AIRBORNE-RADAR STUDIES - ICE STREAM-A, ICE STREAM-B AND ICE STREAM-C,WEST ANTARCTICA

Digital airborne-radar data were collected during the 1988-89 Antarcti c field season in six gridded blocks covering the upstream parts of Ic e Streams A, B and C. An automated processing procedure was developed for picking onset times, converting travel times, interpolating missin g data, converting pressure-transducer readings, correcting navigation al drift, performing cross-over analysis and zeroing remanent cross-ov er errors. Cross-over analysis was used to remove the effects of tempo ral variations in atmospheric pressure and to estimate errors. Interpo lation between flight lines was carried out using the Kriging method. Surface elevation was referred to the Rapp Set A geoid by trying the g ridded surface to satellite-surveyed ground stations, using a planar-m odel fit. Maps of surface elevation, ice thickness and bottom topograp hy with standard-error estimates of 4-9 m for surface elevation and 30 -60 m for ice thickness and bottom topography were produced. These map s show that the locations of the ice streams are not clearly reflected in either the surface or basal topography, so are presumably controle d by basal or internal conditions, that there is no clearly demarcated transition zone between sheet flow and streaming flow, that there is no clear cut evidence for the capture of the catchment of Ice Stream C by Ice Stream B, but that Ice Stream B does drain virtually the entir e region between the lateral boundaries of Ice Streams A and C.