Convective‐scale responses of a large‐domain, modelled tropical environment to surface warming

Abstract

This article explores the response of convective‐scale atmospheric characteristics to surface temperature through the lens of large‐domain, cloud‐system‐resolving model experiments run at radiative convective equilibrium. We note several features reminiscent of the response to surface warming in atmospheric general circulation models. These include an increase in the rain rate that is smaller than the modelled increase in precipitable water, a systematic decrease in sensible heating and an increase in clear‐sky cooling. However, in contrast to climate models, we note that tropospheric relative humidity increases and column‐integrated water vapour increases at the rate anticipated from the Clausius–Clapeyron relationship, but only when compared with the troposphere mean temperature rather than surface temperature. Also shown are results elucidating the changes in the vertically integrated water budget and the distribution of high precipitation rates shifting toward higher rates. Moist static energy distributions are analyzed and, from these, clouds are implicated in effecting the final equilibrium state of the atmosphere. The results indicate that, while there are aspects of the tropical equilibrium that are represented realistically in current general circulation model climate‐change experiments, there are potentially influential local interactions that are sufficiently important as to alter the mean response of the tropical water and energy balance to changes in sea‐surface temperature. Convection is shown to dictate the equilibrium state across all scales, including those unresolved in climate models, rather than only responding to surface‐induced changes.