The Greenland Firn Aquifer Temporal Variability and Spatial Extent from Airborne Radar.

Abstract:

The Greenland firn aquifer stores liquid water year-round in the subsurface pore space predominantly in the southeast region of the ice sheet where accumulation and melt rates are high. We use airborne radar from NASA’s Operation IceBridge (OIB) and the University of Kansas’s Center for Remote Sensing of the Ice Sheets (CReSIS) to map the spatial and temporal variability of the aquifer. The extent of the aquifer is mapped each year with OIB flights beginning in 2011 through 2015. Different coverage provided by the flight lines each year has now allowed a more comprehensive view of the aquifer extent. Some annually repeated lines indicate changes in the aquifer extent and depth below the surface. Loss of ice/bedrock interface returns in archival radar depth sounding data from the early 1990’s implies the aquifer was in place at that time. Ground-based measurements from field campaigns in 2011, 2013, 2014, and 2015 verify the radar detection and supply additional information on water thickness, volume, and flow.