Determination of vertical ozone distributions by spacecraft measurements using a limb-scan technique

Abstract

A method for inference of vertical ozone profiles from measurements of the limb radiance resulting from scattered solar ultraviolet radiation is described in terms of a new inversion technique using multiple wavelengths. The inversion equation for this method is based on weighting functions which correspond to the sensitivity of the limb radiance to the relative increment of ozone density at each altitude, and the equation is solved by an iteration technique. In principle, the ozone vertical profile can be recovered from the inversion of a limb scan at a single wavelength. In practice, however, much more information of a higher accuracy over a wider height range can be obtained if one uses multiple wavelengths. Computer simulations were done for 280, 300, 320, and 340 nm. These results indicate the feasibility of determining ozone profiles on a global basis from satellite platforms over the altitude range of ~20-70 km with a vertical resolution of 1-2 km. The inferred profile error is about three to four times larger than measurement error in the 20-70-km altitude region. If one uses the wavelengths down to 260 nm, the accuracy of ozone profile of the highest altitude region may be improved. Ozone densities can be inferred above 70 km from the observations, although the errors are significantly larger.