Chemical composition of atmospheric aerosols over the Indian Ocean: impact of continental advection

The advection of continental aerosols over to the marine environments of Indian Ocean and Arabian Sea during northern hemispheric winter have been studied based on the chemical composition of aerosols collected from these regions. The aerosol samples collected on INDOEX cruise were analysed for anions like SO4, NO3 and Cl and cations of Na, K, Mg, Mn, Zn, Fe, Cu, Ca and Pb. North of the Inter Tropical convergence Zone (ITCZ) the mass concentrations of ions like SO4, NO3, Cu, Fe, etc. which are mostly of continental/anthropogenic origin were significantly higher than the oceanic background values. South of ITCZ and in the remote oceanic regions ions like Na, Cl, Mg, etc. which are mostly of oceanic origin, were more prominent. The sea-salt (SS) and non-sea-salt (NSS) components of aerosols exhibit distinctly different spatial pattern and wind-dependence.