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Evaluation of radiation scheme performance within chemistry climate models

Forster, PM, Fomichev, VI, Rozanov, E, Cagnazzo, C, Jonsson, AI, Langematz, U, Fomin, B, Iacono, MJ, Mayer, B, Mlawer, E, Myhre, G, Portmann, RW, Akiyoshi, H, Falaleeva, V, Gillett, N, Karpechko, A, Li, JN, Lemennais, P, Morgenstern, O, Oberlander, S, Sigmond, M and Shibata, K (2011) Evaluation of radiation scheme performance within chemistry climate models. Journal of Geophysical Research Atmospheres, 116. ISSN 0148-0227

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Abstract

This paper evaluates global mean radiatively important properties of chemistry climate models (CCMs). We evaluate stratospheric temperatures and their 1980-2000 trends, January clear sky irradiances, heating rates, and greenhouse gas radiative forcings from an offline comparison of CCM radiation codes with line-by-line models, and CCMs' representation of the solar cycle. CCM global mean temperatures and their change can give an indication of errors in radiative transfer codes and/or atmospheric composition. Biases in the global temperature climatology are generally small, although five out of 18 CCMs show biases in their climatology that likely indicate problems with their radiative transfer codes. Temperature trends also generally agree well with observations, although one model shows significant discrepancies that appear to be due to radiation errors. Heating rates and estimated temperature changes from CO2, ozone, and water vapor changes are generally well modeled. Other gases (N2O, CH4, and CFCs) have only played a minor role in stratospheric temperature change, but their heating rates have large fractional errors in many models. Models that do not account for variations in the spectrum of solar irradiance cannot properly simulate solar-induced variations in stratospheric temperature. The combined long-lived greenhouse gas global annual mean instantaneous net radiative forcing at the tropopause is within 30% of line-by-line models for all CCM radiation codes tested. Problems remain in simulating radiative forcing for stratospheric water vapor and ozone changes with errors between 3% and 200% compared to line by line models. The paper makes recommendations for CCM radiation code developers and future intercomparisons.

Item Type: Article
Copyright, Publisher and Additional Information: Reproduced in accordance with the publisher's self-archiving policy.
Keywords: general-circulation models, stratospheric water-vapor, by-line calculations, middle atmosphere, solar-radiation, impact, codes, ozone, parameterization, aerosols
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds)
Depositing User: Symplectic Publications
Date Deposited: 08 Sep 2011 11:50
Last Modified: 08 Jun 2014 21:07
Published Version: http://dx.doi.org/10.1029/2010JD015361
Status: Published
Publisher: American Geophysical Union
Identification Number: 10.1029/2010JD015361
URI: http://eprints.whiterose.ac.uk/id/eprint/43200

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