The Influence of Some Atmospheric Phenomena on Total Ozone Concentration over the Tropics

The influence of some atmospheric phenomena such as the Quassi Biennial Oscillation, the El Nino Southern Oscillation (ENSO) and the extratropical suction pump action on total ozone concentration over the region spreading from latitude 30 south to 30 north were studied using o o satellite data from 1997 to 2002. These phenomena were observed to contribute significantly to the variability of ozone concentration over the region. The region was divided into twelve latitudinal zones of 5 each. The equatorial zones 5 S-5 N recorded high percent variability above 6.5% in at least nine o 0 0 months of the year. This may be attributed to the extra-tropical suction pump action been strongest over the two zones closest to the equator. Zone 30 S-25 S recorded a high stability in ozone 0 0 concentration in March in the six years studied with average variability of 0.7%. The six northern zones recorded higher values of annual coefficient of relative variation (ACRV) of ozone than their southern counterparts in the six years studied with average value of 5.0% and 3.0% respectively. There was a peculiarity in the ozone concentration in 1998, which was a year of El Nino Southern Oscillation (ENSO) occurrence. The ACRV of ozone concentration almost doubled the average zonal values especially at the southern tropics. At zones 5 S 15 S, the average ACRV in 1998 was 4.3% 0 0 while the average ACRV for the other five years studied was 2%. In the northern tropics, the values of ozone concentration at zones 0 -15 north were very close with a correlation of 0.99, between 0 0 September to December of the years 1997, 1999 and 2002, while there were noticeable degrees of disparities in the other periods studied. This was attributed to the effect of quasi-biennial oscillation (QBO) at the region in these periods.