Spectrally resolved measurements of the El Chichon cloud, may 1982 - august 1983

Abstract

Measurements ofthe atmospheric extinction from 330 to 840 nm were made daily in May 1982 and monthly thereafter, revealing the arrival and evolution of the cloud ofvolcanic debris and condensates over Flagstaff, Arizona. The optical depth of the cloud peaked at  ͌0.3 on 15 May and remained at levels of about 0.1 throughout the remainder of 1982. By the fall of 1983; it had dropped to  ͌0.5.  The wavelength dependence of extinction is consistent with the global transport of the cloud and with the changes in its particle size distribution reported in other papers in this volume.