This project supports the completion of photogrammetry of ice stream B, Antarctica. Products of this work include: 1) accurate discharge calculations to refine mass balance determinations, 2) description of flow disturbances to show the influence of ice stream sides and of basal features in controlling flow, and 3) calculations of force budget for the production of maps of basal drag and sliding velocity that can be interpreted in of basal mechanics. The survey of the catchment area is also to be completed. The limits to the area will be better defined, accumulation rates mapped, and accurate divergence measurements obtained along selected flow bands. These data are necessary for the accurate calculation of the mass balance of the West Antarctic Ice Sheet. Field work is to be conducted in 1988-89 and data reduction in 1989-90.