Tropospheric ozone plays an important role in the atmosphere especially towards
climate change and air quality. In this study, characteristics of tropospheric ozone
over the South African Highveld are investigated using the ozonesonde data collected
at Irene weather station (25.9°S, 28.2°E, and 1523 m asl) for the period 1990 to 1993
and 1999 to 2003. It was found that synoptic systems have an effect on the vertical
distribution of tropospheric ozone. Ozone stratification appeared during anticyclonic
conditions as displayed by a continental high ozone profile. During the ridging high,
low ozone concentrations are observed with a strong ozone gradient between 10 and
12 km. Ozone enhancement appeared in the lower altitudes, <4 km, in both the
ridging high and the westerly disturbance ozone profiles. Ozone profiles exhibited
higher ozone concentrations during the westerly wave conditions. Tropospheric
ozone over the South African Highveld region follows a clear annual cycle with
lower ozone concentrations observed during autumn and higher ozone concentrations
during spring. Summer ozone profiles had high ozone concentrations from the earth’s
surface up to 9 km compared to winter ozone profiles. However, winter ozone
profiles exhibited higher ozone concentrations than summer ozone profiles and they
were characterised by a strong ozone gradient at 12 km. Ozone profiles obtained
during the Southern African Fire-Atmosphere Research Initiative conducted in 1992
(SAFARI-92) displayed lower ozone concentrations than ozone profiles from the
Southern African Regional Science Initiative conducted during 2000 (SAFARI-
2000). Therefore, it is apparent tropospheric ozone over the South African Highveld
has increased over the past decade.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/5578 |
| Date | 29 August 2008 |
| Creators | Phahlane,Agnes Ngwanakgari. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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