This research was supported partially by NOAA’s Office of Global Programs (the Climate Dynamics Program and Experimental Prediction Program, and the CLIVAR Pacific Program), and partially by the NSF Climate Dynamics Program (ATM-9912434 and ATM-0331760). Using data from the Atmospheric Model Intercomparison Project (AMIP), this work was also partially supported under the auspices of the U.S. Department of Energy, Office of Science, at the University of California’s Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. Hack and Kiehl acknowledge support from the Department of Energy Office of Science Climate Change Prediction Program. The National Center for Atmospheric Research (NCAR) is sponsored by the National Science Foundation. The lead author (D.-Z. Sun) would like to thank Dr. Robert Dickinson for his encouraging comments. D.-Z. Sun would also like to thank Dr. Ping Chang and Dr. R. Saravanan for the conversations on the causes of the double ITCZ in coupled models. The helpful suggestions from the two anonymous reviewers and the editor, Dr. Anthony Del Genio, are also gratefully acknowledged.
Allan, R. P., M. A. Ringer, and A. Slingo, 2003: Evaluation of moisture in the Hadley Centre climate model using simulations of HIRS water-vapor channel radiances. Quart. J. Roy. Meteor. Soc., 129:3371–3389.
Barkstrom, B. R., E. F. Harrison, G. L. Smith, R. Green, J. Kibler, and R. D. Cess, the ERBE Science Team 1989: Earth Radiation Budget Experiment (ERBE) archive and April 1985 results. Bull. Amer. Meteor. Soc., 70:1254–1262.
Bauer, M., A. D. Del Gienio, and J. R. Lanzante, 2002: Observed and simulated temperature–humidity relationships: Sensitivity to sampling and analysis. J. Climate, 15:203–215.
Boer, G. J., B. Yu, S-J. Kim, and G. M. Flato, 2004: Is there observational support for an El Niño-like pattern of future global warming? Geophys. Res. Lett., 31.L06201, doi:10.1029/2003GL018722.
Cai, W. and P. H. Whetton, 2000: Evidence for a time-varying pattern of greenhouse warming in the Pacific Ocean. Geophys. Res. Lett., 27:2577–2580.
Cess, R. D. and G. L. Potter, 1988: A methodology for understanding and intercomparing atmospheric climate feedback processes in general circulation models. J. Geophys. Res., 93:8305–8314.
Chou, M-D. and M. J. Suarez, 1996: A solar radiation parameterization (CLIRAD-SW). NASA Tech. Memo. 104606, Vol. 15, 48 pp.
Collins, M., S. F. B. Tett, and C. Cooper, 2001: The internal climate variability of a HadCM3, a version of the Hadley Centre coupled model without flux adjustments. Climate Dyn., 17:61–81.
Collins, W. D., Coauthors 2003: Description of the NCAR Community Atmosphere Model (CAM2). 189 pp. [Available online at http://www.ccsm.ucar.edu/models/atm-cam/docs/cam2.0/description.pdf.].
Collins, W. D., Coauthors 2004: Description of the NCAR Community Atmosphere Model (CAM 3.0). NCAR Tech. Rep. NCAR/TN-464+STR, Boulder, CO, 210 pp.
Delworth, T. L., Coauthors 2006: GFDL’s CM2 global coupled climate models. Part I: Formulation and simulation characteristics. J. Climate, 19:643–674.
Fu, R., A. D. DelGenio, W. B. Rossow, and W. T. Liu, 1990: Cirrus cloud thermostat for tropical sea surface temperature tested using satellite data. Nature, 358:394–397.
GFDL Global Atmospheric Model Development Team 2004: The new GFDL global atmosphere and land model AM2/LM2: Evaluation with prescribed SST simulations. J. Climate, 17:4641–4673.
Grandpeix, J-Y., V. Phillips, and R. Tailleux, 2004: Improved mixing representation in Emanuel’s convection scheme. Quart. J. Roy. Meteor. Soc., 130:3207–3222.
Gregory, D. and P. R. Rowntree, 1990: A mass flux convection scheme with representation of cloud ensemble characteristics and stability-dependent closure. Mon. Wea. Rev., 118:1483–1506.
Hack, J. J., 1994: Parameterization of moist convection in the National Center for Atmospheric Research Community Climate Model (CCM2). J. Geophys. Res., 99:5551–5568.
Kiehl, J. T., J. J. Hack, G. Bonan, B. A. Boville, D. Williamson, and P. J. Rasch, 1998: The National Center for Atmospheric Research Community Climate Model: CCM3. J. Climate, 11:1131–1149.
Lock, A. P., A. R. Brown, M. R. Bush, G. M. Martin, and R. N. B. Smith, 2000: A new boundary layer mixing scheme. Part I: Scheme description and single-column model tests. Mon. Wea. Rev., 128:3187–3199.
Marti, O., Coauthors cited. 2005: The new IPSL climate system model: IPSL CM4. [Available online at http://dods.ipsl.jussieu.fr/omamce/IPSLCM4/DocIPSLCM4/FILES/DocIPSLCM4.pdf.].
Meehl, G. A. and W. M. Washington, 1996: El Niño-like climate change in a model with increased atmospheric CO2 concentrations. Nature, 382:56–60.
Mellor, G. L. and T. Yamada, 1974: A hierarchy of turbulence closure models for planetary boundary layers. J. Atmos. Sci., 31:1791–1806.
Moorthi, S. and M. Suarez, 1992: Relaxed Arakawa–Schubert: A parameterization of moist convection for general circulation models. Mon. Wea. Rev., 120:978–1002.
Murtugudde, R., J. Beauchamp, C. R. McClain, and A. J. Busalacchi, 2002: Effects of penetrative radiation on the upper tropical ocean circulation. J. Climate, 15:470–496.
Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, 1992: Numerical Recipes. Cambridge University Press, 963 pp.
Ramanathan, V. and W. Collins, 1991: Thermodynamic regulation of ocean warming by cirrus clouds deduced from observations of the 1987 El Niño. Nature, 351:27–32.
Rayner, N. A., E. B. Horton, D. E. Parker, C. K. Folland, and R. B. Hackett, 1996: Version 2.2 of the Global Sea-Ice and Sea Surface Temperature Data Set, 1903–1994. Climate Research Tech. Note 74 (CRTN74), Hadley Centre for Climate Prediction and Research, Met Office, Exeter, Devon, United Kingdom, 35 pp.
Soden, B. J., R. T. Wetherald, G. L. Stenchikov, and A. Robock, 2002: Global cooling after the eruption of Mount Pinatubo: A test of climate feedback by water vapor. Science, 296:727–730.
Soden, B. J., A. J. Broccoli, and R. S. Hemler, 2004: On the use of cloud forcing to estimate cloud feedbacks. J. Climate, 17:3661–3665.
Stockdale, T. N., A. J. Busalacchi, D. E. Harrison, and R. Seager, 1998: Ocean modeling for ENSO. J. Geophys. Res., 103:14325–14355.
Suarez, M. J., 1995: Documentation of the ARIES/GEOS Dynamical Core, version 2. NASA Tech. Memo. 104606, Vol. 5, 53 pp.
Sun, D-Z. and I. Held, 1996: A comparison of modeled and observed relationships between interannual variations of water vapor and temperature. J. Climate, 9:665–675.
Sun, D-Z. and K. E. Trenberth, 1998: Coordinated heat removal from the tropical Pacific region during the 1986–87 El Niño. Geophys. Res. Lett., 25:2659–2662.
Sun, D-Z., J. Fasullo, T. Zhang, and A. Roubicek, 2003: On the radiative and dynamical feedbacks over the equatorial Pacific cold tongue. J. Climate, 16:2425–2432.
Timmerman, A. J., J. Oberhuber, A. Bacher, M. Esch, M. Latif, and E. Roeckner, 1999: Increased El Niño frequency in a climate model forced by future global warming. Nature, 398:694–696.
Trenberth, K. E. and C. J. Guillemot, 1998: Evaluation of the atmospheric moisture and hydrological cycle in the NCEP reanalyses. Climate Dyn., 14:213–231.
Trenberth, K. E., J. M. Caron, and D. P. Stepaniak, 2001: The atmospheric energy budget and implications for surface fluxes and ocean heat transport. Climate Dyn., 17:259–296.
Uppala, S., Coauthors 2004: ERA-40: ECMWF 45 year reanalysis of the global atmosphere and surface conditions 1957–2002. ECMWF Newsletter, No. 101, ECMWF, Reading, United Kingdom, 2–21.
Wittenberg, A. T., A. Rosati, N-C. Lau, and J. J. Ploshay, 2004: GFDL’s CM2 global coupled models. Part III: Tropical Pacific climate and ENSO. J. Climate, 19:698–722.
Xie, P. and P. A. Arkin, 1996: Analyses of global monthly precipitation using gauge observations, satellite estimates, and numerical model predictions. J. Climate, 9:840–858.
Yanai, M., S. Esbensen, and J-H. Chu, 1973: Determination of bulk properties of tropical cloud clusters from large-scale heat and moisture budgets. J. Atmos. Sci., 30:611–627.
Zhang, G. J. and N. A. McFarlane, 1995: Sensitivity of climate simulations to the parameterization of cumulus convection in the Canadian Climate Centre general circulation model. Atmos.–Ocean, 33:407–446.
Zhang, M. H., R. D. Cess, T. Y. Kwon, and M. H. Chen, 1994: Approaches of comparison for clear-sky radiative fluxes from general circulation models with Earth Radiation Budget Experiment data. J. Geophys. Res., 99:5515–5523.