Abstract: This study approached climate and climate change study using the rainfall distribution over each climatological zone of Northern Nigeria. Nigeria today boasts of not <44 weather observation stations which provide measurement of rainfall amount for different locations across the country. Data were collected for 90 years (1910 to 1999) for all the weather observation stations that falls in the Sahel and Sudan Savannah zones of Nigeria while a subdivision was made to three non-overlapping climatic regimes of 30 years viz 1910 to 1939, 1940 to 1969 and 1970 to 1999. Statistical methods were utilized to justify any such change in the averaged weather. The trend and variability of averaged zonal rainfall was investigated using the probability density function, Wilcoxon Signed-Rank test, Paired Sample test and Mann Whitney test which all form the non-parametric components of the test in order to investigate variations and detect the change points. Results show common change points and transitions from wet to dry (downward shift) and vice versa in both zones. Statistical tests performed on the data show that rainfall variation over the Sahel is significant (p<0.05) between pairs of regimes (1st and 3rd, 2nd and 3rd) while it is not significant (p<0.05) between 1st and 2nd. Over the Sudan, rainfall variability between climate regimes were not statistically different at 95% confidence interval. Suggestions were therefore made at the end of the study on the use of the contained information for socio-economic improvement and agricultural development of the zones.

The suitability of two coastal stations in Nigeria for wind energy generation is presented in this study. To estimate the wind speeds at the desired height 70 m for standard wind turbine, two methods; namely power law relationship and diabatic evaluation have been considered. It was found that the diabatic evaluation method performed better because certain physical conditions of farm site are included in the method. Thus when potential site data are not available diabatic method can provide a good approximation of wind speeds. Comparing the energy potential of the two coastal stations, Lagos and Calabar in this study, it was found that Lagos has stronger wind speeds than Calabar especially during peak periods. The atmospheric condition most suitable to obtain maximum wind speeds was also found to be during stable condition. Stable condition occurs mostly in the night time.