Modeling the mass and surface heat budgets in a coastal blue ice area of Adelie Land, Antarctica
Meteorological data recorded from December 12, 2008 to June 30, 2010 were analyzed to assess the Surface Energy Balance (SEB) in a blue ice area of Cap Prudhomme, Adelie Land (66°41’S, 139°55’E). The SEB was computed with a newly developed model forced by direct measurements and with a voluntarily limited number of parameters to better assess model sensitivity. Incoming shortwave radiation was corrected for the slope and orientation of the local terrain assuming direct and diffuse radiation components. Turbulent heat fluxes were assessed using the bulk aerodynamic approach. Heat conduction in the ice was computed by solving the thermal diffusion equation. Snow accumulation was modeled using ERA-interim total precipitation and a one-dimension erosion model. The surface heat budget and accumulation/erosion model accurately reproduced field observations. The occurrence of blue ice is linked with higher rates of erosion than in the surrounding snow covered areas, which may be caused by local flow divergence or snow not being redistributed from higher elevations. Melting occurs between December and February when incoming shortwave radiation is high. However, the SEB was closely linked to air temperature through the incoming longwave radiation and the turbulent sensible heat flux. Several warm events caused by cyclones intruding into the continent led to significant warming of the ice and high
melting rates. Intruding cyclones were also associated with high precipitation that led to significant accumulation. Except in blue ice areas, modeling suggests that expected higher precipitation in a warmer climate will result in more accumulation.
Authors: Favier, V., Agosta, C., Genthon, C., Arnaud, L., Trouvilliez, A., Gallée, H.