Spatial distribution of aerosol concentrations over the Arabian Sea and the Indian Ocean during IFP of INDOEX

During the intense field phase of the INDOEX, a high volume sampler was sai led on cruise to collect aerosol samples from different oceanic environment s. The variation of aerosol mass concentration (m) with latitude and longit ude was studied, The aerosol concentration near the West Coast is similar t o 40 mug/m(3), which is almost twice the amount that was observed in this r egion during FFP-98, This is in agreement with the data obtained from surfa ce measurement at Trivandrum, An enhancement in m was observed similar to 5 degreesN associated with the convergence of air stream coming over Arabian Sea, Bay of Bengal and the eastern parts, During the cruise period, the IT CZ located around 4 degreesS is rather broad and less dynamic, A, significa nt decrease in m was observed in this region. A significant enhancement in m was observed around 20 degreesS during the up leg along the longitudinal sector 70-75 degreesE. During the return leg an enhancement in m is observe d in the northern hemisphere, with increasing latitude (in the Arabian Sea sector), The aerosol loading increases further north of Goa towards the Bom bay coast. The overall spatial pattern of m during IFP-99 compares favourab ly with that observed during FFP-98.