Detection of a perennial firn aquifer within Nivlisen Ice Shelf, East Antarctica

Perennial Firn Aquifers (PFA’s) facilitate meltwater storage within an ice sheet’s firn layer. They have been extensively mapped across the Greenland Ice Sheet, largely using Operation Ice Bridge and Sentinel-1 data. However, in Antarctica, observations of PFA’s are limited to the Antarctic Peninsula, where the combination of high accumulation and ablation aids in the formation and insulation of extensive sub-surface meltwater reservoirs. On ice shelves, PFA’s have the potential to drive ice-shelf damage via hydrofracture, and it is therefore crucial that we have a better understanding of their presence beyond the Antarctic Peninsula.

 

To begin to improve our understanding for PFA’s elsewhere in Antarctica, we conduct a study on the Nivlisen Ice Shelf, an ice-shelf often characterised by extensive surface meltwater networks in Dronning Maud Land, East Antarctica. In addition to high rates of ablation, Nivlisen Ice Shelf also experiences high accumulation rates, making the ice-shelf a good candidate for the formation of PFAs. To investigate this theory, we utilise a method previously applied on the Greenland Ice Sheet, and exploit the low backscatter values returned in C-band synthetic aperture radar (SAR) data to detect potential PFA’s. C-band SAR data is obtained from Sentinel-1 and RADARSAT Constellation Mission (RCM), and is complemented with L-band SAR imagery. With both the NASA-ISRO Synthetic Aperture Radar (NISAR) and Copernicus ROSE-L satellites planned for future launches, we hope that our work will allow us to better understand the value of combined C- and L- band research for for studies of buried meltwater across both the Greenland and Antarctic Ice Sheets.