Quantifying Stratospheric Chlorine Chemistry by the Satellite Spectrometers GOME and SCIAMACHY

• Main Author: Kühl, Sven
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2005
• Subjects: 530; 530 Physics; Antarc*; Antarctic; Arctic
• Online Access: https://archiv.ub.uni-heidelberg.de/volltextserver/5664/; https://archiv.ub.uni-heidelberg.de/volltextserver/5664/1/Sven_DISS.pdf; https://doi.org/10.11588/heidok.00005664; https://nbn-resolving.org/urn:nbn:de:bsz:16-opus-56645

Since the mid eighties of the past century, an almost complete destruction of the ozone layer above the Antarctic in springtime (and to a lesser extent also above the Arctic) is observed, which is caused by the release of atomic chlorine and bromine from anthropogenic halogen compounds. Due to the fast phase out of the production of CFCs, the increase of the stratospheric chlorine loading could be slowed down, and the recovery of the ozone layer is expected around the year 2050. However, the impacts on atmospheric chemistry, the climate and the biosphere are considerable. By differential optical absorption spectroscopy (DOAS) various molecules with characteristic absorption spectra can be detected simultaneously in the atmosphere, among them also many halogen compounds. In this thesis, measurements of the satellite spectrometers GOME and SCIAMACHY were evaluated for the atmospheric trace gas chlorine dioxide (OClO) and analysed with respect to their relevance for the polar stratospheric ozone chemistry. OClO is an important indicator for stratospheric chlorine activation, the conversion of the mainly anthropogenic chlorine from its ozone- inert reservoir compounds into ozone destroying (active) species. This activation of chlorine takes place by heterogeneous reactions on polar stratospheric clouds, which may be formed under the extremely cold stratospheric temperatures prevailing in polar nights. In this thesis, measurements of the OClO column density by GOME and SCIAMACHY during the polar winters 1995-2005 are quantitatively related to the meteorological conditions, the effect on the ozone column and the interaction with other stratospheric trace gases. The measurements by SCIAMACHY in the limb geometry can be inverted to vertical profiles by calculation of the radiative transfer, which increases the information content with respect to a measurement of the column density essentially. In this thesis, algorithms for the retrieval of vertical profiles of OClO, ozone, BrO and NO2 were developed and first results ...