PHYSICAL OCEANOGRAPHY OF THE GULF OF MAINE 



727 



Changes in the salinity of the surface water off the western coast of Nova Scotia 

 from March to April, or to the southward of Cape Sable, demand attention, because 

 any considerable movement of the cold, comparatively fresh water of the Nova 

 Scotian current past Cape Sable from the eastward would necessarily decrease the 

 salinity of the neighboring parts of the Gulf of Maine, just as it retards the warming 

 of the surface there (p. 558). In 1920 no evidence of this appears in the distribution 

 of salinity up to the end of April. In fact, the surface was actually slightly Salter on 

 Browns Bank, near Seal Island, and off Yarmouth, Nova Scotia, on April 13 to 16 

 (stations 20102, 20104, and 20106) than it had been on March 13 to 23 (stations 20072, 

 20084, and 20085), and with no appreciable change in the Northern Channel.*" 



Stations 



300 



Fig. 103.— Salinity profile running eastward from Cape Cod, March 23 to 29, 1919 (ice patrol stations 1 to 3) 



In 1919, however, the very low temperature recorded in the eastern side of the 

 basin by the Ice Patrol cutter on March 29 (p. 553) had its counterpart in surface 

 sahnity considerably lower (31.87 per mills) than that of the western side of the gulf 

 at the time (32.4 to 32.7 per mille; fig. 103). Judging from the geographic location, 

 this can hardly have drawn from any source other than the Nova Scotian current. 



Unfortimately no observations were made on the salinity of the northern parts of 

 the gulf during the spring of 1919, so that it is impossible to state how much this 

 Nova Scotian water had affected the surface sahnity in that direction, nor (for the 

 same reason) how far it spread over the offshore banks to the southwest during 

 that spring. Probably, however, it reached its farthest westward expansion by the 

 last of that March or soon after, because a second profile of the gulf crossed the 

 isohaline for 32 per mille at about the same longitude a month later (Ice Patrol sta- 

 tions 19 to 22, p. 997) . A considerable amount of water of low salinity must therefore 



"No observations were taken in the gulf during the summer of 1920. 



