Turbulence structure in shallow precipitating cumulus convection*

Low clouds are one of the largest sources of uncertainty in climate projections. The development of precipitation in shallow cumulus clouds (cloud tops less than 4 km high) add additional complexity to the atmospheric boundary layer dynamics. Precipitation affects the atmospheric boundary layer energy balance and modulates the large-scale horizontal organization of convection. The turbulence structure of the boundary layer is studied using large-eddy simulation (LES). We present results from an unprecedented size LES, with a domain of 330 km and 40 m grid resolution. The LES captures both cloud-scale and mesoscale flow organization. The horizontal flow organization is quantified using the premultiplied spectra and the scaling of the temperature and humidity fluxes is discussed.