Comparison of cloud properties between cloudsat retrievals and airplane measurements in mixed-phase cloud layers of weak convective and stratus clouds

Abstract

Cloud microphysical properties including liquid and ice particle number concentration (NC), liquid water content (LWC), ice water content (IWC) and effective radius (RE) were retrieved from CloudSat data for a weakly convective and a widespread stratus cloud. Within the mixed-phase cloud layers, liquid-phase fractions needed to be assumed in the data retrieval process, and one existing linear (p 1) and two exponential (p 2 and p 3) functions, which estimate the liquid-phase fraction as a function of subfreezing temperature (from −20°C to 0°C), were tested. The retrieved NC, LWC, IWC and RE using p 1 were on average larger than airplane measurements in the same cloud layer. Function p 2 performed better than p 1 or p 3 in retrieving the NCs of cloud droplets in the convective cloud, while function p 1 performed better in the stratus cloud. Function p 3 performed better in LWC estimation in both convective and stratus clouds. The REs of cloud droplets calculated using the retrieved cloud droplet NC and LWC were closer to the values of in situ observations than those retrieved directly using the p 1 function. The retrieved NCs of ice particles in both convective and stratus clouds, on the assumption of liquid-phase fraction during the retrieval of liquid droplet NCs, were closer to those of airplane observations than on the assumption of function p 1.