CMIP5 climate models overestimate cooling by volcanic aerosols

Chylek, Petr and Folland, Chris and Klett, James D. and Dubey, Manvendra K. (2020) CMIP5 climate models overestimate cooling by volcanic aerosols. Geophysical Research Letters, 47. ISSN 0094-8276


Abstract

We compare projections of the observed hemispherical mean surface temperature (HadCRUT4.6.0.0) and the ensemble mean of CMIP5 climate models' simulations on a set of standard regression model forcing variables. We find that the volcanic aerosol regression coefficients of the CMIP5 simulations are consistently significantly larger (by 40–49%) than the volcanic aerosol coefficients of the observed temperature. The probability that the observed differences are caused just by chance is much less than 0.01. The overestimate is due to the climate models' response to volcanic aerosol radiative forcing. The largest overestimate occurs in the winter season of each hemisphere. We hypothesize that the models' parameterization of aerosol‐cloud interactions within ice and mixed phase clouds is a likely source of this discrepancy. Furthermore, the models significantly underestimate the effect of solar variability on temperature for both hemispheres.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Applied Climate Sciences (1 Aug 2018 -)
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Applied Climate Sciences (1 Aug 2018 -)
Date Deposited: 19 Feb 2020 02:13
Last Modified: 08 May 2020 02:42
Uncontrolled Keywords: volcanic aerosols, climate models
Fields of Research (2008): 04 Earth Sciences > 0401 Atmospheric Sciences > 040104 Climate Change Processes
Fields of Research (2020): 37 EARTH SCIENCES > 3702 Climate change science > 370201 Climate change processes
Identification Number or DOI: https://doi.org/10.1029/2020GL087047
URI: http://eprints.usq.edu.au/id/eprint/38246

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