60 



MAEIOISr EXPEDITION" TO DAVIS STRAIT AND BAFFIN BAY 



thus to aA^oid any liability to bias. The correlation between the 

 winter atmospheric gradient, Ivigtut to Belle Isle, and the spring 

 crop of pack ice south of Xewfoiindland w^as found to be +0.86. 

 (See pp. 180-189.) 



Brooks and Quennell (19-28, p. 33) besides investigating the etfect 

 of Arctic and Greenland Sea ice on European weather also studied 

 the efl'ect of varying masses of pack ice and cold water introduced 

 off Newfoundland. They found : 



1. Much pack ice off Newfoundland in the spring. April to June, 

 tends to occur with low atmospheric pressure for the same period at 

 Iceland and high pressure at the Azores. 



2. Much pack ice off Newfoundland in the spring tends to be fol- 

 lowed nine months later by high pressure over northern Norway and 

 low pressure over southern England. 



3. Much pack ice off Newfoundland in the spring tends to be fol- 

 lowed 15 months later b}^ high pressure at the same places as (2). 



Finally, the effect of ice off Newfoundland on the pressure over 

 w^estern Europe is generally similar to that of the polar cap ice and 

 of the Greenland Sea pack, but as might be supposed, is much less 

 pronounced. The correlation coefficients between ice off Newfound- 



Pack-Ice Graph for the Western North Atlantic 



Figure 30. — A graph representing the relative amounts of pack ice south of New- 

 foundland by years, 1880-1927. The data upon which this graph is based was 

 taken from Mecking (1906) for the years 1880-1900, and since then from the 

 records and the researches of the international ice patrol. 



land, April to June, and pressures at Vardo, Valencia, and Berlin, 

 June to March, of 30, 20, and 31, respectively, are not high, yet may 

 have some small value for forecasting European weather. 



LAND ICE 



Glacier ice, formed from precipitation on land, is of great impor- 

 tance as the source of icebergs. Under the present distribution of 

 temperature and snowfall over the earth, the permanently ice- 

 decked lands lie mostly within the polar regions. The greatest single 

 ice sheet in the Nortliern Hemisphere is that which overlies Green- 

 land, in area equal to all lands east of the Mississippi Kiver and south 

 of the St. Lawrence River. Greenland is the principal source of the 

 icebergs that are found drifting in the North Atlantic and in its 

 tributary seas. 



The treatment of icebergs must necessarily include their general 

 distribution in time and place, their form, size, color, markings, 

 volumes of flotation, manner of disintegration, etc., all depending to 

 a great degree upon conditions which existed long before the ice- 

 berg was born. Chamberlin, Drygalski, Koch, Priestley, de Quer- 

 vain, Hobbs, and many others have carried out notable observations 



