Monitoring Ice Sheet Melt and Refreeze Using Active Microwave Measurements

The time-varying areal extent and duration of surface melt on ice sheets are important parameters for climate and cryosphere research and key indicators of climate change in polar regions. To evaluate snowmelt dynamics and melting/refreezing processes in Greenland and Antarctica, we developed and implemented an algorithm for generating time-series of surface melt extent and melt phases (dry, wet refreezing) based on the analysis of continuous time series of C-band active microwave satellite data. Our results, based on METOP ASCAT scatterometer and Sentinel-1 SAR data, demonstrate the excellent capability of these missions for operational monitoring of snowmelt areas, providing a consistent climate data record on the presence of liquid water in snow and firn areas of Greenland and Antarctica for studying surface melt processes and ice sheet mass loss.