Indian Ocean SST, evaporation, and precipitation during the South Asian summer monsoon in IPCC-AR4 coupled simulations
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The veracity of modeled air–sea interactions in the Indian Ocean during the South Asian summer monsoon is examined. Representative simulations of the twentieth century climate, produced by coupled general circulation models as part of the Intergovernmental Panel on Climate Change Fourth Assessment Report, are the analysis targets along with observational data. The analysis shows the presence of large systematic biases in coupled simulations of boreal summer precipitation, evaporation, and sea surface temperature (SST) in the Indian Ocean, often exceeding 50% of the climatological values. Many of the biases are pervasive, being common to most simulations. The representation of air–sea interactions is also compromised. Coupled models tend to emphasize local forcing in the Indian Ocean as reflected by their large precipitation–SST correlations, at odds with the weak links in observations which suggest the importance of non-local controls. The evaporation–SST correlations are also differently represented, indicating atmospheric control on SST in some models and SST control on evaporation in others. The Indian monsoon rainfall–SST links are also misrepresented: the former is essentially uncorrelated with antecedent and contemporaneous Indian Ocean SSTs in nature, but not so in most of the simulations. Overall, coupled models are found deficient in portraying local and non-local air–sea interactions in the Indian Ocean during boreal summer. In our opinion, current models cannot provide durable insights on regional climate feedbacks nor credible projections of regional hydroclimate variability and change, should these involve ocean–atmosphere interactions in the Indian basin.
KeywordsCoupled models South Asian monsoon Air–sea interactions Precipitation
The authors acknowledge NOAA and NSF support through CPPA-NA17EC1483 and ATM-0649666 grants.
- Annamalai H, Murtugudde R (2004) Role of the Indian Ocean in regional climate variability. In earth’s climate: the ocean–atmosphere interaction. Geophys Monograph Series 147:213–246Google Scholar
- Chandrasekar A, Kitoh A (1998) Impact of localized sea surface temperature anomalies over the equatorial Indian Ocean on the Indian summer monsoon. J Meteorol Soc Jpn 76:841–853Google Scholar
- Covey C, AchutaRao KM, Lambert SJ, Taylor KE (2000) Intercomparison of present and future climates simulated by coupled ocean–atmosphere GCMs. PCMDI report no 66. Program for Climate model diagnosis and intercomparison, Lawrence Livermore National Laboratory. University of California, LivermoreGoogle Scholar
- Delworth TL, Broccoli AJ, Rosati A, Stouffer RJ, Balaji V, Beesley JA, Cooke WF, Dixon KW, Dunne J, Dunne KA, Durachta JW, Findell KL, Ginoux P, Gnanadesikan A, Gordon CT, Griffies SM, Gudgel R, Harrison MJ, Held IM, Hemler RS, Horowitz LW, Klein SA, Knutson TR, Kushner PJ, Langenhorst AR, Lee H-C, Lin S-J, Lu J, Malyshev SL, Milly PCD, Ramaswamy V, Russell J, Schwarzkopf MD, Shevliakova E, Sirutis JJ, Spelman MJ, Stern WF, Winton M, Wittenberg AT, Wyman B, Zeng F, Zhang R (2006) GFDL's CM2 global coupled climate models. Part I: formulation and simulation characteristics. J Clim 19:643–674. doi: 10.1175/JCLI3629.1 CrossRefGoogle Scholar
- Hasumi H, K-1 model developers (2004) K-1 coupled model (MIROC) description, K-1 technical report, 1, Center for climate system research, University of Tokyo, 34 pp. Available at: http://www.ccsr.u-tokyo.ac.jp/kyosei/hasumi/MIROC/tech-repo.pdf
- Jones C, Gregory J, Thorpe R, Cox P, Murphy J, Sexton D, Valdes H (2004) Systematic optimization and climate simulation of FAMOUS, a fast version of HADCM3. Hadley Centre technical note 60, 33 pp. Available at http://www.metoffice.gov.uk/research/hadleycentre/pubs/HCTN/HCTN_60.pdf
- Nigam S, Chan S (2008) On the summertime strengthening of the Northern Hemisphere sea-level pressure anticyclone. J Climate (in press)Google Scholar
- Randall DA, Wood RA, Bony S, Colman R, Fichefet T, Fyfe J et al (2007) Climate Models and Their Evaluation. In: Solomon S, Qin D, Manning M, Chen Z, Marquis MC, Averyt KB, Tignor M, Miller HL (eds) Climate change 2007: the physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, p 996Google Scholar
- Roeckner E, Bäuml G, Bonaventura L, Brokopf R, Esch M, Giorgetta M, Hagemann S, Kirchner I, Kornblueh L, Manzini E, Rhodin A, Schlese U, Schulzweida U, Tompkins A (2003) The atmospheric general circulation model ECHAM5. Part I: Model description. Report No. 349. Max Planck Institute for Meteorology, Hamburg, Germany, 127 pp, ISSN 0937-1060Google Scholar
- Wu R, Kirtman BP, Pegion K (2007) Surface latent heat flux and its relationship with sea surface temperature in the National Centers for Environmental Prediction Climate Forecast System simulations and retrospective forecasts. Geophys Res Lett 34:L17712. doi: 10.1029/2007GL030751 CrossRefGoogle Scholar
- Yu L, Jin X, Weller RA (2008) Multidecade Global Flux Datasets from the Objectively Analyzed Air–sea Fluxes (OAFlux) Project: Latent and sensible heat fluxes, ocean evaporation, and related surface meteorological variables. Woods Hole Oceanographic Institution, OAFlux project technical report. OA-2008-01, Woods Hole, Massachusetts, 64 ppGoogle Scholar