First observations of aerosol black carbon over coastal Arabian Sea during ARMEX

Abstract

Extensive measurements of the mass concentrations of BC and composite aerosols were made for the first time during the inter-monsoon and summer monsoon seasons (March to June, 2003) over coastal Arabian Sea region under the Arabian Sea Monsoon Experiment (ARMEX). Results showed a gradual and continuous decrease (by a factor of 7) in the mean concentration of BC from ~700 ng m-3 in March to reach as low as ~ 104 ng m-3 in June. The diurnal variations were very weak during March, weakened progressively and almost vanished by May and June. Consistent with this, there is a rapid decrease in the share of BC to the composite aerosol system.