The influence of cloud-radiation interactions in the diurnal cycle of tropical oceanic deep convection in the East Pacific

While recent studies have underscored the importance of cloud-radiation interactions (CRIs) for the general behavior and evolution of tropical deep convection, their relative impact on the diurnal convective lifecycle and upscale growth remains unclear. In this study, clouds are made transparent to radiation in 10-day convection-permitting simulations of tropical convection in the east Pacific to test the importance of CRIs in diurnal convective evolution. We find that longwave CRIs enhance domain-mean precipitation at all times by supporting more widespread deep convective initiation and enhancing precipitation intensity within both isolated and organized convective types, yet with no discernible influence on upscale growth metrics (area and lifetime) in this experiment. In contrast, shortwave CRIs strongly suppress precipitation intensity from daytime organized deep convection, along with its upscale growth. The effect of CRIs on diurnal precipitation intensity and upscale growth metrics can be interpreted through their modifications of the atmospheric radiative heating profile.