Assessing the trend of total column ozone over Ikeja and Warri, Nigeria

This study attempts to assess the trend of total column ozone over Ikeja and Warri in Nigeria. The temporal distribution of tropospheric total column ozone over Ikeja and Warri in Nigeria using the data from total ozone mapping spectrometer (TOMS, Nimbus 7) from 2005 to 2014 were assessed. For both stations, a time series line plot was gotten from the monthly TOMS data and the linear regression method was applied to study the trends in the total column ozone. The P values for each trends for the period of study for both stations were gotten to be 0.1054 (Ikeja) and 0.07177 (Warri) which proved the correlation between the variables used and the result gotten for both stations. The test for homogeneity, Mann-Kendall test and correlation test was done. It was observed that the maximum monthly mean values of total ozone for both stations occurred in February and March respectively while the minimum monthly mean occurred in September and October respectively. The maximum annual mean was observed to be 417DU, while the minimum annual mean was observed to be 256DU for both stations. Total ozone has a seasonal distribution with its maximum occurrence in wet seasons and its minimum occurrence in the dry season for both stations. The trend of total column ozone over both stations showed that it is an increasing trend, while its distribution varies with seasons i.e. the wet and dry seasons for both stations.