Mode radius and asymmetry factor of Mt. Pinatubo volcanic aerosols from balloon‐borne optical measurements over Hyderabad during October 1991

Using Sun‐tracking photometers onboard balloon, the Pinatubo volcanic aerosol layer has been studied over Hyderabad (17.5°N) in October 1991, about 4 months after the eruption. From the aerosol extinction coefficients the mode radius and from the angular distribution of the scattered radiation intensity measurements the asymmetry factor g are determined. Mode radii are found to be in the range of 0.22±0.05 µm within the aerosol layer while g values are found to be 0.83±0.04, indicating the presence of larger particles. The mass determination reveals that the mass of the Pinatubo layer is about 0.053 gm −2 which is 3.75 times higher than the earlier reported value for El Chichon layer, about 4 months after the eruptions.