Zelinka, MD, Klein, SA, Taylor, KE et al. (4 more authors) (2013) Contributions of different cloud types to feedbacks and rapid adjustments in CMIP5. Journal of Climate, 26 (14). 5007 - 5027. ISSN 0894-8755
Abstract
Using five climate model simulations of the response to an abrupt quadrupling of CO2, the authors perform the first simultaneous model intercomparison of cloud feedbacks and rapid radiative adjustments with cloud masking effects removed, partitioned among changes in cloud types and gross cloud properties. Upon CO2 quadrupling, clouds exhibit a rapid reduction in fractional coverage, cloud-top pressure, and optical depth, with each contributing equally to a 1.1 W m22 net cloud radiative adjustment, primarily from shortwave radiation. Rapid reductions in midlevel clouds and optically thick clouds are important in reducing planetary albedo in every model. As the planet warms, clouds become fewer, higher, and thicker, and global mean net cloud feedback is positive in all but onemodel and results primarily fromincreased trapping of longwave radiation. As was true for earliermodels, high cloud changes are the largest contributor to intermodel spread in longwave and shortwave cloud feedbacks, but low cloud changes are the largest contributor to the mean and spread in net cloud feedback. The importance of the negative optical depth feedback relative to the amount feedback at high latitudes is even more marked than in earlier models. The authors show that the negative longwave cloud adjustment inferred in previous studies is primarily caused by a 1.3 W m22 cloud masking of CO2 forcing. Properly accounting for cloudmasking increases net cloud feedback by 0.3 W m22 K21,whereas accounting for rapid adjustments reduces by 0.14 W m22 K21 the ensemble mean net cloud feedback through a combination of smaller positive cloud amount and altitude feedbacks and larger negative optical depth feedbacks.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © Copyright 2013 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or copyrights@ametsoc.org. |
Keywords: | Climate model simulations; Cloud feedbacks; Cloud properties; Cloud top pressure; Long-wave radiation; Rapid reduction; Short-wave radiation; Simultaneous model |
Dates: |
|
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: | 28 Jan 2014 10:56 |
Last Modified: | 16 Nov 2016 01:11 |
Published Version: | http://dx.doi.org/10.1175/JCLI-D-12-00555.1 |
Status: | Published |
Publisher: | American Meteorological Society |
Identification Number: | 10.1175/JCLI-D-12-00555.1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:77407 |