Boundary layer aerosols at Trivandrum tropical coast

Characteristics of aerosols in the atmospheric boundary layer (ABL) has been studied using the data obtained from particle samplers and altitude profiles of aerosol number density obtained using a continuous wave lidar. The aerosol concentration near the surface is strongly influenced by mesoscale features of sea breeze and also strongly influenced by synoptic ABL meteorology. Relative concentration of submicron particles is high in winter and summer and low during the monsoon period. Submicron particles generated over the continent are significant in summer and winter. Sea-spray is the important source mechanism during the monsoon period. Strong convective activity prevailing in summer is very effective in the vertical transport of aerosols, while the sea-spray aerosols predominantly produced in the southwest monsoon period remains more or less confined to lower altitudes in ABL. A long-term increasing trend in aerosol optical depth is observed at this experimental site, which appears to be significantly governed, by regional transport rather than local production.