Remote sensing of the atmosphere using a Fourier transform infrared spectrometer with the sun as a source of radiation allows the measurement of vertical column amounts of trace species in the atmosphere. This technique has been applied during the winters of 1994/95 and 1995/96 from a mid-latitude site at Rutherford Appleton Laboratory (RAL), Chilton, Oxon and results from this research are discussed in this thesis. An overview of the theory of infrared spectroscopy is presented followed by a description of the spectrometer used to record the measurements. A 'forward model' that has been developed to analyse the measurements and the retrieval technique for reducing the measurements to vertical column amounts of HF, HNO<SUB>3</SUB>, HCI and C1ONO<SUB>2</SUB> is discussed. Variations in vertical column amounts of mid-latitude HF measured during the 1994/95 winter can be understood as a results of variations in tropopause height and movement of air from higher and lower latitudes over the measuring site. Columns of HC1 and C1ONO<SUB>2</SUB> indicate that chemically processed air with a depleted HC1 column and enhanced C1ONO<SUB>2</SUB> column were measured on the 23<SUP>rd</SUP> January 1995, associated with the polar vortex which meteorological analyses indicate was above RAL on this day. Similar measurements performed by a group from the National Physical Laboratory (NPL) from Aberdeen show depletions of both HC1 and C1ONO<SUB>2</SUB>, indicating that there is a strong latitudinal gradient in the C1ONO<SUB>2</SUB> column at the edge of the polar vortex. Comparisons with a three-dimensional off-line chemical transport model (CTM) show that dynamical variability in the mid-latitude stratosphere is well represented, but that chlorine partitioning and the effect of seasonal timescale diabatic descent at high latitudes are less accurately calculated.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:597145 |
| Date | January 1999 |
| Creators | Burton, Michael Richard |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.repository.cam.ac.uk/handle/1810/284055 |
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