PHYSICAL OOEANOGEAPHY OF THE GULP OP MAINE 



697 



Snowfall, in inches 



WINTEE, 1912-13 



1 Trace 



On the average, the coastwise belt of the gulf annually receives a blanket of 

 snow aggregating about 42 inches in thickness off Boston, 66 inches at Portland, 

 76 inches off Eastport, and 79 inches at Yarmouth, Nova Scotia. Translated 

 roughly into terms of ice, this means 4.5, 11, 8.5, and 9 inches, respectively, or an 

 equivalent of about 8 inches of ice as the mean for the coastwise belt from the 

 land out about to the 25-meter contour. Farther out from the shore a larger pro- 

 portion of the winter's precipitation comes down as rain, less as snow, but no meas- 

 urements of the snowfall have been made at any offshore station in the gulf. 



As to melt 1 kUogram of ordinary fresh-water ice requires heat enough to raise 

 the temperature of 75 to 80 kilograms of water by l",'** melting 8 inches of ice wUi 

 take heat enough from the water to cool a stratum 12 to 14 meters thick by about 1° ; 

 and probably this is a fair measure of the average cooling effect of snow falling on 

 the coastwise belt of the Gulf of Maine within 5 to 10 miles of the land. 



CHILLING EFFECT OF MELTING ICE 



The melting of floating ice in Mgh northern and high southern latitudes exerts a 

 potent effect upon the distribution of tem-perature " in the North Atlantic; and the 

 melting of ice, whether frozen locally or of Arctic origin (p. 689), is the most potent 



'« Recent measurements place the latent heat of fresh-water ice between 75 and 80.3 calories. (Eriimmel, 1907, p. 607.) 



" Salt-water ice is less effective as a cooling agent than fresh-water ice (floe ice, that is, than berg ice), because its latent heat of 



melting is somewhat lower. Petterson (1883) gives this as approximately 62 to 53 calories for ice frozen from water of about the 



salini ty of the Gulf Maine. 



