Satellite Mapping of the Extent and Physical Characteristics of an Expansive Perennial Firn Aquifer in the Wilkins Ice Shelf, Antarctic Peninsula

We use enhanced-resolution L-band radar backscatter and brightness temperature image time series generated from observations collected by NASA’s Soil Moisture Active Passive (SMAP) mission to map the extent and physical characteristics of an expansive perennial firn aquifer recently identified in the Wilkins Ice Shelf, Antarctic Peninsula. Empirical algorithms to map extent are derived from a continuous logistic model. Distinct physical characteristics of the firn overlying the perennial firn aquifer are distinguished using images of the slope in radar backscatter versus incidence angle. An inverted two-layer L-band brightness temperature model parameterized by the optical thickness is used to map seasonal firn saturation. Our results demonstrate the potential for using low-frequency L-band satellite microwave missions to map large englacial meltwater reservoirs in the firn of Antarctic ice shelves that may trigger hydrofracture and ice shelf instability year-round.