HR: 0830h
AN: C11D-0856    [PDF]
TI: A Model of Ice-Shelf Thermodynamics and Surface Hydrology Under Melting Conditions With an Application to the Recent Disintegration of the Larsen A and B Ice Shelves
AU: * Sergienko, O
EM: olga@uchicago.edu
AF: The Department of the Geophysical Sciences, The University of Chicago, 5734 S. Ellis Ave, Chicago, IL 60637 United States
AU: MacAyeal, D R
EM: drm7@midway.uchicago.edu
AF: The Department of the Geophysical Sciences, The University of Chicago, 5734 S. Ellis Ave, Chicago, IL 60637 United States
AB: Break-up of Larsen A and B ice shelves in 1995 and 2002, respectively, is thought to be a consequence of extensive warming within the Antarctic Peninsula region observed in recent decades. The most notable glaciological effect of this warming has been the emergence of pervasive surface melting on the two ice shelves in the summers prior to their disintegration.Indeed, the mechanical effects of surface meltwater in the propagation and deepening of surface and basal crevasses has been proposed as the mechanism by which the ice shelves were fractured to the point of disintegration. To develop an understanding of how surface conditions on the Larsen Ice Shelves converted from essentially dry, polar conditions to wet, temperate conditions, we have developed a simple model that describes the hydrological and thermodynamic evolution of surface firn and melt under warming environments. Energy conservation aspects of the model are designed to simulate the formation of subsurface melt due to the absorbtion of solar radiation and the formation of in situ ice layers in response to latent heat release. Hydrological aspects of the model are concerned with how meltwater percolates down and re-freezes at colder horizons. Storage aspects of the surface hydrology are parameterized in a simple manner so that the evolution of metwater ponds and water-filled surface crevasses can be simulated as a consequence of progressively saturating the firn with meltwater and impermeable re-frozen ice lenses. The model is tested by comparing its evolution with observations of the Larsen Ice shelf under model forcing conditions (atmospheric pressure, temperature, precipitation, specific humidity and wind speed) representative of conditions on Larsen B ice shelf in the years prior to it's disintegration.
DE: 1640 Remote sensing
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2003 Fall Meeting