||Ice sheet mass loss caused by dust and black carbon accumulation
Goelles, T. ,
Bøggild, C. E.Greve, R.
1856 , 2015-04-23 , Copernicus Publications on behalf of the European Geosciences Union
Albedo is the dominant factor governing surface
melt variability in the ablation area of ice sheets and glaciers.
Aerosols such as mineral dust and black carbon (soot) accumulate
on the ice surface and cause a darker surface and
therefore a lower albedo. The darkening effect on the ice surface
is currently not included in sea level projections, and the
effect is unknown. We present a model framework which includes
ice dynamics, aerosol transport, aerosol accumulation
and the darkening effect on ice albedo and its consequences
for surface melt. The model is applied to a simplified geometry
resembling the conditions of the Greenland ice sheet,
and it is forced by several temperature scenarios to quantify
the darkening effect of aerosols on future mass loss. The effect
of aerosols depends non-linearly on the temperature rise
due to the feedback between aerosol accumulation and surface
melt. According to our conceptual model, accounting
for black carbon and dust in future projections of ice sheet
changes until the year 3000 could induce an additional volume
loss of 7 %. Since we have ignored some feedback processes,
the impact might be even larger.