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Observed Antarctic sea ice expansion reproduced in a climate model after correcting biases in sea ice drift velocity

Sun, Shantong and Eisenman, Ian (2021) Observed Antarctic sea ice expansion reproduced in a climate model after correcting biases in sea ice drift velocity. Nature Communications, 12 . Art. No. 1060. ISSN 2041-1723.

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The Antarctic sea ice area expanded significantly during 1979–2015. This is at odds with state-of-the-art climate models, which typically simulate a receding Antarctic sea ice cover in response to increasing greenhouse forcing. Here, we investigate the hypothesis that this discrepancy between models and observations occurs due to simulation biases in the sea ice drift velocity. As a control we use the Community Earth System Model (CESM) Large Ensemble, which has 40 realizations of past and future climate change that all undergo Antarctic sea ice retreat during recent decades. We modify CESM to replace the simulated sea ice velocity field with a satellite-derived estimate of the observed sea ice motion, and we simulate 3 realizations of recent climate change. We find that the Antarctic sea ice expands in all 3 of these realizations, with the simulated spatial structure of the expansion bearing resemblance to observations. The results suggest that the reason CESM has failed to capture the observed Antarctic sea ice expansion is due to simulation biases in the sea ice drift velocity, implying that an improved representation of sea ice motion is crucial for more accurate sea ice projections.

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URLURL TypeDescription ItemCode
Sun, Shantong0000-0002-6932-5589
Eisenman, Ian0000-0003-0190-2869
Additional Information:© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit Received 17 June 2020; Accepted 25 January 2021; Published 16 February 2021. Without implying their endorsement, we thank Ed Blanchard-Wrigglesworth, Till J.W. Wagner, Paul Holland, and Elizabeth Hunke for helpful comments and discussions. This work was supported by National Science Foundation Grant OPP-1643445. Data availability: Model simulation output fields that support the findings of this study are available in figshare at Code availability: The CESM code modifications used in this study can be accessed at Author Contributions: I.E. and S.S. designed the simulations and analysis, S.S. carried out the simulations and analysis, and S.S. and I.E. wrote the manuscript. The authors declare no competing interests. Peer review information: Nature Communications thanks Karen Smith and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
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Subject Keywords:Climate change; Cryospheric science
Record Number:CaltechAUTHORS:20210216-134914202
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Official Citation:Sun, S., Eisenman, I. Observed Antarctic sea ice expansion reproduced in a climate model after correcting biases in sea ice drift velocity. Nat Commun 12, 1060 (2021).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108070
Deposited By: Tony Diaz
Deposited On:16 Feb 2021 22:32
Last Modified:16 Feb 2021 22:32

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