DISCRIMINATION OF CLOUD AND AEROSOL IN THE STRATOSPHERIC-AEROSOL-AND-GAS-EXPERIMENT-III OCCULTATION DATA

The Stratospheric Aerosol and Gas Experiment (SAGE) III, scheduled for a first launch in mid-1998, will be making measurements of the extinc tion that is due to aerosols and gases at many wavelengths between 385 and 1550 nm. In the troposphere and wintertime polar stratosphere, ex tinction will also occur because of the presence of cloud along the op tical path from the Sun to the satellite instrument. We describe a met hod for separating the effects of aerosol and cloud using the extincti on at 525, 1020, and 1550 nm and present the results of simulation stu dies. These studies show that the new method will work well under back ground nonvolcanic aerosol conditions in the upper troposphere and low er stratosphere. Under conditions of severe volcanic contamination, th e error rate for the separation of aerosol and cloud may rise as high as 30%. (C) 1997 Optical Society of America.