A thesis submitted to the Faculty of Geography, Archaeology, and Environmental Studies University of the Witwatersrand, Johannesburg, in fulfilment of the requirements of the degree of Doctor of Philosophy. 2015. / An imaging DOAS instrument, along with in situ trace-gas and aerosol instrumentation
was deployed on board a research aircraft over the Highveld
region of South Africa, to make regional-scale measurements of nitrogen dioxide
(NO2). The presence of a “hotspot” of NO2 over the Highveld is confirmed.
Case-study estimates of NO2 emission flux were made downwind of
a power station (10 tons.hr−1), a petrochemical plant (36 tons.hr−1) and the
entire Highveld region (395 tons.hr−1).
Vertical profile measurements were used to develop scenarios for a radiative
transfer sensitivity study. From this, suitable air-mass factors for the DOAS
measurements were determined. Comparisons between the airborne DOAS
and satellite instruments show a good agreement where the spatial scales of
the satellite ground pixels and the features in the two-dimensional trace-gas
distribution are matched.
A long-term record of satellite data was analysed. Analysis of radiative
transfer revealed a possible artefact in the adjacent positive and negative
trends evident on the Highveld. A correction to the satellite record for a
seasonal bias was made, and found to be important over biomass burning
regions in Angola and Zambia.
Spatial features in a seasonal model of the satellite record are shown to
correspond with known urban, industrial and biomass burning sources in the
region. Signatures of soil emissions are also detected.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/18516 |
| Date | January 2015 |
| Creators | Broccardo, Stephen Paul |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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