Absolute Absorption Cross Section Measurements of Ozone and the Temperature Dependence at Four Reference Wavelengths Leading to Renormalization of the Cross Section between 240 and 350 nm

摘要

We have developed techniques for the preparation and preservation of pure ozone which have enabled its absolute cross section at important mercury-line reference wavelength 253.7 nm and at iron line wavelengths 283.3, 245.8 and 26.7 nm to be determined at the temperatures 293, 228 and 195 k. Specially constructed absorption cells are used together with existing spectrometers and associated equipment and light sources which have already been employed successfully to study the absolute cross section of ozone at longer wavelengths. This determination of the temperature dependence of the absolute cross section at 238.3, 245.8, 253.7 and 263.7 nm permit renormalization of the full relative cross sections for ozone between 240nm and 350nm. A tabular and computer accessible form of the ozone cross sections data has been made at 5/cm intervals. These absolute cross sections and their temperature dependence are needed for accurate calculations of the atmospheric transmission in the visible and near ultraviolet regions. Keywords: Ozone absorption cross sections; Hartley huggins bands; Ultraviolet; Temperature dependence; Optical depth. (mjm)