Aircraft measurements of cloud–aerosol interaction over East Inner Mongolia

Abstract

To investigate the potential effects of aerosols on the microphysical properties of warm clouds, airborne observational data collected from 2009 to 2011 in Tongliao, Inner Mongolia, China, were statistically analyzed in this study. The results demonstrated that the vertical distribution of the aerosol number concentration (N a) was similar to that of the clean rural continent. The average aerosol effective diameter (D e) was maintained at approximately 0.4 μm at all levels. The data obtained during cloud penetrations showed that there was a progressive increase in the cloud droplet concentration (N c) and liquid water content (LWC) from outside to inside the clouds, while the N a was negatively related to the N c and LWC at the same height. The fluctuation of the N a, N c and LWC during cloud penetration was more obvious under polluted conditions (Type 1) than under clean conditions (Type 2). Moreover, the wet scavenging of cloud droplets had a significant impact on the accumulation mode of aerosols, especially on particles with diameters less than 0.4 μm. The minimum wet scavenging coefficient within the cloud was close to 0.02 under Type 1 conditions, while it increased to 0.1 under Type 2 conditions, which proved that the cloud wet scavenging effect under Type 1 conditions was stronger than that under Type 2 conditions. Additionally, cloud droplet spectra under Type 1 conditions were narrower, and their horizontal distributions were more homogeneous than those under Type 2 conditions.