The Heat Balance of the Icy Slope of Adelie Land, Eastern Antarctica

Abstract

A complete but budget investigation was carried out in summer at a site in Adelie Land, some 100 km from the edge of the Antarctic ice sheet. For an average day, the all wave radiation budget based on the fluxes toward the surface being positive was positive for about 11 h, which is a short time considering that the sun was above the horizon between 22 and 24 h a day during the observational period. It is a result of the high albedo, which, on average, was found to be about 83%. Furthermore, with increasing cloudiness, a more positive radiation budget was found, which is in contrast to most studies at lower latitudes. The heat flux in and out of the snow cover was small, and showed a typical sinusoidal diurnal variation. The mean daily values of snow heat flux were negative, as the snow cover was warmed during the observational period. The latent heat flux was negative, on the average, as sublimation took place for most of the time. Deposition was observed only on a few nights. The sensible heat flux was negative around noon, but positive for most of the day, which means that the air above the surface was cooled, an inversion developed, and as the surface is inclined, gravitational flow (katabatic wind) started to occur. While the all-wave radiation balance had its minimum around midnight, the minimum temperature was observed some 3 h law, and the maximum wind speed occurred about 2 additional hours later. In summary, the mean warming of the snow, the sublimation and the negative all-wave radiation budget for most of the days were compensated by a positive sensible heat flux, which explains the frequent occurrence of the katabatic wind.