Abstract
Surface melt is an important process for the stability of ice shelves,
and therewith the Antarctic ice sheet. In Antarctica, absorption of
solar radiation is mostly the largest energy source for surface melt,
which is further enhanced by the snowmelt-albedo feedback (SMAF):
refrozen snow has a lower albedo than new snow, which causes it to
absorb more solar radiation, further increasing the energy available for
surface melt. This feedback has previously been shown to increase
surface melt by approximately a factor of 2.5 at Neumayer Station in
East Antarctica. In this study, we use a regional climate model to
quantify SMAF for the entire Antarctic ice sheet. We find that it is
most effective on ice shelves in East Antarctica, and is less important
in the Antarctic Peninsula and on the Ross and Filchner-Ronne ice
shelves. We identify a relationship between SMAF and average summer air
temperatures, and find that SMAF is most important around 265±2 K. On a
sub-seasonal scale, we identify several parameters that contribute to
SMAF: the length of dry periods, the time between significant snowfall
events and snowmelt events, and prevailing temperatures. We then apply
the same temperature-dependency of SMAF to the Greenland ice sheet and
find that it is potentially active in a narrow band around the ice
sheet, and finally discuss how the importance of SMAF could change in a
warming climate.