O₃ profiles retrieved from limb scatter measurements: Theory

Abstract

An algorithm is presented for retrieving vertical profiles of O 3 concentration using measurements of UV and visible light scattered from the limb of the atmosphere. The UV measurements provide information about the O 3 profile in the upper and middle stratosphere, while only visible wavelengths are capable of probing the lower stratospheric O 3 profile. Sensitivity to the underlying scene reflectance is greatly reduced by normalizing measurements at a tangent height high in the atmosphere (∼55 km), and relating measurements taken at lower altitudes to this normalization point. To decrease the effect of scattering by optically thin aerosols/clouds that may be present in the field of view, these normalized measurements are then combined by pairing wavelengths with strong and weak O 3 absorption. Excluding pointing errors, we conclude that limb scatter can be used to measure O 3 between 15 km and 50 km with 2–3 km vertical resolution and better than 10% accuracy.