Mid‐latitude stratospheric aerosol layer enhancement by El Chichon: The first year

Abstract

Measurements are reported in this paper which indicate the nature of the enhancement of the stratospheric aerosol layer by month for the first full year following the Spring 1982 eruptions of El Chichon. The aerosol optical depths as a function of wavelength are obtained by differencing mean monthly values obtained before and after the eruptions. The first enhancement above background was detected in September 1982. The inverted size distributions indicate a steady increase to larger mean size particles each month with a radius near 0.6 micrometers during the last reported month of March 1983. This size is considerably larger than that which is generally assumed for the sulfuric acid aerosols which form following an eruption.