PHYSICAL OCEANOGRAPHY OP THE GULF OP MAINE 



SALINITY IN AUTUMN AND EARLY WINTER 



799 



Observations taken through September and October of 1915, in early November 

 of 1916, and at the end of that month in 1912 afford a general picture of the salinity 

 of the northern and western parts of the gulf at that season. Vachon (1918) and 

 Mavor (1923) also give autumnal data for 1916, 1917, and 1919 for various localities 

 in the Bay of Fundy region. 



In 1915 pairs of successive stations were occupied at intervals, expressly to show 

 the seasonal changes, if any; and when the salinities for these are plotted an increase 

 of 0.6 to 1.1 per mille is shown at the surface all along the coastwise belt east of Cape 

 Elizabeth from July and August to October — an increase of about 0.5 to 0.9 per 

 mille at the 50 to 60 meter level. At the same time, however, the vertical range of 



Fig. 160.— Vertical distribution o( salinity off QIoucBstor, August 31, 1915 (station 10308, dotted 

 curve), October 1, 1915 (A, station 10324), and October 31, 1916 (B, station 10399) 



salinity decreased somewhat off Mount Desert (fig. 107) and off Machias, a change 

 foreshadowing the vertical equaUzation of the water that takes place in winter (p. 801). 



A pair of stations for August 31 and October 1, 1915 (stations 10306 and 10324), 

 show a corresponding increase of nearly 1 per mille in the salinity of the upper 40 

 meters of water over the sink off Cape Ann at the mouth of Massachusetts Bay 

 (fig. 160), though very little change took place at depths greater than 50 meters 

 meantime, proving that the surrounding rim isolates its deeper strata of this bowl 

 effectively in autumn as it does earlier in the season. 



The superficial stratum off the mouth of Massachusetts Bay also seems to have 

 experienced some increase of salinity during the early autumn of 1916, the surface 

 value being about 0.5 per mille higher at the station in question (10399) on October 



