Radar-based subglacial lake classification in Antarctica

Abstract

Subglacial lakes in East Antarctica can be separated into four categories specified by radar reflection properties. Definite lakes are brighter than their surroundings by at least 2 dB (relatively bright) and both are consistently reflective (specular) and have a reflection coefficient greater than -10 dB (absolutely bright). Dim lakes are relatively bright and specular but not absolutely bright, indicating nonsteady ice dynamics. Fuzzy lakes are both relatively and absolutely bright, but not specular, and may indicate saturated sediments or "swamps." Indistinct lakes are absolutely bright and specular but no brighter than their surroundings. Lakes themselves and the different classes of lakes are not arranged randomly throughout Antarctica but are clustered around ice divides, ice stream onsets, and prominent bedrock troughs, with each cluster demonstrating a different characteristic lake classification distribution. The lake classification algorithm expands on previous studies and demonstrates a novel way to characterize icewater interactions in East Antarctica. Copyright 2007 by the American Geophysical Union.