Exceptionally high Geothermal heat flux needed to sustain the Northeast Greenland Ice Stream
Abstract
The Northeast Greenland Ice Stream (NEGIS) is an important feature to capture in ice sheet models, when assessing the potential future contribution of Greenland to sea level rise. NEGIS displays fast flow further inland than any other ice stream in Greenland, and is suggested to be initiated by a geothermal heat flux anomaly at the head of the ice stream. This fast upstream velocity can only be reproduced in ice sheet models by inferring basal conditions using surface velocity observations. However, inversion masks all unknown information at the bed and keeps basal friction constant in time. We aim to represent NEGIS in the Ice Sheet System Model (ISSM) where ice dynamics are coupled to a subglacial hydrology model, without inverting for basal drag. We find that frictional heat from present day velocity, combined with geothermal heat flux maps are not sufficient to sustain the high velocity observed at the head of NEGIS. However, by including a geothermal heat flux anomaly of 970 mW/m2 (as suggested by Fahnestock et al. 2001) we successfully capture the observed characteristic velocity pattern of NEGIS.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C51C1299S
- Keywords:
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- 0726 Ice sheets;
- CRYOSPHERE;
- 0774 Dynamics;
- CRYOSPHERE;
- 0776 Glaciology;
- CRYOSPHERE;
- 0798 Modeling;
- CRYOSPHERE