Turbulent activation of cloud condensation nuclei

This dataset contains selected codes and data from simulations investigating the impact of cloud-base turbulence on activation of cloud condensation nuclei (CCN). Activation of two monodisperse CCN are studied within an adiabatic parcel rising through the cloud base and filled with homogeneous isotropic turbulence. We apply a forced implicit large eddy simulation methodology (Grabowski and Thomas Atmospheric Chemistry and Physics, 2021) within a triply periodic computational domain of (64m)^3. Small CCN are assumed to have a dry radius of 0.01 micron and a corresponding activation (critical) radius and activation supersaturation of 0.6 micron and 1.3%, respectively. Large CCN have a dry radius of 0.2 micron and feature activation radius of 5.4 micron and activation supersaturation 0.15 %. CCN are assumed in 200 cm^-3 concentration in all cases. Mean cloud base updraft velocities of 0.33, 1, and 3 m/s are considered. Turbulence can lead to activation of only a fraction of all CCN and lead to a non-zero droplet spectral width just above the cloud base, of the order of 1 micron, especially in the case of small CCN and weak mean cloud base ascent. The simulations document an important role of cloud base turbulence on cloud base CCN activation.