Abstract: Megadune fields occupy large areas in the interior of the East Antarctic ice sheet and are the result of unusual snow accumulation and redistribution processes. They therefore are important to surface mass balance and ice core interpretation. Field observations (GPS, GPR, and surface measurements) have provided a detailed description of megadune sedimentation and morphology over a 70 km2 area, located 200 km east of Dome C. A combination of remote sensing analysis (using Landsat and satellite radar altimetry) and field measurements indicate that slope in the prevailing wind direction (SPWD) and climatic conditions play a crucial role in megadune genesis. The megadune areas tend to be characterized by slightly steeper regional slope and the presence of highly persistent katabatic winds. The megadunes represent 2 to 4 m amplitude waves of 2 to 5 km wavelength formed by variable net accumulation, ranging between 25% (leeward faces) to 120% (windward faces) of the accumulation in adjacent nonmegadune areas. Leeward faces are characterized by glazed, sastrugi-free surfaces and extensive depth hoar formation. Windward faces are covered by large rough sastrugi up to 1.5 m in height.

Abstract: We present data of nine Automatic Weather Stations (AWS), which are located in Dronning Maud Land (DML), East Antarctica, since the austral summer of 1997. Potential temperature and wind speed are maximum at the sites with the steepest surface slope, i.e., at the edge of the Antarctic plateau. Specific humidity and accumulation decrease with elevation and distance from the coast. The annual average energy gain at the surface from the downward sensible heat flux varies between ?3 W m?2 and ?25 W m?2, with the highest values at the sites with the largest surface inclination and wind speeds. The net radiative flux is negative and largely balances this sensible heat flux and ranges from ??2 W m?2 to ??28 W m?2; maximum values can be linked to maxima in surface slope and wind speed, and suggest a strong connection between the heat budget and the katabatic flow in DML. The average latent heat flux is generally small and negative (??1 W m?2) indicating a slight net mass loss through sublimation.