Impact of aerosols on deep convective clouds using integrated remote sensing techniques

Abstract

Remote sensing techniques were used to study the impact of aerosols on deep convective clouds and their abilities to act as cloud condensation nuclei (CCN) that formed on 21 May 2011 over Gandhi college region, India. Analysis using MODIS images and AERONET data indicated that dust particles were advected into the atmosphere during the dust storm. Angstrom values of 0.7 to 0.8 and refractive index values of 1.43 to 1.47 obtained from AERONET indicate the presence of dust particles that got coated with sulfate. These sulfate-coated dust particles enhanced its ability to act as CCN by permitting the hygroscopic growth in subsaturated condition. The hygroscopic growth of dust particles was seen from an increase in fine particles in aerosol optical depth (AOD). Under the subsaturated condition, the water vapor froze and initiated ice formation. Thus, the aerosol-induced convection enhancement was a combination of delayed warm rain and enhanced mixed-phase processes within the clouds. The present study indicates that the impact of aerosols on clouds is location specific and satellite data along with ground-based measurements could be used to determine factors influencing the formation of deep convective clouds leading to heavy rainfall.