mar.' ) ] 

 . (Oct.J-u+Nov.'-»-l-2XDt-c.i-B4-2XJan.i-B) 



Where-'=Isanomaly pressure value for Julianahaab; BI=Isanomaly pressure value for Belle Isle; 

 I = Isanomaly pressure value for Isafjord; and B = Isanomaly pressure value for Bergen. 



