Undulating topography on the Antarctic ice sheet revealed by NOAA AVHRR images

Abstract

Undulating topography on the East Antarctic ice sheet was clearly revealed by NOAA AVHRR. The following three patterns of undulating topography were detected by using high-pass filtered images from the visible to thermal infrared channels. In coastal regions (below 2000 m a.s.l.), undulation can be clearly detected by the fluctuation of reflectance in visible channel. It has wavy structure with spacing less than 10 km and alignment at a right angle to the ice-flow lines. In the katabatic zone (from 2000 m a.s.l. to 3000 m a.s.l) well defined fluctuations of albedo stpectrum can be seen with spacing from 10 km to 20 km, aligned at right angles to the ice-flow lines or prevailing katabatic wind direction. Ground-survey data show that the undulating topography is associated with large variations of net accumulation rate. On the inland plateau (above 3000 m a.s.l.), undulation can be clearly seen in the fluctuation of thermal infrared channel in winter. Ground-survey data show that the signal corresponds to the undulating topography. The alignment of the undulation is at a right angle to the ice-flow lines and the spacing is longer than 20 km. The characteristics of these undulations represent the ice-flow dynamics and accumulation anomaly.