TWOS ARCTIC DRIFTERS 

 1983 



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Figure B-1 



Tracks of TIROS Arctic Drifters deployed by IIP during 1983. 



#2618 crossed the Labrador Current perpen- 

 dicularly. The winds for the period 20-28 June 

 were from the south between 10 and 15 knots. 

 The average movement of TAD #2618 for this 

 period was 114°T at about 16 cm/sec which in- 

 dicates TAD #2618 was acting as a surface 

 drifter. 



The observed TAD "tagged" iceberg 

 movements corresponded well with the 

 movements predicted by the IIP drift model for 

 drift periods less than seven days. For periods 

 longer than seven days, the error accumulated 

 at a much faster rate. The error between actual 

 movement and that predicted by the model was 

 about 5 nm/day for drift periods less than 7 



days. Mountain (1980) found errors between ac- 

 tual and predicted iceberg movements of about 

 6 km/day (~3 nm/day) in evaluating the 

 ICEPLOT model. Therefore the additional use 

 of TADs to evaluate ICEPLOT will be con- 

 sidered. 



Considering the time of year and water 

 temperature, it is somewhat remarkable that all 

 of the TADs remained on the icebergs for 

 periods longer that two months. Since all of the 

 TADs remained aboard their respective 

 icebergs for a longer period than expected, the 

 information provided could be used to help 

 tune the IIP iceberg drift model, once the data 

 set is enlarged. 



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