Oceanography of the Grand Banks Region 

 and the Labrador Sea in 1966 



by 

 Thomas C. Wolford, U.S. Coast Guard Oceanographic Unit 



INTRODUCTION 



The 1966 International Ice Patrol oceano- 

 graphic program differed from those of the 

 preceding seasons in several respects. The 

 number of sections occupied was reduced to 

 three to speed up coverage and to increase the 

 synoptic value of the data. Time series observa- 

 tions were also made along one section to study 

 fluctuations in the Labrador Current. Opera- 

 tional tests were conducted on the Bissett- 

 Berman 9006-N Salinity/Temperature/Depth 

 Measuring System (STD) and on a very low 

 frequency radio navigation system. Processed 

 oceanographic data was transmitted routinely 

 to the National Oceanographic Data Center, 

 Commander International Ice Patrol, Navy 

 Fleet Numerical Weather Facility, and the 

 Naval Oceanographic Office. 



The three survey sections. Sections 2, 3, and 

 4 shown in Figure 1, were chosen to delineate 

 important features of the juncture of the 

 Labrador-North Atlantic Current systems and 

 to permit comparison of the data with histori- 

 cal Ice Patrol data. They were used to provide 

 calibration factors to the mean dynamic topog- 

 raphy charts prepared by Soule (1964). They 

 were used to locate the axis of the Labrador 

 Current, the position of the trough between 

 the Labrador and North Atlantic Currents, 

 and to determine the amount, if any, of east- 

 ward branching of the Labrador Current north 

 of Flemish Cap. 



Hydrographic data obtained during mid- 

 February and during March by Ocean Station 

 Vessels were also processed. This data, the 

 earliest ever collected, indicated the late-winter 

 characteristics of the Labrador Current. 



NARRATIVE 



General 



Two distinct oceanographic cruises were 

 conducted during the spring of 1966. The first 



cruise provided operational support for Com- 

 mander, International Ice Patrol and the sec- 

 ond cruise collected data to document the 

 anomalous conditions encountered during the 

 first cruise. Both oceanographic cruises were 

 conducted by the CGC EVERGREEN, a 180- 

 foot tender class oceanographic vessel. 



The first cruise began on 2 April 1966 with 

 the occupation of EVERGREEN station 9509 

 on the north-south Standard Section 4 at the 

 "Tail-of-the-Banks" and proceeded northward 

 with serial stations terminating at station 9534 

 on the Gi'and Banks west of Flemish Cap on 

 8 April 1966. See Figure 1 for the dynamic 

 topography of the sea surface and the station 

 locations for this survey. The synopticity of 

 this survey was reduced because of the severe 

 weather encountered during the cruise. The 

 vertical temperature distribution and the dy- 

 namic height at each station were provided 

 to Commander, International Ice Patrol within 

 twelve hours of observation. The survey was 

 terminated on 11 April 1966 when repeated 

 attempts to accurately determine the ship's 

 position failed prior to a planned reoccupation 

 of Standard Section 3. 



During the second part of the first cruise, 

 which lasted from 15 to 25 April 1966, CGC 

 EVERGREEN occupied serial stations 9535 to 

 9551. See Figures 2A, 2B, and 2C for the dy- 

 namic topography of the sea surface and the 

 station locations for these occupations. These 

 stations were part of a time series study to 

 determine the volume transport variations of 

 the Labrador Current along a 25 mile length 

 of the western part of Standard Section 3. 

 This section was occupied three times during a 

 five day period. A moored toroidal buoy was 

 used as a reference to insure that each station 

 of the three successive occupations was at the 

 same location. After the first occupation of the 

 section, parachute drogues were used to verify 



