interpreting the higher volume at section U as being the result 

 of recirculation of mixed water from the eastward. The marked 

 increase in mean temperature at section W indicates the presence 

 of a considerable proportion of recirculating mixed water. 



Except for noting the increase in transport at the Bonavista 

 triangle during the post-season cruise over that found during the 

 second survey, and the higher than average transport (both vol- 

 ume and heat) and mean temperature at the South Wolf Island 

 section, discussion of the circulation found during the post-season 

 cruise will be deferred until after the data on the complete South 

 Wolf-Cape Farewell section have been presented. 



The temperature-salinity relationships found in the past in the 

 Grand Banks region at levels below 75 meters have established the 

 Labrador Current water and the Atlantic Current water as water 

 masses, and usually the mixed water derived from these water 

 masses has been sufficiently uniform to permit it to be considered 

 as a virtual water mass. The T-S curves for individual stations 

 occupied during the first and third surveys have been examined 

 and classified as Labrador Current water, mixed water, or Atlantic 

 Current water. During the first survey a small group of stations 

 classified as mixed water followed a consistent pattern similar to 

 the characteristic mixed water found in the past. The remaining 

 mixed water stations, however, had T-S curves which varied from 

 normal mixed water to nearly Atlantic Current water, indicating 

 the presence of water mixed from the parent water masses in vary- 

 ing proportions. The stations at which the abnormal mixed water 

 was found formed a belt bordering the Atlantic Current water and 

 extended to the edge of the Grand Banks on its southwestern 

 slope. The area containing stations at which the usual mixed 

 water was found extended from the Tail of the Banks to Flemish 

 Cap as a zone between the abnormal mixed water and the Lab- 

 rador Current water. During the third sui'vey no such belt of 

 abnormal mixed water was found.^ 



In figure 11 the T-S relationships found during 1951 have been 

 shown for each of the three water masses in comparison with 

 similar T-S curves representing the mean of conditions found 

 during the 8-year period 1934-41. In drawing the curve for 



* Since individual station curves are not identical, a check was made to determine whether 

 or not the mixed water was a virtual water mass and not mei'ely an apparent water mass 

 derived from the bias of earlier work. The probable departures of temperature and salinity, 

 at a given level at an individual station, from temperature and salinity at that level on the 

 mean curves shown in figure 11 were computed for each level for each mean curve for 1951. 

 These probable differences were then used as the axes of elipses constructed with their centers 

 at the appropriate level on the mean curve. While the elipse patterns overlapped, each mean 

 curve fell outside the envelopes of the elipses of the other two curves. Taken level for level 

 the elipses of the three curves did not overlap except at 600 meters and below for mixed water 

 and Labrador Current water, and at 1,500 meters for mixed water and Atlantic Current water. 

 It was concluded that in 1951 the mixed water was a virtual water mass. 



30 



