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Lusaka, Zambia, during SAFARI‐2000: Convergence of local and imported ozone pollution
Author(s) -
Thompson Anne M.,
Witte Jacquelyn C.,
Freiman M. Tal,
Phahlane N. Agnes,
Coetzee Gert J. R.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl015399
Subject(s) - ozone , haze , geography , pollution , environmental science , climatology , meteorology , geology , ecology , biology
In August and September, throughout south central Africa, seasonal clearing of dry vegetation and other fire‐related activities lead to intense smoke haze and ozone formation. The first ozone soundings in the heart of the southern African burning region were taken at Lusaka, Zambia (15.5S, 28E) in early September 2000. Maximum surface ozone was over 90 ppbv and column tropospheric ozone exceeded 50 DU. These values are higher than concurrent measurements over Nairobi (1S, 38E) and Irene (25S, 28E, near Pretoria). At least 30% of Lusaka surface ozone appears to be from local sources. A layer at 800–500 hPa has ozone >120 ppbv and originates from trans‐boundary recirculation. Starting out over Zambia, Angola, and Namibia, ozone‐rich air travels east to the Indian Ocean, before heading back toward Mozambique, Zimbabwe and Zambia. Thus, Lusaka collects local and imported pollution, consistent with its location within the southern African gyre.