occupation of Section A-2 <iives an indication of 

 the early extent of the Labrador Current (fij;. 

 25). The 0°C isotherm extended to about 150 

 metere for nearly the entire section. The mini- 

 mum water temperature was less than — 1.6°C. 

 Tlie 0°C isotluMin is sijinificant as little iceber*; 

 meltinfi: will occur below this temperature. This 

 cold core extended at least to the Tail of the 

 Bank as can be seen in the vertical tempeiatuie 

 profile from the 18-10 April occupation of sec- 

 tion A-4. Here the 0°C isotheim extends below 

 150 meters, but the mininuun temperature was 

 just less than — 1.2°C. As Avas previously noted, 

 conditions had chanjied dramatically across this 

 section by the 9-10 May occupation (fi<i. 31). 

 However, from the vertical temperature pi'ofile 

 of the 13-14 ^lay occupation of section A-3, 

 (fig. 33) one can see that the core of the Labra- 

 dor Current was present although restricted 

 closer to continental slope. Temperatures less 

 than — 1.0°C were reported and the 0°C isotherm 

 was found deeper than 200 meters. By mid- 

 June surface water temperature along Section 

 A-3 had increased, but a cold coi'e with tempera- 

 ture less than — 1.4°C was reported, and the 

 0°C isotherm extended to 250 meters (fig. 37). 



Colder than normal conditions continued 

 through July and August. Each year the Fish- 

 eries Research Board of Canada and Memorial 

 University of Newfoundland condvict sections 

 across the Labrador Current fi'om southern 

 Labrador to the Tail of the Bank. Through 2 

 August below average temperatures were re- 

 corded to as far south as Flemish Cap. Even 

 toward the end of August, temperatures less than 

 — 1.7°C were recorded in the Labrador Current 

 near the Tail of tiie Bank (Tcmpleman, 1973). 

 Thus the generally colder than average water 

 conditions tended to reduce iceberg mortality 

 through melting in 1972. 



Air Temperatures 



Melting of the subaerial portion of iceberg is 

 directly related to the air temperature. From 



December through June, air temperatures along 

 the coast of Labrador and Newfoundland were 

 below normal. Monthly average temperatures 

 were most anomalous during the first part of 

 this period as for instance in February when the 

 average temperature was 4°C below normal (fig. 

 70). Temperatures approached normal as the 

 year progressed, but even as late as May (fig. 71) 

 temperatures were still 2°C below normal. Tem- 

 peratures recorded in the spring at four stations 

 along the eastern Canadian coast (Table 2) were 

 typical of these low values. It was not until 

 June that temperatures increased to above normal 

 and were high enough to cause substantial melt- 

 ing. Another indication of these conditions are 

 frost degree day accumulations. From seven of 

 the reporting stations in western Greenland and 

 eastern Canada, it can be seen that record ac- 

 cunnilations existed in each case (U.S. NAV- 

 OCEANO, 1972). Thus melting due to air tem- 

 perature was also less than normal in 1972. 



Precipitation 



As has been noted by Wolford (1972) and 

 other authors, iceberg deterioration is accelerated 

 during the passing of a storm and its associated 

 front. It was further concluded that this is 

 caused by increased rains as well as the increased 

 winds that accompany such stoi'ms. Wolford 

 (1972) also pi'esents an example demonstrating 

 the huge heat transfer that can result from such 

 rain. This rapid heat transfer causes increased 

 melting as well as increased internal stresses that 

 may cause the iceberg to calve. 



It has been noted that the niunber of storms 

 passing through the region of interest was 

 greater than normal during the winter of 1971- 

 1972 and the spring of 1972. However, due to 

 the colder than normal conditions which pre- 

 vailed, according to the weather log from 

 October 1971 through July 1972 at the repre- 

 sentative stations at Goose Bay, Newfoundland, 

 Gander, Newfoundland, and St. John's (Torbay), 



Taiu,f, 2. — Monthly Average Air Temperature and Deviation From Average In °C 



HOPEDALE _. 

 CAKTWKIGHT 

 ST. ANTHONY 

 ST. JOHN\S _._ 



11 



