1. Spatial and temporal evolution of the optical thickness of the Pinatubo aerosol cloud in the northern hemisphere from a network of ship-borne and stationary lidars



The vertical profiles of the extinction coefficient and the total optical thickness of the Pinatubo aerosol layer obtained from a network of 5 Rayleigh-Mie lidars are presented here. Three ship-borne lidars (PROFESSOR ZUBOV†, PROFESSOR VIZE†, HENRI POINCARE*) and two fixed lidar stations (OHP* and CEL*) are operated respectively by the Roscomhydromet†, of Russia and of the Service d'Aeronomie du CNRS* of France. The measurements presented are in the altitude range 15–35 km. They were obtained between July 1991 - April 1992 and cover 8°S–60°N latitude and 80°W–6°E longitude. This represents extensive coverage of the western sector of the northern hemisphere, which is partly coincident with UARS satellite coverage. Optical depths of up to 0.2 were observed and maximum extinction coefficient values of 0.08 km−1 were obtained at 24 km and 18°N latitude.