Abstract

Ground and aircraft based measurements in the ultraviolet and visible spectral regions have provided critical information about the composition and time evolution of stratospheric trace gases. The technique has been especially useful in detecting nitrogen and chlorine species important to the interpretation of the Antarctic ozone hole and is now being used to measure changes in trace gas composition of the stratosphere that affect ozone depletion. Many molecular species possess highly structured absorption spectra, and measurement of their stratospheric abundance can be accomplished by observation of the scattered sunlight in the zenith sky during the day or the Moon at night; diurnal changes can be measured over a 24 h period. The technique was first developed in the 1970's and has now reached a level of sophistication such that absorptions as low as 0.02% absorption can be measured in less than 5 min integration time. New instrumentation under development to make these measurements will be discussed, as will the advantages and disadvantages of this method.

© 1992 Optical Society of America