ABSTRACT 



The authority for, mission, forces assigned and method of operation 

 of the International Ice Patrol during the 1955 ice season are de- 

 scribed. 



Statistics are presented in connection with the aerial ice observation 

 and communications conducted by the International Ice Patrol in 

 1955. 



Ice reports received by the International Ice Patrol during the year 

 are tabulated. A general description of ice conditions in the New- 

 foundland area is given. Only 61 bergs drifted south of the 48th 

 parallel during 1955, as compared with the 1900-1955 average, 396 

 bergs. The distribution of these bergs was abnormal. No bergs 

 were found along the east slope of the Grand Banks or in the Flemish 

 Cap area. The duration of the pack ice in the Grand Banks area 

 was about normal, but the extent of the pack to the south and east 

 of the Newfoundland coast was subnormal. Except for the Strait 

 of Belle Isle, all routes to ports in the Gulf of St. Lawrence and St. 

 Lawrence River were clear by 16 April. The strait of Belle Isle route 

 was navigable by 12 June. 



The oceanographic vessel of the patrol made three dynamic topo- 

 graphic surve^^s during the season and collected additional data during 

 a post-season cruise. Because of the distribution of the ice only the 

 first of the season's survey's extended south of the latitude of Flemish 

 Cap. On the post-season cruise the Bonavista triangle and the South 

 Wolf Island-Cape Farewell section were occupied. 



The surface circulation has been discussed in the light of the dynamic 

 topographic cliarts, and a more detailed examination of the circulation 

 in the upper 1 ,000 meters in the vicinity of the Labrador Current has 

 been based on the volume transport, mean temperature, heat trans- 

 port and minimum observed temperature found during 17 occupations 

 of 11 selected sections across that current. Temperature-salinity 

 relationships of the water masses in the Grand Banks region, the 

 relationship between the position of the cold wall and the relative 

 strengths of the adjacent current systems, and the temperature, 

 salinity and total phosphorus conditions found in 1955 have been 

 compared with conditions found in earlier years to the limited extent 

 permitted by the smaller volume of data collected in 1955. 



(v) 



