PHYSICAL OCEANOGRAPHY OF THE GULF OF MAINE 655 



of Gloucester in 1913, for the southern side of the Massachusetts Bay region in 1925 

 and for the Bay of Fundy region show that the water continues to cool during these 

 months. In 1924-25 cold weather at about Christmas was reflected in the southern 

 half of Massachusetts Bay by temperatures about 2.5° lower on January 6 and 7 

 than they had been on December 22 and 23, the mean temperature having fallen to 

 about 2.5° to 2.6°, surface to bottom.^" 



Large amounts of ice formed in the southeastern side of Cape Cod Bay during 

 the low temperatures and northwest gales of the last week of that December, until 

 it was packed several feet high on the flats and along the beaches south of Wellfleet, 

 reaching for a mile or more offshore as I saw it on the 29th. Its chilling effect is 

 reflected in the fact that the temperature of the water was much lower (0.3° on the 

 surface, 0.25° on bottom in 13 meters) off Billingsgate Shoal on January 7 {Fish 

 Hawk cruise 5, station 7) than at the other stations for that cruise. 



The surface temperatures for this January cruise (fig. 81) are also instructive as 

 an illustration of the gradation from lowest readings of 0.5 ° to 2.5 °, close in to the 

 shore, to warmer water (4° to 5°) in the center of the bay, characteristic of the 

 season. A reading of 2.78° a mile off the mouth of Gloucester Harbor on this same 

 date shows that the coldest band was continuous right around the coast line of the 

 bay, as it had been the month before (p. 650). 



Probably the mouth of the bay, generally, and the open basin in its offing are 

 usually about 5° to 5.5° in temperature at the second week of January at all depths, 

 judging from readings of 5.3° to '5.6°, surface to bottom, in 70 meters off Gloucester 

 on the 16th of the month in 1913 (station 10050). 



On January 6 and 7, 1925, the surface (fig. 81) was slightly cooler than the bot- 

 tom at the four stations in the central part of Massachusetts Bay {Fish Eawk cruise 

 5, stations 19, 18, 2, and 4) and in the eastern side of Cape Cod Bay (station 6), 

 fractionally warmer than the bottom in the southern part of the latter and along the 

 Plymouth shore. Nor is the cause for this slight regional difference clear, for most of 

 the stations of the second group, as well as of the first, were occupied on the ebb tide. 



On January 9, 1920, Gloucester Harbor was between 0° and 1° (fig. 29), Booth- 

 bay Harbor fractionally colder than 0° (fig. 30), and Lubec Narrows about 0° (fig. 

 31), showing that the temperature falls about equally fast in such situations all 

 around the western and northern shores of the gulf in spite of the difference in lati- 

 tude." The water is also about as cold at Woods Hole at this season (Sumner, 

 Osburn, and Cole, 1913; Fish, 1925). 



Massachusetts Bay is coldest during the first half of February; and this prob- 

 ably applies to the gulf as a whole. The precise date when the temperature fell to 

 its minimum can not be stated for any of the years of record (no doubt this varies 

 from year to year, as well as regionally), but the readings taken in the bay on 

 February 6 and 7, 1925 {Fish Hawk cruise 6), were close to the coldest for that 

 particular winter. 



On this date the surface of the southern side of the bay (mean temperature 

 about 0.75°) averaged about 2° colder than it had on January 6 and 7, though the 

 regional distribution of temperature (fig. 82) continued reminiscent of the late December 



^iThe mean tomporature of the air had been below normal at Boston oo every day save three since Dec. 19. 

 "Gloucester Harbor, 42° 35' N; Lubec Narrows, W 49' N. 



