Analysis of the IIP Iceberg Drift Model. Cost and Operational Effectiveness Analysis for Selected International Ice Patrol Mission Alternatives. Annex H.

ADA300144 ADA300145 ADA300146 ADA300147 ADA300148 ADA300149 ADA300150 ADA300151 ADA300152 ADA300153 ADA300155 ADA300156 ADA300157

This report is Interim Report Volume 8 for the Cost and Operational Effectiveness Analysis for Ice Patrol Mission Analysis Study. The International Ice Patrol has developed a model of iceberg drift that plays a critical role in the overall modeling of iceberg locations and determining the Limits of All Known Ice. The drift model depends on the reported size of the iceberg and a number of environmental parameters. This report examines the structure of the drift model, reviews empirical evaluations of the model, and conducts an analytical and experimental sensitivity analysis of the model outputs with respect to the model parameters. The result of this analysis suggests that the local wind driven current portion of the deterioration model should be reexamined. The analyses indicate that the current speed magnitude is somewhat sensitive to errors in the wind speed that is provided as an input. Similar analyses with respect to errors in wind direction indicate that errors in wind direction may have a significant impact on estimated current direction. A comparison with a SAR current model yielded significantly different results. Other aspects of the drift model appear to provide a reasonable representation of the actual drift process. The analytical evaluation of the iceberg drift model reveals that there is little need for improved estimates of the environmental parameters for direct use in the drift model. The analysis illustrated the importance of correct classification. It is suggested that the current policy of classifying unknown icebergs as non-tabular medium icebergs be reexamined. Finally, the sensitivity of positional accuracy was clearly illustrated for the drift model.