Retrieval of stratospheric ozone density profiles from OSIRIS scattered sunlight observations.

摘要

A major Canadian contribution to Global Change research involves a novel satellite instrument for monitoring stratospheric ozone concentrations. The instrument, known as OSIRIS (the Optical Spectrograph and InfraRed Imager System), was designed to measure ozone densities using a powerful new technique based on measurements of sunlight scattered by the atmosphere. This dissertation reports the first global distributions of ozone obtained from the OSIRIS measurements made during the first few months of operation.; The method used to retrieve the ozone densities from the OSIRIS observations follows that of Flittner et al. [2000] and McPeters et al. [2000]. The method is based on the analysis of normalized limb radiance profiles measured at wavelengths in the centre and the wings of the Chappuis-Wulf absorption bands of ozone. As part of this thesis work a non-linear Newtonian iteration version of Optimal Estimation [Rodgers , 1976; 1990] has been coupled with the LIMBTRAN multiple scattering radiative transfer model described by Griffioen and Oikarinen [2000] in order to analyze the OSIRIS limb radiance measurements.; An extensive set of OSIRIS limb observations was collected during August 2001, when Odin started normal operation and was observing in the northern hemisphere. The analysis of all limb scans that are available for August has yielded stratospheric ozone density profiles that are in excellent agreement with the current knowledge of the global morphology of ozone. The tropospheric ozone column densities have been inferred from the OSIRIS stratospheric ozone densities using a residual approach and the total ozone columns measured by the Total Ozone Mapping Spectrometer (TOMS) on the Earth Probe (EP) satellite. These tropospheric estimates are in reasonable agreement with those derived by Fishman et al. [1990].; At the end of October 2001 OSIRIS was able to make observations in the southern hemisphere in the Antarctic ozone hole region. The first extensive observations of the ozone profile in the ozone hole are presented and it is shown, from November 2001 data, that OSIRIS is capable of accurately monitoring the evolution of the 3-dimensional structure of the Antarctic ozone hole.; The analysis of the OSIRIS observations has shown that global ozone profiles with high accuracy and high vertical resolution (1–2 km) can be obtained using this new technique (Abstract shortened by UMI.).