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Impact of Climate Drift on Twenty-First-Century Projection in a Coupled Atmospheric–Ocean General Circulation Model

Liang, Mao-Chang and Lin, Li-Ching and Tung, Ka-Kit and Yung, Yuk L. and Sun, Shan (2013) Impact of Climate Drift on Twenty-First-Century Projection in a Coupled Atmospheric–Ocean General Circulation Model. Journal of the Atmospheric Sciences, 70 (10). pp. 3321-3327. ISSN 0022-4928. http://resolver.caltech.edu/CaltechAUTHORS:20131105-152313847

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Abstract

Reducing climate drift in coupled atmosphere–ocean general circulation models (AOGCMs) usually requires 1000–2000 years of spinup, which has not been practical for every modeling group to do. For the purpose of evaluating the impact of climate drift, the authors have performed a multimillennium-long control run of the Goddard Institute for Space Studies model (GISS-EH) AOGCM and produced different twentieth-century historical simulations and subsequent twenty-first-century projections by branching off the control run at various stages of equilibration. The control run for this model is considered at quasi equilibration after a 1200-yr spinup from a cold start. The simulations that branched off different points after 1200 years are robust, in the sense that their ensemble means all produce the same future projection of warming, both in the global mean and in spatial detail. These robust projections differ from the one that was originally submitted to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4), which branched off a not-yet-equilibrated control run. The authors test various common postprocessing schemes in removing climate drift caused by a not-yet-equilibrated ocean initial state and find them to be ineffective, judging by the fact that they differ from each other and from the robust results that branched off an equilibrated control. The authors' results suggest that robust twenty-first-century projections of the forced response can be achieved by running climate simulations from an equilibrated ocean state, because memory of the different initial ocean state is lost in about 40 years if the forced run is started from a quasi-equilibrated state.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://journals.ametsoc.org/doi/abs/10.1175/JAS-D-13-0149.1PublisherArticle
http://dx.doi.org/10.1175/JAS-D-13-0149.1DOIArticle
Additional Information:© 2013 American Meteorological Society. Manuscript received 9 May 2013, in final form 25 June 2013. We thank editor Ming Cai for his detailed suggestions and two anonymous reviewers for their comments that helped focus the presentation. This work is supported in part by NSC Grant 101-2628-M-001-001-MY4 to Academia Sinica and its Grid Computing Center, KKT’s research by NSF Grants ATM 0808375 and DMS 0940342, and YLY’s by Caltech’s KISS program.
Group:Keck Institute for Space Studies
Funders:
Funding AgencyGrant Number
National Science Council (Taipei)101-2628-M-001-001-MY4
NSFATM-0808375
NSFDMS-0940342
Keck Institute for Space Studies (KISS)UNSPECIFIED
Subject Keywords:Climate models, Coupled models, Model comparison, Model evaluation/performance, Climate variability, Trends
Record Number:CaltechAUTHORS:20131105-152313847
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20131105-152313847
Official Citation: Liang, Mao-Chang, Li-Ching Lin, Ka-Kit Tung, Yuk L. Yung, Shan Sun, 2013: Impact of Climate Drift on Twenty-First-Century Projection in a Coupled Atmospheric–Ocean General Circulation Model. J. Atmos. Sci., 70, 3321–3327. doi: http://dx.doi.org/10.1175/JAS-D-13-0149.1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42258
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:06 Nov 2013 00:03
Last Modified:31 Oct 2017 18:20

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