Mapping Firn Saturation Over Greenland Using NASA’s Soil Moisture Active Passive Satellite

Mapping the spatial extent of recently identified englacial hydrological features (i.e., ice slabs and perennial firn aquifers) formed by meters-thick water-saturated layers over percolation facies Greenland Ice Sheet using L-band microwave radiometry has been demonstrated. However, these initial maps are binary, do not provide a parameter to estimate variability in thickness volumetric fraction meltwater stored within pore space. Here, we exploit enhanced-resolution vertical-polarization brightness temperature ($T_{V}^{B}$) imagery (2015–2019) generated observations collected NASA’s Soil Moisture Active Passive (SMAP) satellite simple two-layer model. We map via “firn saturation” parameter, interpret our results together with slab aquifer extents, estimates snow accumulation simulated Regional Atmospheric Climate Model (RACMOp2.3), airborne radar surveys Operation IceBridge (OIB) campaigns. find that variable saturation values mapped lower areas western, northern, northeastern Greenland, where is colder seasonally refreeze as solid-ice. Higher higher southeastern, southern, northwestern near melting point, exist. Our have implications for identifying expansive reservoirs store significant volumes locations vulnerable meltwater-induced hydrofracturing accelerated outlet glacier flow year-round.