Are Aerosols Inducing Heterogeneity in Cloud and Ice Droplet Radius Over India?

Abstract:

The most important cloud property is cloud droplet effective radius (CDR), which is modulated by aerosols and atmospheric water vapor. The aerosol effect on cloud properties can be region specific and warrants consideration of regional variability for understanding aerosol-cloud interactions. Here, using 16 years of observational data of monsoon season I found that the liquid- and ice-CDR are decreasing over the south-central (SC), south-western (SW) and eastern coastal (EC) India at a rate of ~ -0.10 to -0.20 μm/yr whereas, over the north-western India only liquid-CDR is increasing at a rate of ~0.15 μm/yr with presence of a casual effect of aerosol on CDR. Moreover, the aerosol induced modulation of CDR is asymmetric, i.e. presence of both anti-Twomey (over Indo-Gangetic plain) and Twomey (over SC, SW and EC India) effects causing a local differential cooling of the surface which can affect the local dynamical circulation, and consequently monsoon pattern.