Publication Date:
2019-07-18
Description:
In early September, throughout south central Africa, seasonal clearing of dry vegetation and the production of charcoal for cooking leads to intense smoke haze and ozone formation. Ozone soundings made over Lusaka in early September 2000 recorded layers of high ozone (greater than 125 ppbv at 5 km) during two stagnant periods, broken by a frontal passage that reduced boundary layer ozone by 30%. During the 6-day measurement period, surface ozone concentrations ranged from 50-95 ppbv and integrated tropospheric ozone from the soundings was 39-54 Dobson Units (note 1.3 km elevation at the launch site). A stable layer of high ozone at 2-5 km was advected from rural burning regions in western Zambia and neighboring countries, making Lusaka a collection point for transboundary pollution. This is confirmed by trajectories that show ozone leaving Angola, Namibia, Botswana and South Africa before heading toward the Indian Ocean and returning to Lusaka via Mozambique and Zimbabwe. Ozone in the mixed layer at Lusaka is heavily influenced by local sources.
Keywords:
Meteorology and Climatology
Type:
Joint CACGP/IGAC 2002 Symposium; Sep 18, 2002 - Sep 25, 2002; Heraklion; Greece
Format:
text
