depth for the three occupations of section A3 

 from 21 May to 2 June (fig. 28). During the 

 final occupation of A3 during 1-2 June, the 

 total transport between stations 577 and 576 

 (0.83x10'' mVsec) was less than the total 

 transport between the corresponding stations, 

 506 and 505 ( 1.31 X 10"^ mVsec), during the 

 21-22 May occupation of A3, even though the 

 gradient in surface dynamic height was greater 

 between stations 577 and 576 than between sta- 

 tions 506 and 505 (fig. 28). This apparently 

 anomalous result is the consequence of the 

 gradient of surface dynamic height between 

 stations 577 and 576 primarily depending on 

 the characteristics of the water column above 

 250 meters. 



Profiles of density (o-,) for the three occupa- 

 tions of A3 from 21 May to 2 June (figs. 29, 

 30, and 31) show an increase in density at the 

 trough stations, which was associated with the 

 decrease in dynamic height observed during 

 this period. During the 28-29 May survey, 

 when the observed transport of the total Lab- 

 rador Current was at a maximum, water den- 

 sities observed below the 400 meter level along 

 the slope of the banks were less than during 

 the preceding and succeeding occupations. These 

 changes in density were due primarily to 

 changes in salinity. During the period 20 May 

 to 2 June, the salinity of the water column 

 below 30 m at the trough station increased 

 (figs. 19, 23, and 25), while at the adjacent 

 station the salinity reached a minimum during 

 the 28-29 May occupation of A3. 



Labrador Sea Section 



Oceanographic conditions along the Labrador 

 Sea section from South Wolf Island, Labrador, 

 to Cape Farewell, Greenland, occupied by CGC 

 SHERMAN from 15 to 19 August 19G9 (figs. 

 32 and 33) were similar to those observed on 

 previous occupations. Southward flowing Lab- 

 rador Current Water was present in two 

 branches (fig. 34); a shelf band (<1.0°C, 

 <34.4°/^^) between stations 110 and 108, and 

 a slope band (>0°C, >34.0°/,,J between sta- 

 tions 88 and 91. At the Greenland side of this 

 section, the northward flowing West Greenland 

 Current was found between stations 100 and 

 104. However, the cold (<1°C) East Greenland 



Current component was found only at station 

 104; sea ice prevented the occupation of any 

 stations nearer to shore. 



The surface temperatures during the October 

 WE ST WIND occupation were cooler by 4 to 

 6C° than the August occupation, but the 

 temperatures over the Labrador and Greenland 

 coastal shelves were not as cold. The cold core 

 of the Labrador Current was smaller in October 

 and had a minimum temperature of — 1.38°C, 

 versus — 1.54°C in August (figs. 35 and 36). 

 Only a small amount of cold East Greenland 

 Current Water (<1°C) was found near the 

 surface on station 55 at the eastern end of 

 this section (fig. 36). 



The annual occupation of this section by the 

 Ice Patrol is valuable in monitoring the long- 

 term variability in the interchange of water 

 between the Labrador Sea and the North 

 Atlantic Ocean. This interchange plays an 

 important role in the transport of the Labrador 

 Current, which carries icebergs southward 

 from Baffin Bay to the North Atlantic shipping 

 lanes ofi" the Grand Banks of Newfoundland. 

 The 1969 values of volume transport, mean 

 temperature, and heat transport for the Lab- 

 rador and West Greenland Currents through 

 this section above a 1,500-meter reference level 

 are presented in table II with the values from 

 all previous occupations since 1948. The means 

 and standard deviations of these values are also 

 presented. 



Dinsmore and Moynihan (in press) point out 

 that large year-to-year fluctuations in the 

 volume transports of the Labrador and West 

 Greenland currents and in the net transport 

 mask the longer period cyclic changes. No gen- 

 eral correlation could be found between the 

 volume transport and the severity of the ice- 

 berg seasons even though the largest transports 

 of these currents occurred in 1957, which was 

 one of the most severe years in the annals of 

 the Ice Patrol. They also pointed out that there 

 is supporting evidence for an ovei'all net trans- 

 port into the Labrador Sea above the 1,500 

 meter reference level with sinking and outflow 

 at deeper levels. This was originally hypothe- 

 sized by Smith, Soule, and Mosby (1937) and 

 recently corroborated by data collected from 

 neutrally buoyant float measurements by Swal- 

 low and Worthington (1969). 



