Project description
Estimating Greenland’s past, present and future mass balance
The Greenland ice sheet and its outlying ice caps are losing mass at accelerating rates. An estimated 60 % of this mass loss is attributed to meltwater running off the flanks of the ice sheet. Any shift in the runoff limit can modify mass loss and subsequent sea level rise. The EU-funded CASSANDRA project will explore the runoff limit as a powerful modulator of Greenland mass balance, tracking it over the full satellite era using remote sensing archives. These time series of the runoff limit are complemented by detailed field measurements. The findings will be used to build firn hydrology models that can be applied to reconcile estimates of Greenland’s past, present and future mass balance.
Objective
Meltwater running off the flanks of the Greenland ice sheet contributes roughly 60% to its mass loss, the rest being due to calving. Only meltwater originating from below the elevation of the runoff limit leaves the ice sheet, contributing to mass loss; melt at higher elevations refreezes in the porous firn and does not drive mass loss. Therefore any shift in the runoff limit modifies mass loss and subsequent sea level rise. New evidence shows surface runoff at increasingly high elevations, outpacing the rate at which the equilibrium line elevation rises. This research proposal focuses on the runoff limit as a powerful yet poorly understood modulator of Greenland mass balance. We will track the runoff limit over the full satellite era using two of the largest and oldest remote sensing archives, Landsat and the Advanced Very High Resolution Radiometer (AVHRR). We will establish time series of the runoff limit for all regions of Greenland to identify the mechanisms driving fluctuations in the runoff limit. This newly gained process understanding and a wealth of in-situ measurements will then be used to build firn hydrology models capable of simulating runoff and the associated runoff limit over time. Eventually, the firn hydrology models will be applied to reconcile estimates of Greenland past, present and future mass balance. Covering the entire satellite era and all of Greenland, the focus on the runoff limit will constitute a paradigm shift leading to major advance in our understanding of how vulnerable the surface of the ice sheet reacts to climate change and how the changing surface impacts runoff and thus Greenland's role in the global sea level budget.
Fields of science
- natural sciencesearth and related environmental scienceshydrology
- engineering and technologymechanical engineeringvehicle engineeringaerospace engineeringsatellite technology
- engineering and technologyenvironmental engineeringremote sensing
- natural sciencesearth and related environmental sciencesatmospheric sciencesclimatologyclimatic changes
Keywords
Programme(s)
Funding Scheme
ERC-COG - Consolidator GrantHost institution
1700 Fribourg
Switzerland