tion was the iceberg they had seen 

 in the previous photographs. It is 

 best to assume that 24 April was the 

 last day of useful iceberg movement 

 data reported by 2612 because of 

 the lack of any evidence to the con- 

 trary. 



Figures 3 and 4 present the filtered 

 position data and velocity compo- 

 nents of TADs 4500 and 261 2. The 

 reason for the short gap between 

 the deployment position and the first 

 plotted filtered position for each is 

 that several points were lost filling 

 the filter. This is also true at the end 

 of the position records. The entire 

 record of 4500 represents iceberg 

 movement. The filled triangle along 

 261 2's track and in the plot of the 

 velocity components marks the date 

 when the TAD was last thought to 

 have been on the iceberg (24 Apnl, 

 114). There was one short period, 

 from 6 to 7 Apnl (96-97), when the 

 data return was poor, with only one 

 fix for each buoy over a 40-hour 

 period. TAD 2612 transmitted po- 

 sitions until 16 September (259) as 

 it moved eastward across the north 

 Atlantic. 



Soring Deployments 



The goal of the spring deployments 

 was to study the summer movement 

 of icebergs from the southern La- 

 brador coast to the Ice Patrol opera- 



tions area, the northern boundary 

 which is at 52° N. There are few 

 long-term (>1 days) iceberg tracks 

 reported in the literature. Using 

 satellite-tracked platforms, Robe 

 (1979) tracked two icebergs and 

 Anderson ( 1 983) three in the region. 

 Of the five, four moved eastward to 

 the north of Flemish Cap, never 

 crossing south of 48°N. This east- 

 ward movement is consistent with 

 the observation that, in some years, 

 few icebergs are encountered south 

 of 48°N despite large pre-season 

 iceberg populations along the La- 

 brador coast. 



Ice Patrol depbyed a TAD on each of 

 two large bbcky icebergs atong the 

 Labrador Coast east of Hamilton Inlet. 

 The deployments were made with the 

 cooperation of the Canadian Coast 

 Guard, in particular the CCGS ANN 

 HARVEY, whose helicopter made the 

 deployments. The deployments were 

 coordinated by the Canadian Coast 

 Guard Regional Ice Operations Center 

 in St. John's, Newfoundland. Detailed 

 measurements of the icebergs were not 

 made. Both icebergs were in water less 

 than 200 m deep when the TADs were 

 placed aboard. Table 2 summarizes 

 the deployment data. 



TAD 4504 provided a 38-day posi- 

 tion record (Figure 5), and it is likely 

 that the entire record represents 

 iceberg movement. The data return 



was excellent, with 8-12 positions 

 recorded on most days. The iceberg 

 tracked by TAD 4504 spent the en- 

 tire 38-day period on or near 

 Hamilton Bank, mostly in water less 

 than 200 m deep. 



After its deployment, 4504 moved 

 northward until 27 June (178), mostly 

 at speeds of atx)ut 10 cm/s. The 

 fastest iceberg movement recorded 

 by 4504 occurred dunng the subse- 

 quent southward track (27 June - 3 

 July, 178-184), most of whichwas in 

 slightly deeper water (~ 230 m). 

 During this period the iceberg moved 

 at 10-30 cm/s. 



After this period, the iceberg returned 

 to the shallow water on Hamilton 

 Bank, where for a 1 0-day period (3- 

 13 July, 184-194) it moved very 

 slowly. It is likely that the iceberg 

 during this period was dragging in- 

 termittently along the bottom. The 

 water depth in the vicinity was about 

 150 m. Because there were no 

 detailed size measurements taken, 

 it is not possible to say with certainty 

 that the iceberg was grounded. 

 However, for a large iceberg (123- 

 213 m long), a keel depth of about 

 150 m is a reasonable figure, so 

 grounding was possible. 



On 6 July ( 1 87) 4504 began a persistent 

 southward movement over Hamilton 

 Bank, beginning at speeds less than 1 



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