96 INTERNATIONAL ICE OBSERVATION AND ICE PATROL SERVICE. 



of the year, but upon the slopes and across the southern end the 

 polar water is subject to variations. There is a well-defined tendency 

 on the part of the polar water, when spreading in over the southern 

 end of the bank, to seek the bottom levels. Attention is called to 

 the position of the Labrador Current in relation to the Great Bank. 

 The subsurface observations for 1922 show no evidence of a general 

 southwesterly set of Labrador Current across the Great Bank in the 

 form of a definite stream. 



The freshest water found during 1922 was the upper layers over the 

 bank, which often are of such low salinity that the water is classified 

 as coastal, for in order that water be so fresh it must have coastal 

 connection. Land drainage spreads superficially out over the Great 

 Bank in a slow offshore expansion which is accelerated or retarded 

 by the tides, winds, etc., but is sufficiently constant to maintain the 

 low salinity so permanently a characteristic of the bank area. 



Average annual conditions from year to year produce a remarkable 

 constant state of the water over the Great Bank. The encroachments 

 of the Labrador Current on the Gulf Stream in over the bank are to 

 be regarded as abnormalities. Sucli temporary conditions of oceanic 

 circulation can be traced to an accumulation of water seeking escape 

 in distinction to the stream flow of an ocean current w^hicii tends 

 quite consistently to the steepest grade of a continental slope. 



Another noticeable and interesting feature was the action of the 

 slope waters during the 1922 season. This consisted of a combina- 

 tion of bank and polar water, which exhibited a marked tendency 

 to spread out to the southw^ard of the Tail on the surface, abutting 

 into the northern edge of the Gulf Stream. There may be several 

 causes for this offshore expansion, such as an escape from the inshore 

 accumulation of coastal water draining off the slopes; it may be the 

 result of a pull from a surface suction induced by an increased density 

 at the juncture of the Gulf Stream and the Labrador Current. The 

 phenomenon with which we are interested, however, is the fact that 

 the slope water (Labrador Current plus bank water) spreads out 

 superficially, as shown by all the profiles, and does not sink. This is 

 convincing proof that the Labrador Current, upon meeting the Gulf 

 Stream south of the Grand Banks of Newfoundland, does not dive 

 beneath the latter to emerge farther south. Ocean currents may 

 e.xhibit such action at other places in the world, but such certainly 

 is not the case at the Tail of the Great Bank. 



If tlie Labrador Current does not dive beneath the Gulf Stream, 

 what becomes of it? Floating objects furnish us with the most 

 direct information as to the velocity, direction, ami limits of a cur- 

 rent. Icebergs, because of their size and drjft, record a drift which 

 represents the average movement of the body of water as a whole, 

 since the wind seldom influences them. The reatler is referred to 

 tracks of the drifts of bergs south of the Tail of the Great Bank for 

 1922. With the bergs as indicators, it will be seen from charts 

 "D," '^F," ''G," that the Lalmidor Current flows around the Tail 

 and southwesterly to about 42° 22' N., 51° 28' W. (and as modified 

 by page 95), where it is turned sliarply, with varying etldy formations, 

 in a return flow parallel to the Gulf Stream. 



Conclusions drawn: 1. The Labrador Current is weak during the 

 winter months, when its southern extension lies near the northern 

 part of the Grand Banks of Ne^^'foundland. 



