A 20-year study of melt processes over Larsen C Ice Shelf using a
high-resolution regional atmospheric model: Part 1, Model configuration
and validation
Abstract
Following collapses of the neighbouring Larsen A and B ice shelves,
Larsen C has become a focus of increased attention. Determining how the
prevailing meteorological conditions influence the surface melt regime
is of paramount significance for understanding the dominant processes
causing melt and ultimately for predicting its future. A new,
high-resolution (4 km grid spacing) Met Office Unified Model (MetUM)
hindcast of atmospheric conditions and surface melt processes over the
central Antarctic Peninsula during the period 1998-2017 is developed for
this purpose. The hindcast is capable of reliably simulating observed
near-surface meteorology and surface melt conditions over Larsen C. In
contrast with previous model simulations, the MetUM captures the
observed east-west gradient in surface melting associated with foehn
winds, as well as the inter-annual variability in melt shown in previous
observational studies. The hindcast is applied to two case studies –
the months preceding the collapse of the Larsen B ice shelf in March
2002 and the high-foehn, high-melt period of March-May 2016 - to test
its ability to reproduce the atmospheric effects that contributed to
considerable melting during those periods. The results suggest that the
MetUM hindcast is a reliable tool with which to explore the dominant
causes of surface melting on Larsen C.