quires much extrapolation, it is felt that in this 

 case the second reason is the primary cause of 

 the variation in the transport values. In addi- 

 tion, Hill et al. (1!'74) modified their geostrophic 

 values with data from current meters located 

 along the Grand Banks-Flemish Cap section. 

 Although the British value is much greater than 

 the Coast Guard's, their current profiles (fig. 64 

 and 65) are similar. In both cases the core of 

 the Labrador Current is just to the east of the 

 continental slope and an anomalous northward 

 flow is just to the west of Flemish Cap. Com- 

 paring these data with available historical data, 

 the Russian value is slightly greater than their 

 normal (Kudlo. 1973) and the Coast Guard 

 figure is higher than the running average which 

 was terminated in 1964 (Kollmeyer et al., 1965). 

 Thus it can be said that the Labrador Current 

 was well developed in the first part of April. 



The dynamic heights from the above occupa- 

 tion of section A-2 and those from the remainder 

 of the three cruises conducted for IIP were con- 

 toured and are shown in figures 53, .54, and 55. 

 The Labrador Current was well developed as far 

 south as the Tail of the Bank through June with 

 currents in excess of 50 cm/sec being foimd in 

 the core. The volume transports generally in- 

 ci-eased through May before slackening in June. 

 Such condition are extremely conductive to ice- 

 bergs, southward drift. 



While the flow of the Labrador Current was 

 steady during this period, large fluctuations oc- 

 curred in the North Atlantic Current and the 

 dynamic trough region. The April dynamic 

 topography was similar to the normal (fig. 41). 

 However, by the May survey, conditions had 

 changed dramatically and did not resemble 

 either the April 1072 chart or the May normal 

 (fig. 44). The dynamic trough had expanded 

 and contained two distinct sections. The lower 

 portion of the trough was adjacent to the Labra- 

 dor Current as expected, but just to the east was 

 a slightly higher portion of the trough which 

 was dynamically flat. The temperature in this 

 part of the trough was nnich higher than in the 

 lower portion indicating that it may have been 

 formed as a result of aTi eddy/meander separat- 

 ing from the North Atlantic Current. Another 

 imusual condition existed south of the Tail of 

 the Bank where the flow of the Labrador Cur- 

 rent was abruptly blocked by a meander of the 

 North Atlantic Current indicated by the presence 



of warm saline water (figs. 31 and 32). Since 

 the June survey was abbreviated, it is impossible 

 to deteiniine if these conditicms had returned to 

 noi-mal at that time. 



Waves/Sea Ice 



There are two ways that iceberg drift is af- 

 fected by sea ice. First, surface waves are rap- 

 idly dampened as they travel vmder this ice 

 which reduces the eroding effect of these waves 

 on icebergs. Second, large amounts of sea ice 

 will keep the icebergs from drifting into bays 

 and inlets along the coast (Schell, 1961). The 

 presence of sea ice is an indication that the ice- 

 berg is in cold water where no deterioration will 

 occur. From December through June, the sea 

 ice extended farther south and east than normal 

 (Sanderson, 1972a, Sanderson, 1972b, and San- 

 derson, 1972c). The greatest departure from the 

 normal occurred in January (fig. 66), and even 

 as late as May, sea ice remained off the coast of 

 Newfoundland (fig. 67). Thus during the win- 

 ter of 1971-1972, lieavy ice conditions were such 

 as to reduce the mortality of icebergs drifting 

 southward along the eastern Canadian coast. 



Sea Temperatures 



It is obvious that with increased sea tempera- 

 tures, more iceberg melting will occur. But for 

 the entire first half of 1972 the water in the area 

 of interest was colder than normal. It is clear 

 from Sanderson (19721)), and Sanderson (1972c) 

 that the average sea surface temperatures were 

 below normal along the Labrador and eastern 

 Newfoundland coasts for the first six months of 

 1072. Specific temperatures as much as 11°C 

 colder than normal were reported in the Grand 

 Banks area (Bailey, 1973). This unseasonably 

 cold condition caused the 0°C sea surface iso- 

 therm to remain south of Newfoundland 

 throughout March (fig. 68) (Royal Met. off., 

 1972a), and even as late as June this isotherm 

 extended as far south as northern Newfoundland 

 (fig. 69) (Royal Met. oft"., 1072b). 



Colder than normal conditions also were found 

 at depth. Burmakin (1973) noted that tempera- 

 tures along sections 8-A, 7-A, 6-A, 4-A, and 

 3-A were between normal and 2.2°C below nor- 

 mal at various times from November through 

 May in the upper 200 meters. Sevei-al IIP sec- 

 tions also indicate these cold conditions. The 

 vertical temperature profile from the 7-8 April 



10 



