CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols

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 simu...

Full description

Saved in:
Bibliographic Details
Main Authors: Petr Chylek, Chris Folland, James D. Klett, Manvendra K. Dubey
Format: Article
Language:English
Published: Wiley 2020-02-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2020GL087047
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850135365164204032
author Petr Chylek
Chris Folland
James D. Klett
Manvendra K. Dubey
author_facet Petr Chylek
Chris Folland
James D. Klett
Manvendra K. Dubey
author_sort Petr Chylek
collection DOAJ
description 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.
format Article
id doaj-art-e3c5c97dc9a648f8ab441e4e67b97927
institution OA Journals
issn 0094-8276
1944-8007
language English
publishDate 2020-02-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-e3c5c97dc9a648f8ab441e4e67b979272025-08-20T02:31:27ZengWileyGeophysical Research Letters0094-82761944-80072020-02-01473n/an/a10.1029/2020GL087047CMIP5 Climate Models Overestimate Cooling by Volcanic AerosolsPetr Chylek0Chris Folland1James D. Klett2Manvendra K. Dubey3Earth and Environmental Sciences Los Alamos National Laboratory Los Alamos New MexicoSchool of Environmental Sciences University of East Anglia Norwich UKPAR Associates Las Cruces New MexicoEarth and Environmental Sciences Los Alamos National Laboratory Los Alamos New MexicoAbstract 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.https://doi.org/10.1029/2020GL087047climate modelsvolcanic aerosolsregression analysisAMOpredictorsradiative forcing
spellingShingle Petr Chylek
Chris Folland
James D. Klett
Manvendra K. Dubey
CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols
Geophysical Research Letters
climate models
volcanic aerosols
regression analysis
AMO
predictors
radiative forcing
title CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols
title_full CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols
title_fullStr CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols
title_full_unstemmed CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols
title_short CMIP5 Climate Models Overestimate Cooling by Volcanic Aerosols
title_sort cmip5 climate models overestimate cooling by volcanic aerosols
topic climate models
volcanic aerosols
regression analysis
AMO
predictors
radiative forcing
url https://doi.org/10.1029/2020GL087047
work_keys_str_mv AT petrchylek cmip5climatemodelsoverestimatecoolingbyvolcanicaerosols
AT chrisfolland cmip5climatemodelsoverestimatecoolingbyvolcanicaerosols
AT jamesdklett cmip5climatemodelsoverestimatecoolingbyvolcanicaerosols
AT manvendrakdubey cmip5climatemodelsoverestimatecoolingbyvolcanicaerosols