the slightly higher salinity water running in. The 

 T-S diagrams of section D abruptly shift toward 

 the lower salinity values and lower temperatures 

 ,d station 9454. 



Section C, west of station 9437, exhibits water 

 characteristics much less saline, but not quite as 

 cold as the waters to the north in section G. Lo- 

 cal warming, and some mixing of water from the 

 east, can account for the elevation in temperatures, 

 however, no water from the north or east can con- 

 tribute the low salinity values found in section C. 

 Section D does not contain these low values of 

 salinity either, but they are found in section D'. 

 This section, just to the west of Cape Ohidley, 

 seems to be the source of the low salinity waters 

 of section C even though no good continuity of low 

 salinity water can be shown to connect them. As 

 discussed in a previous section, tidal fluctuations, 

 mixing and improper timing of the survey ship 

 in transiting section D probably accounts for the 

 lack of continuity of the water masses. 



Section B, to the south, shows low salinity and 

 slightly warmer water. Warming would be ex- 

 pected here as the colder water passed south into 

 shallower shelf areas. 



The circulation concepts postulated from the 

 dynamic height and the isentropic charts appear 

 to be borne out by tracing the flow patterns using 

 T-S relationships. 



TEMPERATURE TIME STUDY 



Presented in figure 18 is a time-series study of 

 the temperature structure of the water in the en- 

 trance to Hudson Strait. The location was in the 

 vicinity of station number 945'2, about 8 miles north 

 of the islands off Cape Chidley. An attempt was 

 made to observe the cold, low salinity water, mov- 

 ing eastward out of the strait from its source 

 southwest of Cape Chidley. ITnfortunately this 

 area turned out to be an area of low geostrophic 

 current. Radar was used to keep the ship's posi- 

 tion fixed and drift plots of the vessels were used 

 to determine the tidal current changes. Figure 

 18 shows the electronic bathythermograph 

 (ELBT) records obtained in this location along 

 with ELBT records obtained both inside the 

 strait, station 9461, section D' and outside the 

 strait, stations 9444, 9443, section C. Station 9461 

 is located within the cold, low salinity water mass 

 believed to be the source of the characteristic 

 Labrador Current. 



The arrival of the colder water, at least as cold 

 as found in quantity in section C, stations 9443 

 and 9444, can be seen in figure 18. This arrival 

 appears nicely timed with the end of the observed 

 ebb current. The temperature structure shows the 

 increase and decrease in the amount of cold water 

 moving through the strait to be obviously con- 

 nected with the tidal current as hypothesized 

 previously. The failure to obtain a Nansen cast at 

 the time of the arrival of this cold water prevents 

 the proof of lowered salinity of this water, how- 

 ever, from the other evidences presented this is a 

 logical assumption. 



MEAN SALINITY DISTRIBUTIONS 



One of the more revealing analyzations of the 

 data is presented in figure 19. Show^l here is the 

 mean salinity of the southward moving water 

 within the defined characteristics of less than 2° C. 

 and 34.3%o. These mean salinities were obtained 

 by using the values of the salt transport and the 

 volume flow in the following equation : 



S»/oo = 



Ms 

 Vp 



where : 



M5=salt transport 

 V= volume flow 

 p= density of sea water 



The mean salinities of the water exchanged 

 through the entrance of Hudson Strait were com- 

 puted for both directions of flow because of the 

 large changes in the salt concentration and flow 

 patterns across the entrance. 



The northernmost section of figure 19, section 

 G, shows a 33.37%o mean salinity for the south- 

 ward flowing Baffin Land Current. Further to 

 the south, this current appears to shed a lower 

 salinity filament which flows into Hudson Strait, 

 north of Resolution Island through section E. 

 The source of this lower salinity filament is the 

 inshore or coastal portion of the Baffin Land Cur- 

 rent. The salinity of the section extending east of 

 Resolution Island, section F, is higher than the 

 Baffin Land Current in section G to the north. 

 This increase in salinity is the result of both the 

 loss of the inshore filament flowing through sec- 

 tion E, and the intrusion of more saline water 

 from the western Labrador Sea. 



Directly to the south of section F, section C ex- 

 hibits a mean salinity considerably lower than any 



11 



