Environmental Conditions 



1 988 Season 



The wind direction along the 

 Labrador and Newfoundland 

 coasts can affect the iceberg 

 severity of each ice year. The 

 mean wind flow can influence 

 iceberg drift. Dependent upon 

 wind intensity and duration, 

 icebergs can be accelerated along 

 or driven out of the main flow of 

 the Labrador Current. Departure 

 from the Labrador Current nor- 

 mally slows their southerly drift, 

 and in many cases speeds up 

 their rate of deterioration. 



The wind direction and air tem- 

 perature affect the iceberg severity 

 of each ice year in an indirect way 

 by influencing the extent of sea 

 ice. Sea ice protects the icebergs 

 from wave action, the major agent 

 of iceberg deterioration. If the air 

 temperature and wind direction 

 are favorable for the sea ice to 

 extend to the south and over the 

 Grand Banks of Newfoundland, 

 the icebergs will be protected 

 longer as they drift south. When 

 the sea ice retreats in the spring, 

 large numbers of icebergs are left 

 behind on the Grand Banks. Also, 

 if the time of sea ice retreat is 

 delayed by below normal air 

 temperatures, the icebergs will be 

 protected longer, and a longer 

 than normal ice season can be 

 expected. The opposite is true if 

 the southerly sea ice extent is less 

 than average, or if above normal 

 air temperatures cause an early 

 retreat of sea ice from the Grand 

 Banks. 



The following discussion summa- 

 rizes the environmental conditions 

 along the Labrador and New- 

 foundland coasts for the 1988 ice 

 year. 



January: The monthly mean 

 pressure of the Icelandic Low was 

 1 mb lower in January than 

 normal (Figure 2). This resulted in 

 stronger, slightly more westerly 

 winds along the Labrador Coast 

 (AES, 1988), and strong westerly 

 winds over the waters east of 

 Newfoundland in January. 



Febmary: A double-centered 

 Icelandic Low formed this month 

 on either side of Iceland (Figure 

 3). This is not unusual, but when 

 a double-centered Icelandic Low 

 forms, the two centers are usually 

 near Denmark Strait and off 

 Nonway (Mariners Weather Log, 

 1988b). The two lows were also 

 deeper than normal. This led to a 

 -8 mb anomaly centered in Davis 

 Strait (Mariners Weather Log, 

 1988b), and a stronger than 

 normal northwesterly flow along 

 the Labrador Coast. A westerly 

 flow dominated the waters east of 

 Newfoundland. The flow was 

 nrwre offshore than normal in both 

 of these areas (AES, 1988). 



March: The Azores-Bermuda High 

 dominated the western North 

 Atlantic in March, and its monthly 

 mean pressure was 6 mb higher 

 than normal (Figure 4). This 



displaced the Icelandic Low to the 

 west, and caused a -4 mb anom- 

 aly in the Labrador Sea (Mariners 

 Weather Log, 1988b). The winds 

 in March were near normal, 

 however, with northwesterly winds 

 along the Labrador Coast and 

 westerly winds east of Newfound- 

 land (AES, 1988). 



April: In April, the Azores- 

 Bermuda High usually begins to 

 build in strength while the Ice- 

 landic Low begins to decrease in 

 intensity (Mariners Weather Log. 

 1988c). In 1988, the Azores- 

 Bermuda High was near its normal 

 position and intensity (Figure 5). 

 However, with a monthly mean 

 pressure 4 mb lower than normal, 

 the Icelandic Low was more 

 intense and farther west than 

 normal. This resulted in strong, 

 northeasterly winds along Labra- 

 dor and eastern Newfoundland 

 rather than the normal lighter, 

 more northerly winds. 



May: In May, the Azores-Ber- 

 muda High began to dominate the 

 North Atlantic (Figure 6). It was 

 slightly stronger than normal, but 

 storm activity to the north kept it 

 from its normal expansion (Mari- 

 ners Weather Log, 1988c). The 

 resulting flow pattern along 

 Labrador and eastern Newfound- 

 land was light northeasterly winds 

 rather than the normal light 

 southwesterlies. 



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