Appendix D 



Iceberg Drift Model Comparisons with Ice Island Position Data 



MST3 Allie Rodgers 

 LT Scott Stoermer 



Abstract 



The analysis of 13 days of iceberg tracking data for the purposes of testing the drift 

 characteristics of the International Ice Patrol's iceberg drift and deterioration model is 

 presented. The data collection, methods and analysis are discussed. A historical 

 background section follows the project conclusions and briefly outlines the historical 

 aspects of Ice Patrol's iceberg marking and tracking techniques as well as Ice Islands. 



Introduction 



The iceBerg Analysis and Prediction System (BAPS) has been extensively tested over the 

 years to help ensure that the Canadian Ice Service and the International Ice Patrol (IIP) use the 

 best information possible to estimate iceberg drift and deterioration. The region of the North 

 Atlantic Ocean that IIP is concerned about is highly complex as the Gulf Stream (GS), Labrador 

 Current (LC) and North Atlantic Current (NAC) interact in a region of very shallow bathymetry. 

 Coupled with dynamic, often harsh weather, the intricacies of this ocean-atmosphere system make 

 its prediction very difficult and require IIP to constantly concern itself with the differences 

 between the actual ocean and the BAPS ocean. 



The appearance of very large tabular icebergs in the region of the Grand Banks of 

 Newfoundland for the second consecutive year provided IIP with some unique opportunities 

 during the 2003 ice season. Most notably, IIP was able to deploy a Compact Air Launched Ice 

 Beacon (CALIB) and gather approximately two weeks of real-time iceberg position information 

 during the late spring. IIP's archive of the environmental forcing files used by BAPS provided 

 the means to test the model after the fact. 



CALIB Data and Methods 



The CALIB used by IIP during this experiment was provided by the Canadian Ice Service 

 and originally procured from METOCEAN. On May 5, 2003 (during Ice Reconnaissance 

 Detachment #7), CALIB #1 1247 was deployed onto an iceberg measuring approximately 250 m x 

 100 m in position 46.873°N/47.927°E (see photo collage on front cover and Figure 1). The 

 beacon was deployed from an altitude of 350 feet at approximately 150 knots indicated air speed 

 from the cargo ramp of a Coast Guard HC- 1 30H. Data was gathered via the ARGOS system until 

 18 May at which time the CALIB stopped transmitting for unknown reasons. Presumably, the 

 CALIB was lost to the ocean when the iceberg broke apart or rolled as it deteriorated. 



Thirteen days of position data were gathered consisfing of 1 10 individual position fixes 

 (Figure 1). Each fix was placed in a confidence level category by ARGOS based on position fix 

 quality. ARGOS uses a fix quality of one through three with three designating the highest level 

 of confidence. For the comparison experiments conducted here, only the 57 highest quality fixes 

 (fix category 3) were used. 



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