N antucket 3h£al_s, Texas_ Twer_n (Figure 6, Table 6) 



The observations at Texas Tower ""AS, Nantucl;et Shoals, which began in 

 March afford an interesting comparison V7ita the record from Texas Tower -l^l 

 at Georges Shoal. From i:arch through mid-July the records run parallel, 

 with Nantucket Shoals temperatures running slightly below those at Georges 

 Shoals. From the end of July througli December, however, surface vjater 

 temperatures at Nantucket Shoals lagged behind those at Georges Shoals by 

 more than 5 F. Bigelow (1927, pp. 594-595) remarJcs on the comparatively 

 cool water found in August over the shallow broken bottom south of Nantucket 

 and says that probably "this cold area is separated from the equally lov.' 

 surface temperatures of Georges Bank by a band of warm surface v/ater along 

 the so-called 'south channel',.. ' SuDsequent surveys (unpublished data in 

 files of Woods Hole Oceanographic Institution) show that these two cool 

 areas are separated, but by a region of even colder water in South Channel 

 in July, August and September. It seems likely, then, that the low 

 temperatures found at Nantucket Shoals represent the western margin of an 

 area of upwelling, and that the southwesterly wind regime which characterizes 

 the summer months in the region drive the warmed surface water to the 

 northeast along the northern edge of Georges Bank, allowing replacement by 

 deep water from the Gulf of Maine. This is in agreement with drift-bottle 

 studies (Day, 1959) which show that southvjesterly winds give an onshore 

 component of movement of surface water south of Nantucket and an accelerated 

 northeasterly movement along the northern edge of Georges Bank.. 



AUG SEP 



Figure b. Nantucket Shoals, Texas Tower #3, 1958. 



29 



