Atmospheric Ozone: Determination by Chappuis-Band Absorption

Abstract

Ozone content in the atmospheric column above Mauna Loa Observatory, Hawaii, was determined in experiments by measuring the attenuation of sunlight in the visible spectrum Chappuis bands (500 nm<?<700 nm wavelength). The dominant source of uncertainty in such determinations is the accuracy with which the magnitude of the published Chappuis-band absorption coefficients are known. Values of ozone (for 42 clear days) obtained by using Vigroux's absorption coefficients differed systematically, and were 17.6% smaller than those derived simultaneously in time and space with a Dobson spectrophotometer. The agreement with the Dobson values improves, but is not perfect, when Inn and Tanaka's absorption coefficients are used in the data analysis. Until more accurate information becomes available on ozone absorption coefficients, spectrophotometric-derived values of atmospheric ozone must be considered uncertain to 10?20%.