Publication:
A Spatial Evaluation of Arctic Sea Ice and Regional Limitations in CMIP6 Historical Simulations

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Authors
Watts, Matthew
Maslowski, Wiewslaw
Lee, Younjoo J.
Kinney, Jaclyn Clement
Osinski, Robert
Subjects
Arctic
Sea ice
Climate models
Error analysis
Model comparison
Regional models
Advisors
Date of Issue
2021-08
Date
Publisher
AMS
Language
Abstract
The Arctic sea ice response to a warming climate is assessed in a subset of models participating in phase 6 of the Coupled Model Intercomparison Project (CMIP6), using several metrics in comparison with satellite observations and results from the Pan-Arctic Ice Ocean Modeling and Assimilation System and the Regional Arctic System Model. Our study examines the historical representation of sea ice extent, volume, and thickness using spatial analysis metrics, such as the integrated ice edge error, Brier score, and spatial probability score. We find that the CMIP6 multimodel mean captures the mean annual cycle and 1979–2014 sea ice trends remarkably well. However, individual models experience a wide range of uncertainty in the spatial distribution of sea ice when compared against satellite measurements and reanalysis data. Our metrics expose common and individual regional model biases, which sea ice temporal analyses alone do not capture. We identify large ice edge and ice thickness errors in Arctic subregions, implying possible model specific limitations in or lack of representation of some key physical processes. We postulate that many of them could be related to the oceanic forcing, especially in the marginal and shelf seas, where seasonal sea ice changes are not adequately simulated. We therefore conclude that an individual model’s ability to represent the observed/reanalysis spatial distribution still remains a challenge. We propose the spatial analysis metrics as useful tools to diagnose model limitations, narrow down possible processes affecting them, and guide future model improvements critical to the representation and projections of Arctic climate change.
Type
Article
Description
17 USC 105 interim-entered record; under review.
The article of record as published may be found at http://dx.doi.org/10.1175/JCLI-D-20-0491.1
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
U.S. Navy
Department of Energy (DOE)
Regional and Global Model Analysis (RGMA)
Office of Naval Research (ONR)
Arctic and Global Prediction (AGP)
National Science Foundation (NSF)
Arctic System Science (ARCSS)
Ministry of Science and Higher Education in Poland
Funder
DOE: 89243019SSC0036
DESC0014117
ONR: N0001418WX00364
NSF: IAA1417888
IAA1603602
Format
22 p.
Citation
Watts, Matthew, et al. "A spatial evaluation of Arctic sea ice and regional limitations in CMIP6 historical simulations." Journal of Climate 34.15 (2021): 6399-6420.
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States
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