Aerosol influences on decoupled Arctic mixed-phase stratocumulus

Mixed-phase stratus clouds are common during most of the year in the Arctic and exert a strong influence on Arctic climate through various feedback mechanisms. Due to their large horizontal extent and persistence as well as the presence of the radiatively-important liquid phase, mixed-phase low-level clouds have substantial impacts on the Arctic surface energy budget. Their persistence has been previously explained by a complex chain of interactions involving radiative, dynamical and microphysical processes. Of particular interests are the cases when the mixed-phase cloud layer is decoupled from the surface and is capable of maintaining itself without the supporting fluxes of energy and moisture from below. Here we investigate: (1) what factors are responsible for the decoupled cloud layer maintenance, and (2) how the aerosol-induced changes in cloud droplet and ice crystal size and number concentrations influence these factors. We will present results of large-eddy simulations with explicit aerosol treatment of one of the casedays observed during the recent Indirect and Semi-Direct Aerosol Campaign (ISDAC).