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Center for Nonlinear Studies |
Iceberg calving provides an efficient mechanism to transfer larges amounts of ice to the ocean in a near-instantaneous fashion. This not only drastically changes the mass balance of a glacier/ice sheet, but the geometry of the glacial system. This in turn can have a profound effect on the flow of inland ice. Despite the important role that iceberg calving plays in the mass balance and dynamics of ice sheets, calving remains a poorly understood process that has eluded effective parameterization. In this presentation I will present ongoing research into an alternative approach of finding parameterizations of iceberg calving, whereby we use scaling arguments to elucidate physically consistent forms for a calving law. This approach is motivated, in part, by the success of scaling arguments in finding effective approximation in other problems where mathematical models are extremely complicated, e.g., the von Karman-Prandtl universal logarithmic law for wall-bounded turbulent shear flow agrees remarkably well with experiments. In this talk I will present one such (preliminary) calving law and show that it is able to, at least qualitatively explain (1) why temperate tidewater glaciers do not have floating termini; (2) why ice shelves do not protrude (much) beyond their embayment; and (3) why some glaciers form ice tongues and others do not. Moreover, since the law presented does not have any `tunable' knobs, future measurements (and maybe even present measurements) should provide ample opportunity to find those circumstances where the law is inaccurate and needs to either be amended or discarded.
Host: William Lipscomb, T-03