sigma-t surface occurred between 300 and 400 

 m., and the diagram depicting temperature on 

 this isentropic surface (fig. 23) suggests that 

 some total flow was occurring at these depths. 



Water Masses 



Water masses in the northern Baffin Bay 

 region have been defined on the basis of tem- 

 perature (Muench, 1971a) as: 



a. Baffin Bay Deep Water, extending from 

 about 1400 m. depth to the bottom of the basin, 

 characterized by temperature below 0° C. and 

 salinity of about 34.5%o. 



b. Baffin Bay Atlantic Water, extending from 

 100-300 m. depth down to the top of the Deep 

 Water layer, characterized by temperatures 

 above 0° C. and salinities between about 34.2 

 and 34.5%o. 



c. Baffin Bay Arctic Water extending from 

 the surface to the top of the Atlantic Water 

 layer, characterized by temperatures below 0° C. 

 (except near the surface, where higher tem- 

 peratures may occur locally due to warming 

 from above) , and salinity values from less than 

 31%o to about 34.4%o. 



Temperature-salinity (T-S) curves prepared 

 using the summer 1970 data were compiled and 

 their envelopes constructed (fig. 24a-d). The 

 envelope for northeastern Baffin Bay (fig. 24a) 

 indicates the presence of Baffin Bay Atlantic 

 and Arctic Waters. Baffin Bay Deep Water 

 occurs at greater depths than were sampled 

 and is not indicated on the envelopes. A wide 

 scatter in T-S values in the 0-50 m. layer rela- 

 tive to those values at greater depths was a 

 consequence of nonuniform summer warming 

 and melt water addition. 



The low temperatures above 100 m. depth and 

 low salinities relative to those at the same 

 depths farther south indicate that the water in 

 Smith Sound (fig. 24b) was of Arctic Ocean 

 origin. This agrees with the computed values 

 of net southward transport through Smith 

 Sound (Table I). 



Northwest Baffin Bay (fig. 24c) exhibited 

 a temperature-salinity structure similar to that 

 in northeastern Baffin Bay. Greater tempera- 

 ture variations at the temperature maximum in 

 northwest than in northeast Baffin Bay suggest 



an admixture of colder Arctic Ocean Water 

 into the water occurring in northwest Baffin 

 Bay. 



Lancaster Sound (fig. 24d) contained water 

 similar to that in Northwest Baflin Bay. Lower 

 temperatures above 100 m. in Lancaster Sound 

 than to the east reflect the net eastward flow 

 of colder water from the Arctic Ocean. 



The temperature-salinity properties show, as 

 during previous summers, a net inward flow 

 via Smith, Jones, and Lancaster Sounds leading 

 to a net southward flow through the system. 



SUMMARY AND CONCLUSIONS 



The summer 1970 oceanographic survey re- 

 vealed a relatively warm, saline lower layer 

 and a colder, less saline upper layer in north- 

 ern Baffin Bay. An inflow of Arctic Ocean 

 Water occurred through Smith, Jones, and Lan- 

 caster Sounds and fed a net southward flow 

 through the region. Mixture between south- 

 flowing Arctic Ocean Water from Smith Sound 

 and Baflin Bay Atlantic Water resulted in slight 

 attenuation of the temperature at the warm 

 core. Lowering of salinity within the Baffin Bay 

 Arctic Water in northwestern Baffin Bay was 

 due to an admixture of Arctic Ocean Water 

 from Lancaster Sound. 



The gross physical oceanography of the 

 northern Baffin Bay region in 1970 was similar 

 to that observed during previous summers. 

 Minor variations in the hydrographic structure 

 and circulation did not appear significant. 



REFERENCES 



Defant, A. (1961) Volume I of Physical Oceanography. 

 MacMillan Company, New York. Pp. 492-502. 



Muench, R. D. (1971a) The physical oceanography of 

 the northern Baffin Bay region. The Baffin Bay — 

 North Water Project Scientific Report No. 1, Jan- 

 uary 1971. Arctic Institute, Washington. 150 pp. 



Muench, R. D. (1971b) Oceanographic conditions in 

 Smith Sound and northern Baffin Bay, September 1968, 

 U. S. Coast Guard Oceanographic Report No. 37, 

 CG-373-37. 



Muench, R. D. (1971c) Oceanographic conditions in 

 the Melville Bay — Carey Islands region, northern 

 Baffin Bay, 17 September-2 October 1969, U. S. Coast 

 Guard Oceanographic Report No. 44, CG-373-44. 



