Remapping of Greenland ice sheet surface mass balance anomalies for large ensemble sea-level change projections

• Published in: The Cryosphere
• Main Authors: Goelzer, H., Noël, Brice, Edwards, T., Fettweis, Xavier, Gregory, J., Lipscomb, W., van de Wal, R., van den Broeke, M.
• Other Authors: Sphères - SPHERES
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Group 2020
• Subjects: Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Greenland; Ice Sheet; The Cryosphere
• Online Access: https://orbi.uliege.be/handle/2268/247935; https://orbi.uliege.be/bitstream/2268/247935/1/tc-14-1747-2020.pdf; https://doi.org/10.5194/tc-14-1747-2020

peer reviewed Future sea-level change projections with process-based stand-alone ice sheet models are typically driven with surface mass balance (SMB) forcing derived from climate models. In this work we address the problems arising from a mismatch of the modelled ice sheet geometry with the geometry used by the climate model. We present a method for applying SMB forcing from climate models to a wide range of Greenland ice sheet models with varying and temporally evolving geometries. In order to achieve that, we translate a given SMB anomaly field as a function of absolute location to a function of surface elevation for 25 regional drainage basins, which can then be applied to different modelled ice sheet geometries. The key feature of the approach is the non-locality of this remapping process. The method reproduces the original forcing data closely when remapped to the original geometry. When remapped to different modelled geometries it produces a physically meaningful forcing with smooth and continuous SMB anomalies across basin divides. The method considerably reduces non-physical biases that would arise by applying the SMB anomaly derived for the climate model geometry directly to a large range of modelled ice sheet model geometries.