Chapter 9 Ice Sheet Dynamics and Mass Balance

Abstract

This chapter discusses the dynamics of ice sheet and mass balance. Ice-sheet mass balance is the difference between the mass input and the mass output. The total balance includes both the surface mass balance processes and the ice-flow components. Mass is added to the surface from snowfall, condensation, and occasional rainfall. Mass is removed by evaporation, surface and bottom melting, water runoff, and iceberg discharge. The chapter discusses the radar altimeter measurement of ice-sheet surface elevations. Several methods have been used to create the digital elevation models (DEMs) of ice sheet topography from satellite altimetry. All methods involve mapping the data onto evenly spaced grids and correcting for the slope error, either before or after the mapping. Full DEMs of Greenland and Antarctica have been produced using triangularization or gridding procedures. A three-step inversion technique has also been demonstrated in small regions by Remy et al : first a large-scale reference surface is estimated, the residuals are mapped related to the undulations, and finally iteratively corrected for the slope error.