Lidar Monitoring at mid latitude of the stratospheric aerosol perturbation produced by the El Chichón eruption

Abstract

We report lidar measurements of the perturbation in the atmospheric dust load produced by the El Chichón volcanic eruption. The measurements extend for a 19 month period and are taken at a mid-latitude station. Analysis of the backscattering ratio and integrated backscattering as a function of altitude show that until the end of summer 1982, optical thickness was contributed mainly by high altitude (≥ 25 km) layers. Since the fall of 1982 the main cloud arrival at mid latitude formed a broad single !ayer extending from 15 to 30 km. Slow decay in the altitude of this layer, 7 - 8 km in 12 months, is attributed to a contribution of general circulation and settling velocity of the dust particles. It is shown that our optical thickness data are consistent with similar independent measurements.