Discussion of Ice and 

 Environmental Conditions 



Background 



The offshore branch of the Labrador Cur- 

 rent is the main mechanism transporting ice- 

 bergs south to the Grand Banks and the North 

 Atlantic shipping lanes (figure 2). Its relatively 

 cold water keeps the deterioration of icebergs 

 to a minimum. 



Sea ice protects the icebergs from wave 

 action, the major agent in iceberg deteriora- 

 tion. If sea ice extends to the south and over 

 the Grand Banks of Newfoundland, the ice- 

 bergs will be protected longer as they drift 

 south. When the sea ice edge retreats in the 

 spring, large numbers of icebergs will be left 

 behind in the vicinity of the Grand Banks. If 

 the time of retreat of the sea ice edge is de- 

 layed by below-normal air and sea surface 

 temperatures, the icebergs will be protected 

 from melt longer and be expected to survive 

 to drift farther south. In these cases a longer 

 than normal ice season can be expected. 

 Less southerly sea ice extent or above nor- 

 mal air and sea surface temperatures may 

 result in a shorter season. 



Sea ice can impede the transport of ice- 

 bergs. The degree depends on the concen- 

 tration of the sea ice and the size of the ice- 

 bergs. The greater the sea ice concentration, 

 the greater the effect on iceberg drift. The 

 larger the iceberg, the less sea ice affects its 

 drift. 



The 1995 Season 



Figures 3 to 9 compare the sea ice edge 

 during the 1 995 ice year to the mean sea ice 

 edge. The mean sea ice edges were taken 

 from Cote (1989) and represent a 25 year 



average (1962-1987). The ice edge (sea ice 

 concentration > 1/10) is taken from the daily 

 Ice Analysis from the Ice Centre, Ottawa. 



Figures 10 to 21 show the Ice Patrol Lim- 

 its of All Known Ice (LAKI) and the daily sea 

 ice edge on the 1 5th and the last day of each 

 month during the ice season. The ice edge is 

 taken from the Ice Centre, Ottawa FICN2 daily 

 product. The edge plotted is a coarse numeric 

 representation of the daily Ice Analysis. These 

 figures show the distribution of all icebergs and 

 radar contacts tracked by MP's model at the 

 indicated times. Numerals are given for clar- 

 ity for those one-degree squares where six or 

 more targets are located. 



The following is a discussion of the ice 

 conditions, comparing those ice conditions 

 observed and modeled in 1995 with the 

 twenty-year IIP climatological LAKI (see Ap- 

 pendix E). 



December through February 



Through the period, sea ice growth along 

 the Labrador Coast and in East Newfound- 

 land waters appeared to be 2-4 weeks ahead 

 of normal (Figures 3-5). The sea ice edges 

 were observed further east and south than 

 mean positions. At the end of February, 43 

 icebergs were south of 48°N and the reported 

 LAKI (Figure 10) approximated the climato- 

 logical median position for March 1 5, thus trig- 

 gering the start ofthe Ice Patrol season on 28 

 February. 



March 



Throughout the month of March, a tongue 

 of sea ice extended eastward to approximately 

 46°N, 47°W, implying significant surfact circu- 



13 



