Sensitivity of precipitating cloud radiative efficiencies to the environment using A-Train and reanalysis data

Cloud feedbacks remain one of the largest sources of uncertainty in model climate sensitivity estimates, partly because of the complicated interactions between convective processes, radiative effects, and the large-scale circulation. Cloud radiative effects and precipitation processes have been linked in both deep convective and low cloud regimes, which points to the importance of understanding the connections between the latent heating from precipitation and surface and atmospheric cloud radiative effects. Here we use a set of cloud impact parameters that characterize how efficiently a precipitating cloud heats the atmosphere or cools the surface. The surface radiative cooling efficiency, rc, represents the ratio of the shortwave cloud radiative effect at the surface to latent heat release from precipitation. The atmospheric heating efficiency, rh, describes a cloud's ability to heat the atmosphere per unit latent heat release from precipitation. In this study, CloudSat-CALIPSO products are combined with reanalysis data to study the thermodynamic and dynamic regime dependence, including the sensitivity to sea surface temperature (SST), column water vapor (CWV), vertical velocity, convective available potential energy (CAPE), lower tropospheric stability (LTS), moist static energy (MSE), of precipitating cloud radiative impact parameters. Preliminary results show that there is a clear link between dynamical regime and both cooling and heating efficiencies. With increasing surface wind speeds appear to modulate the strength of the heating and cooling efficiencies in different regimes. The thermodynamic variables are most important near the tails of the thermodynamic variable distributions, with CWV more important than SST for rh and SST more important for rc. The sensitivities of the cloud radiative efficiencies to environmental variables are also highly scale-dependent, so the scale dependence of precipitating cloud radiative impact parameters will also be examined.