An analysis of entrainment mixing processes in warm cumulus

We analyze the effect of aerosol, altitude, and horizontal location within cloud on mixing processes in warm cumulus clouds observed during the GoMACCS field campaign near Houston, TX in summer 2006. Cloud drop size distributions and cloud liquid water contents from the Artium flight phase-Doppler interferometer in conjunction with meteorological observations are used to investigate whether inhomogeneous versus homogeneous mixing is preferred for different aerosol regimes, height above cloud base or distance from cloud edge. Four complete days (two clean and two polluted) were studied. Satellite aerosol data from the TOMS and OMI instruments were analyzed for the selected flights to determine whether they were clean or polluted. We find evidence that cloud edges are primarily diluted by inhomogeneous mixing processes and that there is a tendency for mixing to be more homogeneous towards cloud top. Aerosol concentration appears to have little effect in determining mixing type, though this is most likely the result of the relatively small sample size collected using aircraft data.