Sensitivity of iceberg drift to initial size distribution
Date
2009-10-21T17:41:57Z
Authors
Burton, Justin E.
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Abstract
Historical interest in regards to icebergs have ranged from their ability to provide a freshwater source to the destructive forces they are able to impose on maritime structures. As well, recent studies have focused on the possible influences icebergs may have on the climate system. Initial investigations of the advective and deteriorative patterns of iceberg armadas under normal ablative conditions suggest that they are sensitive to their initial size distributions (Silva et al., 2006). This work extends these initial examinations further. The sensitivity of the ice and meltwater patterns to a range of initial iceberg size distributions for a collapse of the Ronne-Filchner ice shelf is investigated. A numerical iceberg model is developed, which simulates the drift and melting of iceberg populations specified in selected size categories. The model treats the population of icebergs as a continuum rather than focusing on the trajectories of individual icebergs. Oceanic and atmospheric forcing fields are provided by the University of Victoria Earth System Climate Model (UVic ESCM) and the National Centers for Environmental Prediction (NCEP) 40-year reanalysis project (Kalnay et al., 1996), respectively. Meltwater from large icebergs (with a total height of approximately 1180 m) originating from the Ronne-Filchner ice shelf reaches as far north as 58 S, compared to 63 S for small icebergs (with a total height of approximately 10 m). Also, the equivalent volume of small icebergs melts away completely within the first five years, as compared to 50 years for the large icebergs. Therefore, populations containing greater amounts of small icebergs are found to lead to a larger freshwater flux, as well as accumulate meltwater closer to the original location of the Ronne-Filchner ice shelf. These findings are important when examining the potential effect of ice shelf collapse on deep and intermediate water formation rates and associated climate feedbacks.
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Keywords
iceberg model, climate, icebergs