No complete explanation can be given at this 

 time. It is hoped that a similar cruise being under- 

 taken in 1966 will clarify the situation. 



Section A, well to the south and not shown on 

 figure 20, had a volume flow 1.28 X lO^mYsec and a 

 mean salinity 33.53%o. This section is sufficiently 

 far to the south of section B to peniiit lateral en- 

 trainment of the Labrador Sea water from the 

 east which not only reduces the amomit of the de- 

 fined water mass but also causes a salt and heat 

 increase. This would make these volume and salt 

 figures noncomparable with the values found in the 

 north. 



Smith (1937) did a limited amount of quanti- 

 tative work in the entrance to Hudson Strait based 

 on the 4 stations he obtained there. He estimated 

 the net discharge to be LOXlO^m^/sec, but points 

 up the probability of the seasonal and yearly 

 changes that occur. His calculations lacked data 

 in the strait north of Resolution Island. 



Quantitative flow work in Hudson Strait was 

 perfonued by both Campbell (1958) and Farqu- 

 harson and Sauer (1960). Campbell determined 

 the summer rate of the eastward current in Hud- 

 son Strait to be about 17 kilometers per day. Tlie 

 work done by Farquhai-son tends to support this 

 finding through the use of current meters. The 

 data from the 1965 expedition show a 49 kilometer 

 per day current flowing east through the entrance 

 across a 19-mile wide group of stations. Camp- 

 bell ( 1958) also made transport calculations of this 

 eastward flowing current within the strait. He 

 shows a net eastward flow of 0.3 X 10*'m'/sec. Cal- 

 culations based on the 1965 expedition indicates 

 a net eastward transport of 1.64X lO'^m^/sec, con- 

 siderably higher than found by Campbell (1958). 



The explanation of the discrepancies of the re- 

 sulting figures presented herein and those arrived 

 at by Campbell (1958) is found in the dift'erences 

 of location time, number of data points, and 

 method of dynamic calculations. Campbell's cal- 

 culations for July were made well within Hudson 

 Strait and not in the restrictive entrance which 

 would tend to increase the current velocities. His 

 volume flow values were arrived at for a location 

 west of Ungava Bay which undoubtedly con- 

 tributes a good deal of water to the net eastward 

 flow. The station location used by Campbell left 

 large gaps between the end of his sections and the 



coast. He speculates that as much of the flow 

 could be passing through this gap as passes 

 through the entire calculated section. Further- 

 more, his usage of a variable depth of no motion 

 within the strait limited by a maximum of about 

 350 meters, would not result in comparable com- 

 putations with those made using a 1000-meter 

 depth of no motion. In addition to the points 

 above, the difTerent years in which the data was 

 obtained could account for the incomparability 

 alone. 



FUTURE WORK 



Another expedition is planned during July and 

 August of 1966 to the Hudson Strait area. Survey 

 work will be performed both inside and outside 

 the entrance of the strait in an effort to tie the 

 circulation of both areas together. In addition, 

 parachute drogues will be used, during several 

 tidal cycles, in order to obtain direct measure- 

 ments of the net flow through the strait. Multiple 

 section occupations over several tidal cycles will 

 also be attempted in order to verify the constancy 

 of the distribution of mass regardless of the tidal 

 current fluctuation. 



SUMMARY 



The circulation of the Baffin Land Current is 

 into Hudson Strait, north and south of Resolution 

 Island. No large volume flow appears to be con- 

 tinuous between the Baffin Land Current and the 

 Labrador Current. To the east of Resolution Is- 

 land low velocity currents flow in a general south- 

 erly direction. The water flowing into Hudson 

 Strait has a mean salinity 0.64%^ higher than the 

 mean salinity of the water flowing out of the 

 strait. It is further indicated that the character- 

 istic low salinity water of the Labrador Current 

 emanates directly out of the strait and is the re- 

 sult of the mixing, within Hudson Strait, between 

 very low-salinity resident waters and the inflowing 

 Baffin Land Current. Calculations show that 

 1.64X lO^m^/sec outflow from Hudson Strait is 

 contributed to the Labrador Current. Calcula- 

 tions further show that this net outflow forms at 

 least 50 percent of the Labrador Current flowing 

 south of Hudson Strait. 



14 



