Measurements of minor constituents which affect ozone concentrations in the stratosphere

Thesis



The chemistry of stratospheric ozone is discussed and particular consideration is given to the role of chlorine compounds and to the impact of human activity on the ozone layer. An account is given of the methods used by other researchers to measure hydrogen chloride (HC1) in the stratosphere and their results are summarized.

The pressure modulator radiometer (PMR) is an instrument which can be used to make remote measurements of atmospheric temperature and composition by sensing the radiation transmitted by or emitted from an atmospheric path containing gases with absorption bands in the infra-red. A balloon-borne PMR has been used to detect the absorption of solar radiation by the fundamental vibration-rotation band of HC1 at 3.5 micrometres. Using a limb scanning technique, the mixing ratio profile of HC1 has been measured over the height range, 16 to 39 km.

It is shown that the amount of HC1 in an atmospheric path can be related to the PMR signals using a line-by-line method. The theory is developed in sufficiently general terms for it to be applicable to line-by-line calculations for many other gases with absorption bands in the infra-red. Consideration is given to the modelling of PMR measurements of transmission and emission both in the atmosphere and in the laboratory.

The instrument used to measure HC1 is described in detail. The problems associated with the interpretation of the signals are discussed and an account of the instrument's laboratory testing is given. The reduction of the balloon flight data is described and the method used to retrieve the mixing ratio profile from the PMR signals is presented.

Authors: Eyre, J

• Publication date: 1978
• DOI: 10.5287/ora-9exjjpkpy
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Subjects: Ozone layer; Atmospheric chlorine compounds