Netherlands Polar Data Center

Summary

A remarkable recent discovery is that of a huge (~70,000 km2) semi-permanent liquid water body in the firn layer of the Greenland ice sheet, named the perennial firn aquifer (PFA). The PFA has been traced by airborne and ground-based radar, and shown to exist mainly in the south-eastern Greenland ice sheet at elevations between 500 and 2100 m asl and in isolated pockets in the south-western ice sheet. The current hypothesis for the formation of a PFA is that it requires a rare combination of high melt rate, recharging the PFA in summer, and high accumulation rate, providing pore space and insulating the liquid water from the cold winter atmosphere. This storage of meltwater significantly impacts the (basal) hydrology of the ice sheet, by continuously releasing liquid water at the firn-ice interface and into crevasses. While it is currently being investigated how voluminous the Greenland PFA is, and whether it is a permanent or a transient feature, the question has arisen whether PFAs can also exist in the Antarctic ice sheet (AIS). That is the topic of the research proposed here. The quest for Antarctic PFAs is planned to take place along two tracks: our US collaborators will investigate airborne and satellite radar data to see whether obervational evidence can be found for the existence of PFAs in the AIS. At the same time, we propose to use a high-resolution regional atmospheric climate model to force two different snow models, to predict and explain the occurrence of PFAs in Antarctica.

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