Reconciling Solid Earth and Ice Sheet Temperature Estimates for Greenland #
Abstract #
In our project, we plan to analyse the thermal state of the Greenland ice sheet and lithosphere with a focus on reconciling temperature estimates for the two geospaces. Considerable differences exist in existing models and we first carry out robust geostatistical analysis of the uncertainties of both geothermal observations and ice temperature profiles. These point/profile-wise estimates will be first linked on a local scale by using auxiliary geophysical data (radar, gravity, magnetics) from airborne surveys in order to verify the compatibility of the estimates. In the second step, we will extend the analysis to the entire icesheet using temperature estimates from the SMOS satellite mission and all available geophysical data to describe both the thermal state and the geological conditions at the base of the ice-top bed interface. We will also extend our analysis to assess possibility by using a potentially improved ice temperature model, which is one of the objectives of the CryoRad satellite mission proposed as one candidate for the Earth Explorer Call 12 by the European Space Agency. All thermal models will be tested as input in models of the ice-sheet dynamics with a focus on clarifying the role of a thermal anomaly at the onset of the Northeast Greenland ice stream.
Introduction #
The melting of the Greenland ice sheet has been one of the largest sources of sea-level rise since the early 2000s. Despite the mass loss of more than 275 Gt/a, the driving components and their feedback mechanism are still not completely understood, and large uncertainties remain a.o. with respect to sub-glacial conditions. For example, sub-ice geology or geothermal heat flow directly affect the basal conditions of the ice sheets and are essential to understand how Solid Earth and Cryosphere processes are coupled.
Background #
Funded by the German Reseach Foundation running from 2024-2027.
Objectives #
The main objective of the project is to reconcile temperature and heat flow estimates from in-situ measurements with thermal models of the lithosphere and ice-sheets for Greenland. This analysis is done by coupling an ice temperature retrieval scheme with Solid Earth models while considering basal melt-water production. A secondary objective is to study the scalability on
results for line data and observation points with regional models. Therefore, available ice profiles and GHF observations are studied before the analysis is extended to use data from the SMOS satellite mission. All these estimates will be evaluated by modelling the evolution on the Greenland ice sheet in order to verify the role of regional and local thermal anomalies.
Conclusions #
Freienstein, J., Szwillus, W., Zimmer, M., & Ebbing, J. (2025). Learning from Finland: Variability of subglacial heat flow
in Greenland explored from geological units and radiogenic heat production. Journal of Geophysical Research: Solid
Earth, 130, e2025JB031545. https://doi.org/10.1029/2025JB031545