Variability in the determination of total atmospheric ozone using remote sensing spectroscopic techniques

A spectroscopic method for optical remote sensing of total ozone (O₃) is described. It involves detailed spectral matching of near ultraviolet solar observations with synthetic profiles containing various amounts of ozone absorption. Application of this technique is made to airborne solar measurements in the 3100 to 3600 Å wavelength region. In the 3100 to 3200 Å region, measurements made above the tropopause (around geographic latitude 36.7°N, longitude 121.7°W at 0045 UT on 1/23/74) generally fit synthetic profiles constructed with 0.3 atm cm of O₃ absorption andBroadfoot's (1972) extra-terrestrial solar irradiance values. However, there are several sections of the solar spectra where the observed intensity is either significantly higher or lower than the calculated value. In addition, several maxima and minima in the observed spectra do not coincide in wavelength with corresponding features in the synthetic profile. Such problems also appear when comparison is made with synthetic profiles based onArvesen et al.'s (1969) extra-terrestrial solar irradiance measurements. These discrepancies may arise from a combination of sources, including errors in laboratory measured O₃ absorption coefficients, the extra-terrestrial solar irradiance values and the presence of other UV absorbing species in the stratosphere.