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Radiative Forcing in the ACCMIP Historical and Future Climate SimulationsA primary goal of the Atmospheric Chemistry and Climate Model IntercomparisonProject (ACCMIP) was to characterize the short-lived drivers of preindustrial to 2100climate change in the current generation of climate models. Here we evaluate historicaland 5 future radiative forcing in the 10 ACCMIP models that included aerosols, 8 of whichalso participated in the Coupled Model Intercomparison Project phase 5 (CMIP5).The models generally reproduce present-day climatological total aerosol opticaldepth (AOD) relatively well. components to this total, however, and most appear to underestimate AOD over East10 Asia. The models generally capture 1980-2000 AOD trends fairly well, though theyunderpredict AOD increases over the YellowEastern Sea. They appear to strongly underestimate absorbing AOD, especially in East Asia, South and Southeast Asia, SouthAmerica and Southern Hemisphere Africa.We examined both the conventional direct radiative forcing at the tropopause (RF) and the forcing including rapid adjustments (adjusted forcing AF, including direct andindirect effects). The models calculated all aerosol all-sky 1850 to 2000 global meanannual average RF ranges from 0.06 to 0.49 W m(sup -2), with a mean of 0.26 W m(sup -2) and a median of 0.27 W m(sup -2. Adjusting for missing aerosol components in some modelsbrings the range to 0.12 to 0.62W m(sup -2), with a mean of 0.39W m(sup -2). Screen20ing the models based on their ability to capture spatial patterns and magnitudes ofAOD and AOD trends yields a quality-controlled mean of 0.42W m(sup -2) and range of0.33 to 0.50 W m(sup -2) (accounting for missing components). The CMIP5 subset of ACCMIPmodels spans 0.06 to 0.49W m(sup -2), suggesting some CMIP5 simulations likelyhave too little aerosol RF. A substantial, but not well quantified, contribution to histori25cal aerosol RF may come from climate feedbacks (35 to 58). The mean aerosol AF during this period is 1.12W m(sup -2) (median value 1.16W m(sup -2), range 0.72 to1.44W m(sup -2), indicating that adjustments to aerosols, which include cloud, water vaporand temperature, lead to stronger forcing than the aerosol direct RF.
Document ID
20140009211
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Shindell, Drew Todd
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Lamarque, J.-F.
(National Center for Atmospheric Research Boulder, CO, United States)
Schulz, M.
(Norwegian Meteorological Inst. Oslo, Norway)
Flanner, M.
(Michigan Univ. Ann Arbor, MI, United States)
Jiao, C.
(Michigan Univ. Ann Arbor, MI, United States)
Chin, M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Young, P. J.
(Colorado Univ. Boulder, CO, United States)
Lee, Y. H.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Rotstayn, L.
(Commonwealth Scientific and Industrial Research Organization Alice Springs, Australia)
Mahowald, N.
(Cornell Univ. Ithaca, NY, United States)
Milly, G.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Faluvegi, G.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Balkanski, Y.
(Institut Pierre-Simon Laplace (IPSL) France)
Collins, W. J.
(Met Office (Meteorological Office) Devon, United Kingdom)
Conley, A. J.
(National Center for Atmospheric Research Boulder, CO, United States)
Dalsoren, S.
(Center for International Climate and Environmental Research Oslo, Norway)
Easter, R.
(Pacific Northwest National Lab. Richland, WA, United States)
Ghan, S.
(Pacific Northwest National Lab. Richland, WA, United States)
Horowitz, L.
(Princeton Univ. NJ, United States)
Liu, X.
(Pacific Northwest National Lab. Richland, WA, United States)
Myhre, G.
(Center for International Climate and Environmental Research Oslo, Norway)
Nagashima, T.
(National Inst. for Environmental Studies Ibaraki, Japan)
Naik, V.
(Princeton Univ. NJ, United States)
Rumbold, S. T.
(Met Office (Meteorological Office) Devon, United Kingdom)
Skeie, R.
(Center for International Climate and Environmental Research Oslo, Norway)
Voulgarakis, A.
(Imperial Coll. of London London, United Kingdom)
Date Acquired
July 16, 2014
Publication Date
March 15, 2013
Publication Information
Publication: Atmospheric Chemistry and Physics
Publisher: Copernicus Publications
Volume: 13
Issue: 6
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN6089
Funding Number(s)
CONTRACT_GRANT: DE-AC06-76RLO 1830
CONTRACT_GRANT: NNX10AU63A
WBS: WBS 281945.02.31.02.52
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Climate Models
Radio Frequencies
Aerosols
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