Assessing Controls on Ice Dynamics at Crane Glacier, Antarctic Peninsula Using a Numerical Ice Flow Model

Abstract:

Since the collapse of the Larsen A and B ice shelves on the eastern Antarctic Peninsula, ice flow from the shelves’ former tributary glaciers has accelerated significantly. The terminus position and ice speed of glaciers on the Antarctic Peninsula have been previously correlated to ocean conditions in more recent years. However, the current understanding of important controls on glacier dynamics around the Antarctic Peninsula is limited by sparse ocean observations at glacier margins and estimates of submarine melting rates. Here, we used a width- and depth-integrated numerical ice flow model to investigate the influence of changing ocean conditions on Crane Glacier, former Larsen B tributary, following the collapse of the ice shelf. Specifically, we used satellite-derived observations of speed, terminus position, and elevation change to constrain the dynamic history of the glacier. Bed elevations were estimated via mass conservation and constrained by the NASA’s Operation Ice Bridge mission and bathymetry observations. Environmental forcing was prescribed using surface mass balance estimates from the RACMO2.3 climate model and calving and submarine melting parameterizations tuned to calibrate the numerical model so that it reproduces temporal patterns in terminus position (for calving) and surface meltwater runoff and iceberg melting (for submarine melting). The results demonstrate the model’s sensitivity to the calving parameterization and to the environmental forcing parameters.