section by about 0.8, which represents the contributions through 

 the northern openings less such an amount as sank below the 

 reference surface of 1,500 decibars. 



SUMMARY 



1. The surface circulation in the Grand Banks region in 1951 

 has been discussed on the basis of three dynamic topographic 

 charts made during the season. 



2. A more detailed picture of the circulation in the upper 1,000 

 meters in the Grand Banks region has been presented on the basis 

 of volume of flow, mean temperature, and minimum observed tem- 

 perature of the Labrador Current at 14 occupations of 8 selected 

 sections made during the 1951 season. 



3. The temperature-salinity relationships for the three water 

 masses found in the Grand Banks region in 1951 have been com- 

 pared with conditions found in other years. 



4. Observations made with a von Arx geomagnetic electro- 

 kinetograph in 1950 and 1951 have been given further study in 

 comparison with the dynamic topography based on concurrently 

 collected temperature and salinity observations. A method of 

 applying the stream function to the construction of a contoured 

 current chart from the GEK vectors has been described and four 

 charts made by its use have been presented. 



5. The relationship between the location of the northern boun- 

 dary of North Atlantic Current water in the Grand Banks region, 

 the strength of the Labrador Current, and the changes in the dif- 

 ference in sea-level between Bermuda and Charleston have been 

 reviewed in the light of 27 surveys made during the period 1934-41 

 and 8 surveys made 1948-51. A weakened post-war circulation in 

 the North Atlantic eddy, deduced from changes in the sea level dif- 

 ference at the Bermuda-Charleston section, has been proposed as 

 a possible explanation for the deficiency of the Irminger Current 

 component of the West Greenland Current at Cape Farewell. 



6. An increase in temperature of the intermediate water of the 

 Labrador Sea in 1951 over 1950 has been noted and the thermal 

 characteristics of the section from South Wolf Island, Labrador, to 

 Cape Farewell, Greenland, have been compared with those found 

 in earlier occupations of this section. 



7. The circulation in the southern part of the Labrador Sea has 

 been inferred from examination of the volume transport and mean 

 temperature of the Labrador Current and West Greenland Current 

 and, with the supporting evidence of temperature and salinity 

 observations, it has been concluded that the Irminger Current com- 

 ponent of the West Greenland Current continued to be deficient in 

 1951. 



53 



