Spatial stability of Ice Stream D and its tributaries, West Antarctica, revealed by radio-echo sounding and interferometry

Abstract

It has been shown recently that ice streams are fed by fast-flowing tributaries occupying well-defined subglacial troughs and with shared source areas. Here, ice-penetrating radio-echo sounding (RES) data are analyzed in conjunction with ice surface velocities derived from interferometric synthetic aperture radar (InSAR), to determine the englacial properties of tributaries feeding Ice Stream D, West Antarctica. All of Ice Stream D's tributaries are coincident with "buckled" internal ice-sheet layers, most probably deformed by the processes responsible for enhanced ice flow. Between the tributaries well-preserved internal layers occur. The data reveal that no lateral migration of the ice-stream tributaries has occured recently. This is consistent with thermomechanical ice-flow modelling, which indicates that the flow of the Ice Stream D is controlled by a subglacial trough and is unaffected by changes to the flow of neighbouring Ice Stream C. © International Glaciological Society.