DISSIPATION OF MARINE STRATIFORM CLOUDS AND COLLAPSE OF THE MARINE BOUNDARY-LAYER DUE TO THE DEPLETION OF CLOUD CONDENSATION NUCLEI BY CLOUDS

When the production of cloud condensation nuclei in the stratocumulus-topped marine boundary layer is low enough, droplet collisions can reduce concentrations of cloud droplet numbers to extremely low values. At low droplet concentrations a cloud layer can become so optically thin that cloud-top radiative cooling cannot drive vertical mixing. Under these conditions, model simulations indicate that the stratocumulus-topped marine boundary layer collapses to a shallow fog layer. Through this mechanism, marine stratiform clouds may limit their own lifetimes.