•»•!"' 15' N, 67°58 W COASTAL MAINE 

 44-00' N. 67°16'W CENTRAL GULF 



43"47'N 66"30'W COASTAL NOVA SCOTIA 



Figure 13.— Sea bottom temperature (°C) at three locations (Fig. 1) across Ihc Culf of .Maine, .June l!)7.i-November 197ft. 1976 Summer and 



Autumn data indicated by "7f>". 



VI sn SID 



JUN I JUL I AUG 



'igure 14. — Sea surface salinity (7,= ) at three locations (Fig. I) across the Gulf of Maine, June 197.5-November 1976. 1976 Summer and Au- 

 tumn data indicated by "76", 



Central Middepth Waters 



The cooler middepth temperatures found in spring and 

 early summer 1976, summer 1975, and historical spring 

 and summer sections, appear to be formed from winter- 

 cooled water constricted by the offshore progression of 

 warmer coastal waters, the development of the surface 

 thermodine, and the persistence of warmer central bot- 

 tom waters (>150 m). This layer warmed during summer 

 197.5, and dissipated by August of that year. Warming 

 continued at middepth through October as surface- 

 warmed waters mixed downward. A change from warm- 

 ing to cooling occurred in November with homogeneous 

 conditions developing. This cooling trend accelerated 

 through the winter months, with mininuim tempera- 



tures occurring during March 1976. As the surface and 

 coastal warming trends began, the minimum tempera- 

 ture laver developed its spring characteristics, with slow 

 warming (l°r per month) into early summer and dis- 

 sipation by July. The occurrence of this layer in both 

 years and in historical data indicates that it is a charac- 

 teristic part of the spring temperature structure. 



Central Bottom Waters 



Waters deeper than l.'iO m maintained a slow rise 

 (<I°r per month) in temperature, with no seasonal pat- 

 tern of warming or cooling evident from the data. A lack 

 of seasonal trends was also evident in historical sections. 



