The density surfaces in the deep water are less regularly inclined in 

 the Greenland half and are not determinate in indicating the direc- 

 tion of flow. Because of the magnification of errors of measurement 

 in the integration over lai'ge vertical distances, the methods of dynamic 

 topogi-aphy cannot give us reliable answers here and, because of the 

 low velocities involved, the answer must await an extensive time series 

 of direct observations of the water movement. 



One feature of the oxygen disti'ibution (figures 25 and 26) which is 

 unexplained is the tongue of high values extending downward to a 

 depth of greater than 1,000 meters at stations 7943 and 7944. If this 

 were located somewhat to the southwestward it might represent water 

 least disturbed since wintertime convective jnixing. The salinities 

 and temperatures, however, indicate that it has been involved in the 

 restoration of sunnnertime conditions. 



Other difficulties with the foregoing hypotiu'sis of an annual inter- 

 mittant circulation cycle involve questions as to the rate of oxygen 

 consumption in tlic deeper levels, whether necessary horizontal and 

 vertical velocities are reasonable and whether the mechanism can 

 explain the occasional appearance, at levels of 2,500 to 3,000 meters, 

 of snudl quantities of water of salinity as high as 34.95 °/oo. A need 

 is indicated for a time series of observations to develop information 

 about the fall, wintci' and spring parts of the seasonal cycle. 



SUMMARY 



At the beginning of the 1961 season, there was probably an ab- 

 normal division of tiie Labrador Current into its eastern and western 

 branches with more than the usual proportion following the western 

 branch. Certainly the eastern branch was found to be subnormal, 

 especially south of the latitude of Flemish Cap. The surveys fol- 

 lowed the changes in this situation as conditions slowly returned to 

 normal near the end of the season. 



1. Five dynamic topographic charts resulting from the four sur- 

 veys made in the Grand Banks region during the season and tlu^ post- 

 season occupation of the Bonavista triangle have been presented. 



2. The temperature-salinity characteristics of the three water 

 masses found in the (Jrand Baid-cs region during the 1961 season have 

 been compared with the means foi- the 14-year period 1948-61. 



3. The volume and heat transports and nu'an and minimum ob- 

 served temperatures h)un(l (hu'iiig 23 occupations of sections across 

 the Ijabrador (\u"rent in 1961 have been pi'csentfMl in comparison 

 with tentative seasonal normals. 



4. The circulation in the inteniuMhate, (h'ep and bottom water of 

 the l^abrador Sea has been discussed in the hght of the tem])erature, 

 salinity and oxygen distribution found in 1961 along the section from 

 South Wolf Island, Labrador to Cape F'arc^well, Gre(Mil:ind. 



42 



