Variation of the Earth’s Irradiance over Some Selected Towns in Nigeria

Document Type : Original Article


1 Physics and Solar Energy Programme, College of Agriculture, Engineering and Science, Bowen University, Iwo, Osun State, Nigeria

2 Statistics Programme, College of Agriculture, Engineering and Science, Bowen University, Iwo, Osun State, Nigeria


The extraterrestrial radiation is the solar radiation received at the top of the earth’s atmosphere on horizontal surface. This quantity over selected stations in the tropics was investigated. Daily data of the extraterrestrial radiation on the earth horizontal surface for the year 2018 for stations: Iwo, Abuja, Enugu, Port-Harcourt, Sokoto and Maiduguri obtained from the archive of HelioClim website were analyzed using MATLAB and Statistical Packages for Social Science (SPSS Version 20.0) to estimate the extraterrestrial radiation of the station considered. The results of the MATLAB revealed that the value of the coincidence is  across all stations. In January, the values between 15 - 20 peaks were observed in the year with the Irradiation ( ) and the maximum ( ). The results revealed the Root Mean Square Error RMSE for Sokoto (139.99), Abuja (162.72), Iwo (177.07), Maiduguri (171.34), Enugu (191.07), Port-Harcourt (212.27). The results also revealed that quadratic trend equation which accounted in the range 95.9% - 41.9%. The results then concluded that Sokoto and Maiduguri have the highest solar Irradiance as revealed by the result. 


1.    Evans, J. P., Meng, X., & McCabe, M. F., 2017, Land surface albedo and vegetation feedbacks enhanced the millennium drought in south-east Australia, Hydrology and Earth System Sciences, 21(1): 409–422.
2.    Aweda, F. O., Akinpelu, J. A., Falaiye, O. A., & Adegboye, J. O., 2016, Temperature Performance Evaluation of Parabolic Dishes Covered with Different Materials in Iwo, Nigeria, Nigerian Journal of Basic and Applied Sciences, 24(1): 97.
3.    Audu, M. O., & Isikwue, B. C., 2014, Estimation Of The Albedo Of The Earth’s Atmosphere At Makurdi, Nigeria, International Journal of Scientific & Technology Research, 3(4): 375–380.
4.    Taherzadeh, M. J., & Karimi, K., 2007, Acid-based hydrolysis processes for ethanol fromlignocellulosic materials: A Review, BioResources, 2(3): 472–499.
5.    Mohandes, M., Rehman, S., & Halawani, T. O., 1998, Estimation of global solar radiation using artificial neural networks, Renewable Energy, 14(1–4): 179–184.
6.    Trajković, S., Todorović, B., & Stanković, M., 2001, Estimation of FAO Penman c factor by RBF networks, FACTA UNIVERSITATIS Series: Architecture and Civil Engineering, 2(3): 185–191. Retrieved from
7.    Reddy, K. S., & Ranjan, M., 2003, Solar resource estimation using artificial neural networks and comparison with other correlation models, Energy Conversion and Management, 44(15): 2519–2530.
8.    Aweda, F. O., Oyewole, J. A., Falaiye O. A., & Opatokun, I. O., 2018, Estimation of Evaporation rate  in Ilorin Using Penman Modified Equation,  Zimbabwe Journal of Science and Technology, 13: 20–25. Retrieved from
9.    Baumgartner, J., Höltinger, S., & Schmidt, J., 2018, Evaluation of technical modelling approaches for data pre-processing in machine learning wind power generation models, In 20th EGU General Assembly, EGU2018, Proceedings from the conference held 4-13 April, 2018 in Vienna, Austria (Vol. 20), pp. 2018–14305. Retrieved from
10. Okundamiya, M. S., & Omorogiuwa, O., 2015, Viability of a Photovoltaic Diesel Battery Hybrid Power System in Nigeria, Iranian (Iranica) Journal of Energy and Environment, 6(1): 5–12.
11. S. Jain, & U. Chandrawat, 2018, Photocatalytic Degradation of Sulfamethoxazole in Visible Irradiation Using Nanosized NiTiO3 Perovskite, Iranian (Iranica) Journal of Energy and Environment, 9(1): 31–40.
12. Rahman, M. R., Hossain, M. S., Shehab Uddin, S., & M Ibrahim, A. S., 2019, Fabrication and Performance Analysis of a Higher Efficient Dual-Axis Automated Solar Tracker, Iranian (Iranica) Journal of Energy and Environment, 10(3): 171–177.
13. Babar, B., & Boström, T., 2016, Estimating solar irradiation in the Arctic, Renewable Energy and Environmental Sustainability, 1(34): 1–5.
14. Barka, Z. M., Lealea, T., & Tchinda, R., 2018, Estimation of the earth’s albedo over some selected area the Republic of Chad, International Journal of Physical Research, 6(2): 64–69.
15. Babatunde, E., Falaiye, O., & Uhuegbu, C., 2005, Simulated reflected SW-radiation and its characteristic variation at Ilorin, Nigeria, Nigerian Journal of Physics, 17(2): 193–201.
Retrieved from
16. Iqbal, M., 2012. An introduction to solar radiation. Elsevier.
17. Spencer, J., 1971, Fourier series reprensentation of the position of the sun, Search, 2(5). Retrieved from
18. FAO, 2013. The Fao Penman-Monteith. Chapter 3 - Meteorological data. In Webpage 1–39.
19.           Aweda, F. O., & Samson, T. K., 2020, Modelling the Earth’s Solar Irradiance Across Some Selected Stations in Sub-Sahara Region of Africa, Iranian (Iranica) Journal of Energy & Environment Journal Homepage: IJEE, 11(3): 204–211.