Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures

Kevin Cowtan*, Zeke Hausfather, Ed Hawkins, Peter Jacobs, Michael E. Mann, Sonya K. Miller, Byron A. Steinman, Martin B. Stolpe, Robert G. Way

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The level of agreement between climate model simulations and observed surface temperature change is a topic of scientific and policy concern. While the Earth system continues to accumulate energy due to anthropogenic and other radiative forcings, estimates of recent surface temperature evolution fall at the lower end of climate model projections. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. Applying the methodology of the HadCRUT4 record to climate model temperature fields accounts for 38% of the discrepancy in trend between models and observations over the period 1975-2014.

Original languageEnglish
Pages (from-to)6526-6534
Number of pages9
JournalGeophysical Research Letters
Volume42
Issue number15
Early online date29 Jul 2015
DOIs
Publication statusPublished - 26 Aug 2015

Bibliographical note

© 2015, American Geophysical Union. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

Keywords

  • climate models
  • temperature record

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