Correlative measurements of aerosol optical depth and size distribution around INDOEX–FFP 98 from multi-spectral solar radiometry

Spectral aerosol optical depth measurements by means of ground-based solar radiometry have been made at the Indian Institute of Tropical Meteorology, Pune, a continental urban station in India, as part of the INDOEX–FFP during 17 February through 31 March, 1998. The aerosol optical depths and corresponding size distributions observed with both a multichannel radiometer (sun-photometer) and a spectro-radiometer agree well and show marked variations during the experimental period. The day-to-day variation in the aerosol optical depth at 0.50 μm indicates an increasing trend. The results of a comparative study made between the continental urban and coastal aerosol characteristics using the sun-photometric observations carried out around the INDOEX–FFP 98 are also presented.