GROUND-BASED REMOTE SENSING OF THE SIZE DISTRIBUTION OF PINATOBU’S VOLCANIC CLOUD^*

In this paper,data of solar direct spectral radiance observation in summer and autumn of 1990 and 1991 were used to derive the average atmospheric extinction spectra for very clear days each year.The difference of these two extinction spectra is obvious and considered as the contribution of volcanic cloud resulting from Pinatobu's volcanic eruption in middle June of 1991.This average size distribution of volcanic cloud was retrieved from the difference spectra and given in this paper which will be useful for estimation and modeling of the effects of volcanic eruption.