The Surface Mass-Balance of Marie Byrd Land, Antarctica: Data Interpretation and Application

Abstract

A method is described to determine accurate and precise mass balance from bamboo poles at the surface of the ice sheet upstream from Byrd Station, Antarctica. The method includes corrections for snow and firn settling and for the migration of anchoring position along the pole. Methods for determining snow and firn densities from pits using sawed blocks (after Schytt 1958) are described. Although our sawed block data contain a systematic error, this technique provides much more precise densities than the snow sampler technique. We recommend an improved sawed block technique for future work. The surface mass-balance is largest near the ice crest and shows variations that are related to surface slope. The pattern is probably related to orographic precipitation from air masses originating in the Amundsen Sea and to katabatic winds. The importance of spatial surface mass-balance to deep core interpretation is discussed.