Authors : K.O. Ogunjobi , V.O. Ajayi and I.A. Balogun
Abstract: General characteristics and trends of tropospheric total column ozone content were investigated using data available at the World Ozone and Ultraviolet Data Centre (WOUDC). Observations are made at four different stations in Africa namely Nairobi (Lat.1° 16` S; Long. 36° 48` E), Lagos (Lat. 6° 27` N ; Long. 3° 24` E ) , Cairo (Lat. 29° 52` N; Long.31° 20` E) and Aswan (Lat. 24° 05`N; Long.32° 56` E). The annual mean total column ozone estimated were 254.35 ± 8.25DU, 254.89 ± 6.07DU, 290.89 ± 6.27DU, and 270.28 ± 4.94DU for Nairobi, Lagos, Cairo and Aswan respectively. An increasing trend in total column ozone of 0.89DU / yr (or 0.35% year-1) was observed at Nairobi while Lagos recorded a trend of 1.02DU/yr (or 0.40% year-1). A similar but slightly positive trends of 0.10DU /yr (or 0.04 % year-1) and 0.04DU/yr (or 0.02 % year-1) were observed for Cairo and Aswan respectively. The annual value of column ozone reported at Cairo, are lower in the 1990s than in the previous decade: total ozone amounts are 3.9�0.02 lower in 1990s than those observed in the 1980s.
K.O. Ogunjobi , V.O. Ajayi and I.A. Balogun , 2007. Long-Term Trend Analysis of Tropospheric Total Column Ozone in Africa. Research Journal of Applied Sciences, 2: 280-284.