Submitted to Journal of Climate

A mesoscale model in a doubly periodic domain with specified sea surface temperature (SST) is used to study tropical radiative-convective equilibrium states. It is shown that tropical mean relative humidity, cloud properties and implied climate sensitivity depend strongly on planetary rotation and the development of tropical cyclones in the model domain. Rotation leads to increased surface wind speeds, which speed up the hydrologic cycle and lead to an increase of atmospheric temperature. Tropical cyclones develop when uniform rotation is set to that of the Earth at 10˚N, if the model resolution is sufficient and the ambient vertical wind shear is not too great. The development of a tropical cyclone in the domain causes the precipitation and clouds to be organized by the synoptic and mesoscale flow. Precipitation intensity is increased, convective cloud area is decreased and average relative humidity in the free troposphere is decreased. Tropical cyclone development causes stronger sensitivity of the outgoing longwave radiation to surface temperature. The model results suggest that cloud and water vapor feedback processes in the tropics may be strongly sensitive to changes in the synoptic and mesoscale organization of the flow