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Title: The determination and evaluation of stratospheric ozone
Author: Bosch, R. A.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2002
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Extensive research has been carried out to fully understand the mechanisms involved in the destruction of large amounts of ozone in the Arctic region. For this purpose, a novel light-weight, relatively cheap and low-powered ozone instrument has been developed for measurements in the lower stratosphere on long-duration balloon flights in the polar vortex, and is presented here. The instrument contains a solid-state semi-conducting sensor with a heated tungsten oxide surface. Adsorption of ozone onto the surface increases the resistance of the sensor, so that the value of the resistance gives a direct indication of how much ozone is present. The instrument has flown alongside ozone sondes to test its performance. The free flow configuration, with the sensor placed directly into the air flow caused by the ascent of the balloon, has shown that the instrument measures structures in the ozone profile better than the ozone sonde. Discrepancies between the instrument and sonde measurements are mainly related to changes in the diffusion near the sensor surface at lower pressures, as indicated by laboratory experiments. Smaller effects are related to changes in humidity and flow rate. A quantitative procedure, with a single collaboration fully explaining the sensor behaviour prior to a flight, is within reach. The behaviour of the long-duration balloon has been modelled, providing a test for the accuracy of a radiative transfer model and its sensitivity to several input variables. The radiative cooling rates in the lower stratosphere are a measure of the descent, which in turn determines the amount of ozone transported into the region with the highest destruction rates.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available