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Systematic climate model biases in the large-scale pattern of recent sea-surface temperature and sea-level pressure change
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  • Robert C Jnglin Wills,
  • Yue Dong,
  • Cristian Proistosecu,
  • Kyle C Armour,
  • David S Battisti
Robert C Jnglin Wills
University of Washington

Corresponding Author:[email protected]

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Yue Dong
Columbia University
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Cristian Proistosecu
University of Illinois
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Kyle C Armour
University of Washington
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David S Battisti
University of Washington
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Abstract

Observed surface temperature trends over recent decades are characterized by (i) intensified warming in the Indo-Pacific Warm Pool and slight cooling in the eastern equatorial Pacific, consistent with strengthening of the Walker circulation, and (ii) cooling in the Southern Ocean. In contrast, state-of-the-art coupled climate models generally project Walker circulation weakening, enhanced warming in the eastern equatorial Pacific, and warming in the Southern Ocean. Here we investigate the ability of 16 climate model large ensembles to reproduce observed sea-surface temperature and sea-level pressure trends over 1979-2020 through a combination of externally forced climate change and internal variability. We find large-scale differences between observed and modeled trends that are very unlikely (<5% probability) to occur due to internal variability as represented in models. Disparate trends are found even in regions with weak multi-decadal variability, suggesting that model biases in the transient response to anthropogenic forcing constitute part of the discrepancy.