Tributaries of West Antarctic Ice streams revealed by RADARSAT interferometry

lnterferometric RADARSAT data are used to map ice motion in the source area s of four West Antarctic ice streams. The data reveal that tributaries, coi ncident with subglacial valleys, provide a spatially extensive transition b etween slow inland flow and rapid ice stream flow and that adjacent ice str eams draw from shared source regions. Two tributaries flow into the stagnan t ice stream C, creating an extensive region that is thickening at an avera ge rate of 0.49 meters per year. This is one of the Largest rates of thicke ning ever reported in Antarctica.