De-tuning Albedo parameters in a coupled climate ice sheet model to simulate the North American ice sheet at the last glacial maximum

Gandy, N., Astfalck, L. C., Gregoire, L. J., Evanovich, R. F., Patterson, V. L., Sherriff-Tadano, S., Smith, R. S. ORCID: https://orcid.org/0000-0001-7479-7778, Williamson, D. and Rigby, R. (2023) De-tuning Albedo parameters in a coupled climate ice sheet model to simulate the North American ice sheet at the last glacial maximum. Journal of Geophysical Research: Earth Surface, 128 (8). e2023JF007250. ISSN 2169-9003 doi: 10.1029/2023JF007250

Abstract/Summary

The Last Glacial Maximum extent of the North American Ice Sheets is well constrained empirically but has proven to be challenging to simulate with coupled Climate-Ice Sheet models. Coupled Climate-Ice Sheet models are often too computationally expensive to sufficiently explore uncertainty in input parameters, and it is unlikely that values calibrated to reproduce modern ice sheets will reproduce the known extent of the ice at the Last Glacial Maximum. To address this, we run an ensemble with a coupled Climate-Ice Sheet model (FAMOUS-ice), simulating the final stages of growth of the last North American Ice Sheets' maximum extent. Using this large ensemble approach, we explore the influence of numerous uncertain ice sheet albedo, ice sheet dynamics, atmospheric, and oceanic parameters on the ice sheet extent. We find that ice sheet albedo parameters determine the majority of uncertainty when simulating the Last Glacial Maximum North American Ice Sheets. Importantly, different albedo parameters are needed to produce a good match to the Last Glacial Maximum North American Ice Sheets than have previously been used to model the contemporary Greenland Ice Sheet due to differences in cloud cover over ablation zones. Thus, calibrating coupled climate-ice sheet models on one ice sheet may produce strong biases when the model is applied to a new domain.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/112998
Identification Number/DOI	10.1029/2023JF007250
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Wiley
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