The objective of the Antarctic Firn Aquifer expedition is to verify the presence of firn aquifers on the Antarctic Ice Sheet by surveying two key sites on the Antarctic Peninsula: the Wilkins Ice Shelf and the southern George VI Ice Shelf. These field sites were identified using our mapping method and data from two satellite microwave instruments: a C-band radar scatterometer (EUMETSAT’s Advanced SCATterometer – ASCAT) and an L-band microwave radiometer (aboard NASA’s Soil Moisture Active Passive Satellite–SMAP). The longer wavelength of ASCAT and SMAP microwaves, and their sensitivity to the presence of liquid meltwater, allow them to see firn aquifers on ice sheets or ice shelves as deep as ~60 meters (200 feet). Over time, distinct patterns in the microwave signals can be used to distinguish firn aquifers from areas that do not store meltwater at depth.