Uncertainty in East Antarctic firn thickness constrained using a model ensemble approach

Mass balance assessments of the East Antarctic ice sheet (EAIS) are highly sensitive to changes in firn thickness, causing substantial disagreement in estimates of its contribution to sea‐level. To better constrain the uncertainty in recent firn thickness changes, we develop an ensemble of 54 model...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Verjans, Vincent, Leeson, Amber, McMillan, Mal, Stevens, Max, van Wessem, Jan Melchior, van de Berg, Willem Jan, van den Broeke, Michiel, Kittel, Christoph, Amory, Charles, Fettweis, Xavier, Hansen, Nicolaj, Boberg, Fredrik, Mottram, Ruth
Format: Article in Journal/Newspaper
Language:unknown
Published: 2021
Subjects:
Antarctic
East Antarctic Ice Sheet
Antarc*
Ice Sheet
Online Access:https://eprints.lancs.ac.uk/id/eprint/152942/
https://doi.org/10.1029/2020GL092060
Description
Summary:Mass balance assessments of the East Antarctic ice sheet (EAIS) are highly sensitive to changes in firn thickness, causing substantial disagreement in estimates of its contribution to sea‐level. To better constrain the uncertainty in recent firn thickness changes, we develop an ensemble of 54 model scenarios of firn evolution between 1992‐2017. Using statistical emulation of firn‐densification models, we quantify the impact of firn compaction formulation, differing climatic forcing, and surface snow density on firn thickness evolution. At basin scales, the ensemble uncertainty in firn thickness change ranges between 0.2–1.0 cm yr‐1 (15–300% relative uncertainty), with the choice of climate forcing having the largest influence on the spread. Our results show the regions of the ice sheet where unexplained discrepancies exist between observed elevation changes and an extensive set of modelled firn thickness changes estimates, marking an important step towards more accurately constraining ice sheet mass balance.

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