The El Chichon cloud over central Europe, observed by lidar at Garmisch-Partenkirchen during 1982

The transport to northern midlatitudes of stratospheric aerosol layers originating from the 4 April 1982 explosive eruption of the Mexican volcano El Chichon took place in three phases: Appearance of a stable low altitude aerosol layer (tropopause to 20 km) in May, observable until October; appearance of a second, rather variable, high altitude layer (above 20 km) in June, observable until October; formation of a broad layer in October, extending from the tropopause to 30 km, and a subsequent steady increase of the aerosol loading until the end of 1982. Observed lidar backscattering profiles have been converted to optical depth and column mass values. Respective December 1982 averages of 0.13 at 550 nm and 0,04 g m E-2 have been derived. (IFU)