Role of Snow Distribution Processes in Antarctic Sea Ice Mass Balance

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Arctic and Antarctic sea ice exhibit some important differences. Almost all Antarctic sea-ice is seasonal, disappearing in summer. Antarctic sea-ice is usually thinner, more broken, rougher and more easily moved by the wind and waves than the multiyear Arctic pack. Arctic ice extent has been notably rapidly depleting over recent years, while Antarctic ice has been, if anything, expanding. Snow plays an important role but poorly documented role in Antarctic sea ice mass balance, sea ice surface properties and sea ice ecosystem dynamics. Precipitation over the Southern Ocean is predicted to increase as a consequence of atmospheric warming, but the role such a precipitation increase might play in sea ice mass balance is unclear. Recent work suggests that patterns of snow distribution on sea ice owes more to wind transport and re-deposition of snow than to precipitation. Also more than half of all snowfall may be lost to open leads. A combination of field measurements made from aboard two international Antarctic research cruises will set out with a number of questions in mind: 1) What are the spatial relationships between snow depth distribution and ice surface morphology? 2) Can a statistical description of the snow depth distribution be developed as a function of ice type or morphology? 3) What factors control the mass flux of blowing snow? 4) How does surface roughness and topography control blowing snow transport and deposition into deformed ice and leads? 5) Can snow accumulation and distribution on sea ice be quantified as a function of precipitation and ice conditions? These questions are central to informing our knowledge of Antarctic sea-ice properties and their representation in climate models is of wide interest.