King George Island ice cap geometry updated with airborne GPR measurements

Ice geometry is a mandatory requirement for numerical modelling purposes. In this paper we present a consistent data set for the ice thickness, the bedrock topography and the ice surface topography of the King George Island ice cap (Arctowski Icefield and the adjacent central part). The newly data set is composed of groundbased and airborne Ground Penetrating Radar (GPR) and differential GPS (DGPS) measurements, obtained during several field campaigns. Blindow et al. (2010) already provided a comprehensive overview of the groundbased measurements carried out in the safely accessible area of the ice cap. The updated data set incorporates airborne measurements in the heavily crevassed coastal areas. Therefore, in this paper special attention is paid to the airborne measurements by addressing the used instrument, survey, and data processing in more detail. In particular, the inclusion of airborne GPR measurements with the 30 MHz BGR-P30-System developed at the Institute of Geophysics (University of Münster) completes the picture of the ice geometry substantially. The compiled digital elevation model of the bedrock shows a rough, highly variable topography with pronounced valleys, ridges, and troughs. Mean ice thickness is ~240 m, with a maximum value of ~400 m in the surveyed area. Noticeable are bounded areas in the bedrock topography below sea level where marine based ice exists. The provided data set is required as a basis for future monitoring attempts or as input for numerical modelling experiments. The data set is available from the PANGAEA database at doi:10.1594/PANGAEA.770567.