This award is for support of research to study the portion of the West Antarctic Ice Sheet which feeds in to the Ross Ice Shelf. Satellite image analysis, ground surveying, and radar soundings by both airborne and ground-based systems comprise the necessary elements of this research. These activities are an essential part of the Siple Coast Project and the new SeaRISE initiative which have as goals: 1) Determination of the configuration and mass balance of the Siple Coast region of the West Antarctic ice sheet, 2) Determination of the physical controls of ice flow in this region, and 3) Prediction of the future behavior of this region using numerical models. These models will be enhanced by: 1) Completion of the surveys in the catchment areas of all the ice streams, 2) Determination of surface velocities in ice streams D and E, 3) Measurements of the discharge flux of ice streams D and E, 4) Examination of ice stream flow in the area of a surface undulation using satellite imagery, 5) Quantify the relative motion between the surface and bed in the grounded region just upstream of the grounding line.