90 INTERNATIONAL ICE OBSERVATION AND ICE PATROL SERVICE. 



advance of summer. The minixnums of 1.6° C. and 0.4° C. at the 

 mtemiediate stations, 225 and 226, although high for polar water, 

 would lead one to suspect its presence, and salinities further support 

 such a contention. In any case, interdigitation of the slope water is 

 indicated. As for the cold bottom layer over the bank, that is un- 

 deniably of Arctic derivation. 



A comparison of Profile No. 10 with Profile No. 7 taken a month 

 earlier convinces one that the Labrador Current, which had curled 

 around the Tail and seeped in on the southern part of the bank 

 during April, had weakened and ceased to flow as far west of the Tail 

 as 51° 20' W. Since there is still well-defined Arctic water on the 

 bottom of the bank, this change was due to the Gulf Stream. There 

 is sufficient evidence to show that the latter has gro\vTi in strength 

 and is forcing its way northward, swamping the water which was 

 brought here during A})ril by the Labrador Current. This case 

 furnishes a good example of the continual variability in relative 

 strength and, consequently, in the relative positions, of these two 

 ocean currents. 



PROFILE NO. 11. STATIONS 201-211. 



This section runs from station ''C" (see chart ''A") westv/ard to 

 longitude 57° 10' W. It was occupied May 14-16. 



Salinity. — The feature of the section is the core of Atlantic water 

 at station 209, extending vertically from 100 meters to 330 meters. 

 From a glance at chart "A," it will be noted that station 209 Avas 

 somewhat south of the straight line connecting the other stations, and 

 this no doubt is the cause for cutting into Atlantic water. It also 

 indicates that the Gulf Stream is near, in longitude 53° 20' W. At 

 the 300-meter level, station 211, another northern extension of 

 Atlantic water is found. The relatively pariillel and horizontal posi- 

 tions of the isohalines indicate that this water west of the bank has 

 been quite free from interdigitation. Fresher water, 32.50 %o, lies 

 on the surface at the offshore station 211. Smce it is too fresh for 

 Labrador Current so far south, it may be an offshore movement of 

 coastal water. 



TemperaUfre. — A core of warm water >10° C. occupies the same 

 general position at station 209 as the 35.0 "/qq water in the salinity 

 profile. There is a bottom layer, 30 meters in thickness, of negative 

 temperature, on the bank. At the deep station, 211, a minimum 

 temperature of 0.0° C. is found at 50 meters. The low salinity and 

 low temperature leads to a conjecture that this water is from the 

 Gulf of St. LawTencc. 



Summary. — The. area west of the Great Bank is occupied, in the 

 main, by a large body of undisturbed slope water punctured by a 

 head of warm Atlantic water at station 209. At the westernmost 

 station, 211, the surface huors were fresher and colder; evidence 

 that Gulf of St. Lawrence water had projected seaward through the 

 Laurentian Channel. The low bottom temperature on the bank 

 is clear evidence of an admixture of water from the Labrador Current, 

 diluted, as proven by the low salinity, with the bank water which it 

 meets there. This was the most westerly trace of polar water at this 

 time. 



