Analysis of Trends and Variations of Monthly Mean Wind Speed Data in Nigeria (original) (raw)

Trends and variations of monthly mean wind speed data in Nigeria were analyzed. The data used were obtained from the Nigerian Meteorological Agency, Oshodi, Lagos. 20 land anemometer stations across various ecological zones and climatic belts in Nigeria were selected for the analyses. The data length spanned from 1951-2012 with some variations in data length across the stations. Statistical techniques used for the analyses are Mann-Kendall's rank correlation tests, simple linear regression, Pearson's product moment correlations, time series plots, descriptive statistics and bar charts. The Mann-Kendall's test results indicate dominant declining trends over the period. 11 stations show downward trends, with 8 showing significant downward trends at the 1% level. 9 stations show upward trends, with 7 showing significant upward trends at the 1% level. The Pearson's product moment correlation coefficients indicate that some of the station pairs have negative correlations significant at the 1% and 5% levels. Other station pairs show significant positive correlations at the 1% and 5% levels while other station pairs show negative and positive correlations that are not significant at the chosen significance levels. The seasonal variations represented in the bar charts indicate that spring is the windiest period in most of the stations while autumn dominates the calm period in most stations across Nigeria. Majority of the stations show high coefficients of variation which increases northwards along with the monthly mean wind speeds. The results have implications for air quality management, modeling of wind speed regimes, planning and financing of wind energy and heat and moisture transfer between the earth's surface and the atmosphere.