Surface lowering of the ice ramp at Rothera Point, Antarctic Peninsula, in response to regional climate change
Level-line surveys at a number of sites on the Antarctic Peninsula since
the early 1970s have shown a lowering of the ice surface elevation in areas where the
climate is warm enough for melting to occur during summer. Results are presented here
from annual surveys on the ice ramp at Rothera Point. Over an 8 year period, a large
proportion of the ramp shows a generally steady reduction in surface elevation. The
uppermost part of the ramp shows no clear trend. The ice ramp has suffered a mean rate
of surface lowering of 0.32 m a-I w.e. over the period of the surveys, which is similar to that
seen at other sites on the Antarctic Peninsula. Measured ice velocities on the ramp are low,
so the surface lowering can be attributed directly to changes in surface mass balance. The
surveys coincide with a period of long-term increase in temperature and ablation seen in
meteorological records. Comparison of the observed surface lowering with temperature
data shows a good agreement, and we conclude that increasing air temperatures in the
region will raise ablation and increase the recession rate of the ice ramp.
Authors: Smith, A.M., Vaughan, D.G., Doake, C.S.M., Johnson, A.C.