Airborne and Ground-Based lidar measurements of the El Chichón stratospheric aerosol from 90°N to 56°S

Abstract

This paper presents the results of a number of airborne lidar campaigns, covering latitudes from 90°N to 56°S over the period July 1982 to January 19.84 . These flights were designed to determine key characteristics of the stratospheric aerosol produced from March-April 1982 eruptions of El Chichón. Also discussed is the 10-year ground based lidar data set at NASA Langley (37°). Backscatter ratios, integrated aerosol backscatter functions, column mass densities, and mass of the stratospheric aerosol versus latitude and, where appropriate, altitude are described.Two general stratospheric-layer regions are shown to exist initially after the eruption, one above 20 km and one below 20 km. Toe material below about 20 km moved to higher latitudes, followed by the material above 20 km which for the most part, was constrained to an equatorial belt between about 10°S and 30°N for approximately 6 months. In the early fall of 1982, the total global stratospheric increase due to El Chichón was estimated to be 12 megatonnes. Toe maximum global impact is thought to have occurred between the July and October 1982 missions. Maximum stratospheric effects at 37ºN were experienced in January 1983. Toe maximuni column density was seen to move north in time. Toe altitude of the peak of stratospheric material moved downward and the layer broadened in width as the material aged.