Abstract

Two over-snow radar surveys were performed at the Antarctic Plateau, West Antarctica, by Centro de Estudios Científicos (CECs) in January 2014 and December 2014 respectively. We surveyed a combined total distance of approximately 2,200 km. The results of radar measurements at the multiple ice divide Institute Ice Stream, Pine Island and Minnesota glaciers are presented here. The radar was composed by two parts: 1) a coherent 155 MHz pulse-compression radar, with 20 MHz of bandwidth and 200 W of output power, for ice thickness detection, and 2) a fine resolution Frequency Modulated-Continuous Wave (FM-CW) radar, with a frequency range from 203 MHz to 1019 MHz, used for accumulation layers detection. The ice thickness at the divide is ~900 m, and the maximum ice thickness around the divide is ~2200 m. The fine resolution radar detected approximately 150 m of shallow layers at the divide, where the stratigraphy is clearly visible. Both radar outputs were combined to produce one radargram for each profile, with a processing to enhance isochrones visualization. A shallow firn core at the divide and 12 stakes were used to determine the accumulation-rate at this site. Additionally, accumulation-rate derived from the fine resolution radar was performed. The preliminary result indicates that the accumulation-rate is ~0.23 m of water equivalent per year at the divide.