Testing the FAT hypothesis in a cloud-resolving model

Zhiming Kuang and Dennis L. Hartmann

Journal of Climate, 2007, 20, 2051-2057,


Using cloud-resolving simulations of tropical radiative-convective equilibrium, we show that the anvil temperature changes by less than 0.5K with a 2K change in SST, lending support to the Fixed Anvil Temperature (FAT) hypothesis (Hartmann and Larson, 2002). Our results suggests that, for plausible ozone profiles, decrease in the airs emission capability, instead of ozone heating, shall remain as the control on the detrainment level, and the FAT hypothesis should hold. The anvil temperature also remains unchanged with other changes in the system such as doubled CO2 mixing ratio, doubled stratospheric water vapor concentration, and dynamical cooling due to the Brewer-Dobson circulations. The results are robust when a different microphysics scheme is used. These results indicate that we should expect anvil temperatures to remain constant as the surface warms in a warmer climate.
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Zhiming Kuang <kuang@fas.harvard.edu>