In bulletin number 42 of this series average temperatures were plotted 

 against average salinities for the intermediate water and for the deep 

 water at 2,000, 2,500, 3,000 and 3,500 meters for each occupation of 

 this section. For purposes of comparison similar values for the 1957 

 occupation of the section are given below : 



Thus the intermediate water was near the cold limit of the group of 

 occupations 1934-41 and 1948-57 and the salinity was lower than any- 

 other year of the group. In the deep water both temperature and 

 salinity were close to these values for the 1953 occupation at 2,000, 2,500 

 and 3,000 meters and near the cold and low salinity limits of the group 

 at 3,500 meters. The values of <x t corresponding to these average 

 temperatures and average salinities were smaller than found in 1956 at 

 all levels. This continues the trend of the last two decades toward 

 lighter water. 



SUMMARY 



1. The two dynamic topographic charts resulting from the season's 

 current surveys and the dynamic topography found at the Bonavista 

 triangle during the postseason cruise have been discussed with respect 

 to surface circulation. 



2. Temperature-salinity relationships of the Labrador Current water, 

 Atlantic Current water and mixed water, found in the Grand Banks 

 region during 1957, have been compared with mean T-S curves for the 

 period 1948-57. The continuation of the trend of the last few years 

 to increasing salinity in the upper 200 meters in the Labrador Current 

 and freshening of the water below that level has been noted. 



3. Year to year changes in density of the Labrador Current water 

 have been noted for the periods 1934-41 and 1948-57. 



4. The apparent relation between the position of the cold wall in the 

 Grand Banks sector and sea level differences at Bermuda and Charleston 

 were further investigated in the light of more recent data, and it was 

 concluded that the correlation found in prewar years was fortuitous. 



5. A more detailed analysis of the circulation in the upper 1,000 meters 

 has been made on the basis of volume and heat transports and mean and 

 minimum observed temperatures at 12 selected sections across the 

 Labrador Current occupied during the 1957 season and postseason 

 surveys. 



6. The exceptionally vigorous circulation on both the Labrador and 

 Greenland sides of the Labrador Sea in 1957 has been noted. 



103 



