Iceberg Drift and 

 Deterioration 



process described above to 

 create a "quasi-geostrophic" 

 current from the TOD drift data. 

 Tiiis apparent over-estimate of 

 the wind velocity would adversely 

 affect the calculation of the 

 Ekman wind current subtracted 

 from the TOD motion. This study 

 of the FNOC winds was not meant 

 to be exhaustive but was an effort 

 to identify possible sources of 

 error in our calculations of the 

 Ekman wind driven current. 



The second part of the cmise was 

 an iceberg drift and deterioration 

 study conducted between 1 6 

 and 22 July 1984. The primary 

 objective of the second phase 

 was to evaluate the iceberg 

 deterioration model being used 

 by IIP. The iceberg deterioration 

 model was used operationally 

 during both the 1983 and 1984 

 seasons. The model is described 

 in detail in Anderson ( 1 983b) . 

 We hoped to locate a group of 

 icebergs of various sizes and 

 follow them and observe their 

 deterioration. By following the 

 melting icebergs, obtaining drift 

 data was only a matter of 

 recording the iceberg position 

 periodically. 



A medium iceberg approximately 

 1 20m long by 1 1 5m wide by 37m 

 high was located on the 

 afternoon of 1 6 July in position 

 48041 .9'N 46O20.4'W (Figure B- 

 8). We were able to follow this 

 iceberg until the morning of 22 

 July before we had to depart the 

 area. At our departure, the 

 iceberg was about 40m long, 28m 

 wide, and 12m high (Figure B-8). 

 The dimensions given here and 

 discussed below will be maximum 

 dimensions in each phase 

 regardless of shape. 

 Unfortunately, we were not able 

 to locate a group of icebergs to 

 observe. 



Most of the size measurements of 

 the iceberg were determined 

 using a reticulated laser range 

 finder. Due to extremely poor 

 visibility (less than 200m) during 



Table B-4 Actual vs 



Date/Time 

 July/Zulu 

 16/1400 

 16/1800 

 17/0600 

 17/1800 

 18/0600 

 18/1800 

 19/0600 

 19/1800 

 20/0600 

 20/1800 

 21/0600 

 21/1800 

 22/0600 



Modelled Iceberg Deterioration 



Predicted Deterioration Due to 



Actual 

 Length 

 120m 

 137m 

 114m 

 102m 

 87m 

 90m 

 91m 

 87m 

 67m 



60m 

 53m 

 40m 



Predicted 

 Length 

 120.0m 

 117.7m 

 110.3m 

 105.1m 

 99.2m 

 92.3m 

 85.5m 

 79.6m 

 73.8m 

 69.0m 

 64.7m 

 60.4m 

 54.9m 



Insolation 



.01m 

 .01m 

 .01m 

 .01m 

 .01m 

 .01m 

 .01m 

 .01m 

 .01m 

 .01m 

 .01m 

 .Dim 



Buoyant 

 Convection 



.03m 

 .10m 

 .10m 

 .10m 

 .11m 

 .11m 

 .11m 

 .11m 

 .11m 

 .12m 

 .12m 

 .13m 



Wind-Forced 

 Convection 



.20m 

 .63m 

 .66m 

 .66m 

 .68m 

 .68m 

 .72m 

 .72m 

 .72m 

 .79m 

 .79m 

 .84m 



Wave 

 Erosion 



2.08m 

 6.54m 

 4.46m 

 5.09m 

 6.06m 

 5.95m 

 5.08m 

 4.98m 

 3.99m 

 3.41m 

 3.41m 

 4.49m 



64 



