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Recent studies have demonstrated that wideband microwave radiometers provide significant potential for profiling important subsurface polar firn characteristics necessary to understand the dynamics of the cryosphere and predict future changes in ice and snow coverage. Different frequencies within the wide spectra of radiometers result in different electromagnetic propagation losses and thus reveal characteristics at different depths in ice and snow. This paper, expanding on those investigations, explores the utilization of the Global Precipitation Measurement (GPM) constellation as a single wideband (6.93 GHz–91.655 GHz) spaceborne radiometer, covering the entire microwave spectrum from C-band to W-band, to profile subsurface properties of the Antarctic firn. Results of the initial analyses over Concordia and Vostok Stations in Antarctica indicate that GPM brightness temperature measurements provide critical information regarding the subsurface temperatures and physical properties of the firn from the surface down to several meters of depth. Considering the high spatiotemporal coverage of polar-orbiting spaceborne radiometers, these results are promising for future continent-level thermal and physical characterization of the Antarctic firn. 

Multi-frequency microwave radiometer measurements can reveal important subsurface characteristics of ice sheets such as internal temperature, density, grain size and ice thickness, which are critical to understand ice sheet dynamics. This study explores the sensitivity of electromagnetic radiation from ice sheets to these properties across the microwave spectrum, from L-band to W-band. The results indicate that (i) the maximum depth for which surface radiations provide information decreases from >2000 m in L-band to ~3 m in W-band, (ii) seasonal variations in internal temperatures are reflected mostly at frequencies in K a -band and above, (iii) impact of the geothermal heat flux can be observed mainly in L- and S-bands, and (iv) changes in density and grain size properties affect the electromagnetic penetration depth, thus, may influence surface emissions across the entire microwave spectrum.