Aerosol characteristics over coastal regions of the Arabian sea

From aerosol spectral optical depths (tau(p lambda)) at 10 wavelengths in the range 380 to 1025 nm estimated at different locations in the near and far coastal regions of the Arabian sea adjoining the western coast of central India, the spatial and spectral characteristics of coastal aerosols and the effect of the proximity to the (urban) continent are investigated. The Angstrom parameters are deduced from tau(p lambda) values. A significant increase, both in aerosol optical depths at shorter (visible) wavelengths (lambda less than or equal to 600 nm) and the Angstrom wavelength exponent are observed in the near coastal regions, suggesting an increase in the (relative) concentration of sub micron particles, apparently of anthropogenic origin. The Angstrom turbidity coefficient remains nearly steady spatially, indicating a (spatially) uniform loading of large particles.