Validation of the ORA spatial inversion algorithm with respect to the Stratospheric Aerosol and Gas Experiment II data

Optical and physical properties of stratospheric aerosols from balloon measurements in the visible and near-infrared domains. 1. Analysis of aerosol extinction spectra from the AMON and SALOMON balloonborne spectrometers

Aerosol extinction coefficients have been derived in the 375-700-nm spectral domain from measurement in the stratosphere since 1992, at night, at mid- and high latitudes from 15 to 40 km, by two balloonborne spectrometers, Absorption par les Minoritaires Ozone et NO(chi) (AMON) and Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NO(chi) (SALOMON). Log-normal size distributions associated with the Mie-computed extinction spectra that best fit the measurements permit calculation of integrated properties of the distributions. Although measured extinction spectra that correspond to background aerosols can be reproduced by the Mie scattering model by use of monomodal log-normal size distributions, each flight reveals some large discrepancies between measurement and theory at several altitudes. The agreement between measured and Mie-calculated extinction spectra is significantly improved by use of bimodal log-normal distributions. Nevertheless, neither monomodal nor bimodal distributions permit correct reproduction of some of the measured extinction shapes, especially for the 26 February 1997 AMON flight, which exhibited spectral behavior attributed to particles from a polar stratospheric cloud event.

Remote Sensing of the Earth 's Atmosphere by the Spaceborne Occultation Radiometer, ORA: Final Inversion Algorithm

We describe the final inversion algorithm developed to process solar occultation data measured in 1992-1993 by the Occultation Radiometer (ORA) spaceborne experiment. First we develop a new method to improve the ORA total extinction altitude profiles retrieved with the previously described Natural Orthogonal Polynomial Expansion (NOPE) method. Using these improved profiles, we perform spectral inversion and obtain altitude density profiles for O(3) and NO(2) and extinction profiles for the aerosols. Validation of number density profiles between the Stratospheric Aerosol and Gas Experiment II (SAGE II) and the ORA shows satisfactory agreement.