DAVIS STRAIT AND LABRADOR SEA 



63 



March 1935 of 7.5 million cubic meters per second when compared 

 with volumes found there in August 1935 and also durin<? several 

 other summers proves that tlie West Greenland Current is apparently 

 not seasonal, or. if seasonal, that effect is masked by greater varia- 

 tions noncyclic in character. 



The effects of winter chilling of the surface layers, and consequent 

 convectional mixing, are, however, plainly visible (fig. 36), where the 

 temperature and salinity gradients of May and September were com- 

 pletely erased by March. The sections JPurnish information on the 

 annual temperature range of the surface layers outside the shelf 

 off Cape Farewell. The temj^erature in the axis of the Irininger- 

 Atlantic current probably rises from a minimum in February of 

 about 4° C. to a maximum of slightly over 8° C. in Sej^teniber. 

 In the fresher water near the coast it probably ranges from —1.3° 

 C. at the end of winter to around 3.0° C. or 4.0° C. at the end of 

 summer. The May section of the Goclthaah apparently recorded a 

 point about midway of the annual cycle. 



The average temperature and the rate of heat transfer of the 

 West Greenland Current off Ca])e Farewell at the three seasons was 

 computed as follows : 



Annual thermal cycle of the West Greenland Current {Cape Fareicell) 



Date 



Volume of 

 flow 



Average 

 tempera- 

 ture 



Rate of 



heat 

 transfer 



Mar. 7-8, 1935.. 

 May 28-30, 1928 

 Sept. 2-3, 1928- 



7.5 

 4.0 

 3.2 



4.0 

 4. 1 

 4.4 



30.0 

 16.4 

 17.5 



Despite the Avinter chilling of the surface layers of the West Green- 

 land Current, the table shows that in some winters, at least, the cur- 

 rent transports more heat into the Labrador Sea than it does at 

 other times of a year. 



The higher average temperature of the deeper parts of the cur- 

 rent in March 1935 was also accompanied, according to the salinity 

 profile (fig. 36), by a correspondingly higher salinity. Warm, salty 

 water apparently mixed and sank to greater depths off Cape Fare- 

 well in March 1935 than in any of the summers for wdiicli there is 

 record. 



A more thorough internal mixing during winter below the fric- 

 tional influence of the wind may have been due to convectional cur- 

 rents, but an examination of the density profile reveals generally a 

 fair stability. The stability of any column in the section, 0-1,500 

 meters, w^as greatest closest to Cape Farewell and decreased directly 

 with the distance from the coast. Farthest out from the shore (3Ie- 

 teor^s station 120, fig. 36) the density was uniformly 27.75, surface 

 to 220 meters, but below^ there the density progressively increased 

 with depth to 27.88 at 1,500 meters. The maximum depth, there- 

 fore, to which convectional chilling was directly and actively pene- 

 trating around Cape Farewell March 7-8, 1935, was probably about 

 220 meters. Wintertime convectional currents are, however, believed 



