APPENDIX A 



TAGGING OF ARCTIC ICEBERGS 



by R. Q. ROBE and T. S. ELLIS 

 U.S. Coast Guard Research and Development Center 



All of the early work with iceberg drift and 

 deterioration considered the entire population of 

 icebergs because of HP's limited detection capa- 

 bility (Cheney, 1951). When icebergs were near 

 the southern, western or eastern boundaries of 

 the defined ice area, they were considered highly 

 dangerous to shipping and a surface patrol ves- 

 sel would be assigned to follow these bergs until 

 they melted (Lenczyk. 1065). Only this con- 

 tinuous contact could assure that the iceberg 

 being tracked remained the same piece of ice. 

 Because of changes in the berg's shape by calv- 

 ing, rolling and melting, even repeated aircraft 

 nights could not make positive identification in 

 most cases (Lenczyk, 1965). During the 1960's, 

 interest in predicting the behavior of individual 

 icebergs increased for a number of reasons. First, 

 IIP now had confidence that aircraft could spot 

 and position bergs reliably over wide areas dur- 

 ing periods of good weather. Since the lack of 

 good weather has been a severe problem, a means 

 to predict the position between sightings is 

 needed. Second, even with accurate drift predic- 

 tion, the berg's rate of deterioration must be esti- 

 mated so that it Avill not be carried on the ice 

 plot for much more than a day after it has 

 melted, or worse, be eliminated from the ice plot 

 prior to melting. 



Answers to questions of drift and deterioration 

 prediction require that many individual icebergs 

 be studied over an extended period of time. 

 These studies require that the researcher be cer- 

 tain he is working with the same bergs and not 

 other icebergs in the same area. Early identifi- 

 cation attempts made use of dye to color the 

 sides of the berg. Kollmeyer (1966) used test 

 tubes filled with various dyes and shot them on 

 an arrow from a bow to mark a position on the 

 face of an iceberg. This mark was used as a 

 reference during a deterioration study. Over the 



years, IIP aircraft have repeatedly "bombed" 

 bergs with dye to aid in their identification. 

 This has limited utility because rolling and melt- 

 ing of the iceberg soon washes the color away. 

 Dye has a life of one to two days depending on 

 weather conditions and melting and rolling of 

 the ice. 



In 1974, the Coast Guard Oceanographic Unit 

 began a project to determine the best way to tag 

 an iceberg for identification and relocation. The 

 first approach was to encircle a berg with a float- 

 ing line (Hayes et ah, 1975). The 0.95 cm line 

 made of polypropylene was provided with addi- 

 tional floatation along its length (Figure A-l). 

 Radar reflectors and a Radio Direction Finder 

 transmitter were included as elements in the line. 



Two tagging attempts were made using this 

 method. On the first, three bergs were tagged. 

 The arrays were carried away in a storm and 

 only one was recovered. The line on the recov- 

 ered array was broken in two places. One break 

 occurred with such force that the ends of the 

 fibers were fused. There was no evidence of 

 chafing. The other break appeared to be the 

 result of chafing. The second attempt had quite 

 different results. Weather was fairly calm and 

 several bergs were tracked in dense fog for nine 

 days. However, the tagging arrays slipped re- 

 peatedly over or under the bergs. This necessi- 

 tated early recovery of the equipment which 

 drifted away from the iceberg, although the line 

 circle remained intact. This result was com- 

 pletely unexpected and probably was caused by 

 the berg snagging the line and rolling out of the 

 loop (Hayes et. ah, 1975). It should be remem- 

 bered that these icebergs were in an advanced 

 stage of deterioration and quite likely to roll. 



A similar experiment was carried out in 1976 

 (Brooks, 1977). After consultation with the 



A-l 



