Temperature and solar radiation interactions in all six zones of Nigeria

The temperature in a particular geographic area is affected majorly by the amount of solar radiation it receives and its elevation above sea level. Monthly global horizontal solar radiation (in kWh/m(2)/month) and ambient temperature data (in Celsius) according to elevation was obtained from PVGIS Satellite for the six zones in Nigeria over a period of 12 years. With various studies, looking at the solar energy potential of specific locations in a region, this study will seek to give a broader understanding of solar radiation and temperature trends over the major zones of Nigeria. Box plots are used to describe the skewness between solar radiation and temperature. The kernel density estimator (KDE), with Gaussian kernel functions, is employed to generate contour plots for solar radiation and temperature distribution of the zones of Nigeria. Linear regression is then employed to emphasize the relationship between solar radiation and temperature. The box plots indicate that northern states have solar radiation values between 16 and 26 MJ/m(2)/day while the southern states have between 14 and 20 MJ/m(2)/day and linear regression indicates that the solar radiation variation in the north depends less on the temperature than the southern states. The univariate KDE plots and bivariate KDE contour plots show a high positive correlation between the solar radiation and temperature in the southern states and a weak correlation in the northern states of Nigeria. The importance of KDE in analyzing weather data and distribution features are outlined by the results obtained in this study. However, the results obtained here will be useful in decision making related to climate change.