Applicant

Dr. Ole Zeising
Alfred-Wegener-Institut
Helmholtz-Zentrum für Polar- und Meeresforschung
Fachbereich Geowissenschaften Sektion Glaziologie
Am Alten Hafen 26
27568 Bremerhaven

Project description

This project aims to improve the determination of melt rates beneath Antarctic ice shelves from satellite remote sensing through systematic validation with ground-based radar observations. Ice shelves are the floating extensions of the Antarctic Ice Sheet and play a crucial role in stabilizing the grounded ice. Increasing basal melt rates, driven by ocean heat flux, threaten the stability of these ice shelves. Their thinning or collapse can accelerate the flow of ice into the ocean and thus contribute to global sea-level rise. Observations of basal melt rates are essential for understanding how the Antarctic Ice Sheet interacts with the surrounding ocean and how both may respond to a warming climate. Satellite remote sensing provides the only means to monitor basal melting continuously at a continental scale. These estimates are derived from changes in surface elevation measured by satellite altimetry, combined with additional satellite datasets and numerical models. However, this approach is affected by significant uncertainties, for example due to changes in snow and firn properties or assumptions in the applied models. To better quantify these uncertainties and improve the accuracy of satellite-based melt-rate estimates, I will systematically validate them with ground-based measurements. These in-situ observations are obtained using an Autonomous phase-sensitive Radio-Echo Sounder (ApRES), a radar system that precisely tracks vertical movements within the ice and provides highly accurate basal melt rates. I will reprocess existing ApRES datasets from 14 Antarctic ice shelves to generate a comprehensive consistent reference dataset. This dataset will include not only basal melt rates, but also intermediate products such as ice-shelf thickness change, surface accumulation and firn densification, and vertical strain. By comparing these in-situ observations with satellite-derived products, I will identify the dominant sources of uncertainty and assess the reliability of current remote-sensing products. My ultimate goal is to combine the best validated satellite datasets with a new developed surface-elevation-change product to produce an improved estimate of Antarctic ice-shelf basal melt rates. The outcome will be a robust framework for evaluating satellite observations and for integrating ground-based and remote-sensing data. This will advance our ability to monitor the stability of Antarctic ice shelves and to understand the ongoing changes at the interface between the ice sheet and the ocean.

DFG Programme Infrastructure Priority Programmes

Term since 2026