Optical, radiative, and source characteristics of aerosols at Minicoy, a remote island in the Southern Arabian Sea

Abstract

Extensive measurements of aerosol radiative and microphysical properties were made at an island location, Minicoy (8.3°N, 73.04°E) in the southern Arabian Sea. A large variability in aerosol characteristics associated with changes in air mass and precipitation characteristics was observed. Six distinct transport pathways were identified on the basis of cluster analysis. The Indo-Gangetic Plain, along with the northern Arabian Sea and west Asia (NWA), was identified to be the region having the highest potential for aerosol mass loading at the island. This estimate is based on the concentration weighted trajectory as well as cluster analysis. Dust transport from the NWA region was found to make a substantial contribution to the supermicron mass fraction. The black carbon mass mixing ratios observed were the lowest compared to previous measurements over this region. Consequently, the atmospheric radiative forcing efficiency was low and was in the range 10–28 W m⁻².