compared. In exploring the concept of a 

 freshet, attention must be given not only to 

 the possibility of water from melting snow 

 and ice being a component of the Labrador 

 Current transport, but also to the possible ac- 

 celerating effect of meltwater accumulated 

 along the Labrador and Newfoundland coasts. 



That meltwater from snow and ice along 

 the Labrador and Newfoundland coasts is a 

 significant component of the total transport 

 of the Labrador Current appears unlikely. The 

 strongly negative temperatures and substantial 

 volume of the cold current observed on the 

 eastern slopes of the Grand Banks testify to a 

 high-latitude origin, and the greater velocities 

 in the Labrador Current actually occur to the 

 east of the cold core in waters that are warmer 

 and more saline. 



Remaining to be examined is the possibility 

 of accumulated meltwater along the Labrador 

 and Newfoundland coasts providing a hori- 

 zontal pressure gradient suflficient to accelerate 

 the Labrador Current. This hypothesis has 

 been treated favorably by previous investiga- 

 tors of this i-egion. Kollmeyer et al. (1966) 

 stated that an increase in dynamic height on 

 the Grand Banks "could be caused by the influx 

 of arctic and sub-arctic melt water [sic] from 

 the north" and that "the increase in elevation 

 of water on the Banks and slope, with a re- 

 sulting water volume flow increase, causes en- 

 trainment of the existing water in the area. 

 This slope water would then become colder 

 with the arrival from the north of greater 

 volumes of cold water to fulfill the mass 

 continuity requirements being satisfied by 

 entrainment." 



Along Section A3 west of the trough, the 

 dramatic increase in surface dynamic height 

 between the surveys of 18 and 24-25 May 1968 

 and its abrupt decline between the surveys of 

 20 and 26 June 1968 were compared with 

 variation in the temperature-salinity charac- 

 teristics of the adjacent station. These compari- 

 sons indicated that during 1968 the greatest 

 variation in the volume flow of the Labra- 

 dor Current was accompanied by variation in 

 salinity below 200 meters at the adjacent sta- 

 tion. The increase in dynamic height between 

 the 18 May and 24 May occupations of the 

 adjacent stations (stations 190 and 224) oc- 

 curred even though the water in the depth 

 interval of to 200 meters was denser during 



the 24 May occupation (fig. 40) as a result of 

 an increase in salinity. Thus, during the 1968 

 Ice Patrol season, the greatest difference in 

 dynamic height between the trough station and 

 the station immediately west of the trough oc- 

 curred while the waters of the upper 200 

 meters of the adjacent station were becoming 

 more saline — hardly conditions to be associated 

 with an influx of meltwater in the surface 

 layers of the Grand Banks. Instead, an influx 

 of fresher, warmer, and less dense water below 

 200 meters was responsible for the increase 

 in dynamic height. 



The abrupt decrease in the dynamic height 

 of the station immediately west of the trough 

 between the 20 June (station 271) and 26 

 June (station 315) occupations was due to the 

 presence of denser water at station 315 at all 

 levels (fig. 41). Except at the sea surface, this 

 increase in density was caused by an increase 

 in salinity. The surface salinity at station 271 

 differs only slightly (0.08°/oo ) from the salin- 

 ity of colder water (-1.04°C) at 30 meters, 

 suggesting that the surface water may be water 

 of nearly the same origin as the relatively 

 fresh, negative temperature water between 20 

 and 90 meters. 



A plot of the volume transport of the cold 

 core (<2°C, <34°/oo of the Labrador Cur- 

 rent and of the total Labrador Current for 

 Section A3 and the east-west leg of Section A2 

 (fig. 43) indicates that the fluctuations in 

 transport on both sections are in good agree- 

 ment. Because the magnitude of the fluctua- 

 tions in the total transport of the Labrador 

 Current exceeds the magnitude of the fluctua- 

 tions in the cold-core transport, variation in 

 the total flow of the Labrador Current along 

 the eastern slope of the Grand Banks does not 

 appear to be due solely to variation in the ad- 

 vection of water from more northern latitudes. 



The causes of the sudden increase in the 

 total transport of the Labrador Current in May 

 and its abrupt decrease in late June may now 

 be speculated upon. During May an influx of 

 fresher, warmer water below 200 meters at 

 station 224 was responsible for a sharp in- 

 crease (fig. 37) in the gradient of dynamic 

 height between the trough station and the ad- 

 jacent station, deepening the Labrador Current 

 and increasing the transport of the cold core 

 (fig. 43). The increase in dynamic height of 

 the adjacent station was then sustained by a 



