A pole of ignorance is filled: bed topography of the Recovery Region, East Antarctica

The Recovery Region, consisting of Recovery, Bailey and Slessor Glaciers, discharges 5 % of the total fresh water outflow of Antarctica into the Filchner Ice Shelf, which is subject to extensive sub-shelf melting under ongoing climate change. Several active subglacial lakes have been identified in the Recovery Region from satellite data, indicating the existence of a dynamic subglacial hydrologic system. Nevertheless, no direct ice thickness data were available within 200 km in this region, which was identified as one of two `poles of ignorance' by BEDMAP2. In 2013 an extensive survey was carried out in the Recovery Region within the IceGrav project. Here, we present new bed topography data obtained from radar measurements, which indicate strong topographic controls on glacier flow. The deep trough of the Recovery Glacier reaches up to 2200 m below sea level, and extends 800 km inland from the current grounding line. Slessor Glacier shows a deep area, 1600 m below sea level, about 400 km inland from the grounding line. The upstream area of Slessor Glacier is topographically controlled on one side; however, no clear topographic boundary can be identified on the other side, towards the Bailey catchment area. Our findings refine the knowledge of the Recovery Region and provide a more precise understanding of past ice dynamics of this region.