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GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L12707, doi:10.1029/2008GL033872, 2008

Effects of doubled CO2 on tropical sea surface temperatures (SSTs) for onset of deep convection and maximum SST: Simulations based inferences

Y. C. Sud

Laboratory for Atmospheres, NASA GSFC, Greenbelt, Maryland, USA


G. K. Walker

Science Applications International Corp., Beltsville, Maryland, USA


Y. P. Zhou

Goddard Earth Science and Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA


Gavin A. Schmidt

Goddard Institute of Space Studies, New York, New York, USA


K.-M. Lau

Laboratory for Atmospheres, NASA GSFC, Greenbelt, Maryland, USA


Robert F. Cahalan

Laboratory for Atmospheres, NASA GSFC, Greenbelt, Maryland, USA


Abstract

A primary concern of CO2-induced warming is the associated rise of tropical (10S-10N) sea-surface temperatures (SSTs). GISS Model-E was used to produce two sets of simulations-one with the present-day and one with doubled CO2 in the atmosphere. The intrinsic usefulness of model guidance in the tropics was confirmed when the model simulated realistic convective coupling between SSTs and atmospheric soundings and that the simulated-data correlations between SSTs and 300 hPa moist-static energies were similar to the observed. Model predicted SST limits for (i) the onset of deep convection and (ii) maximum SST, increased in the doubled CO2 environment. Changes in cloud heights, cloud frequencies, and cloud mass-fractions showed that convective-cloud changes increased the SSTs, while warmer mixed-layer of the doubled CO2 contained ∼10% more water vapor; clearly that would be conducive to more intense storms and hurricanes.

Received 5 March 2008; accepted 1 May 2008; published 24 June 2008.

Keywords: tropical warming; highest SST; moist convection.

Index Terms: 1630 Global Change: Impacts of global change (1225); 1635 Global Change: Oceans (1616, 3305, 4215, 4513); 1655 Global Change: Water cycles (1836); 1616 Global Change: Climate variability (1635, 3305, 3309, 4215, 4513); 1626 Global Change: Global climate models (3337, 4928).

Read Full Article (file size: 325503 bytes)    Cited by

Citation: Sud, Y. C., G. K. Walker, Y. P. Zhou, G. A. Schmidt, K.-M. Lau, and R. F. Cahalan (2008), Effects of doubled CO2 on tropical sea surface temperatures (SSTs) for onset of deep convection and maximum SST: Simulations based inferences, Geophys. Res. Lett., 35, L12707, doi:10.1029/2008GL033872.