Global Solar Radiation Studies Due to Sunshine Hours and Other Meteorological Parameters

Abstract

Multiple linear regression models were developed to estimate the monthly daily Sunshine Hours using four parameters during a period of eleven years (1997-2007) for locations in South Eastern Nigeria. These locations include Uyo (Latitude 5°18'53.7"N), Calabar (Latitude 5°16'07.6"N), Port Harcourt (Latitude 4°56'26.2"N), Warri (Latitude 5°34'21.0"N), Enugu (Latitude 6°27'42.42"N), Owerri (Latitude 5°38'05.1"N). The parameters include Relative Humidity, Maximum and Minimum temperatures, Rainfall and Wind Speed. The result of the correlations show that four variable correlations with the highest value of R for each of the six locations give the best result when considering the error term (RMSE). The models are Uyo (S = -16.876-2.065RF+0.237W+1.278T+0.129RH), Calabar (S = -11.049-6.540RF-0.534W+0.142RH+1.127T), Portharcourt (S = -27.306+0.270RH+1.806T-0.281RH-1.114W), erri (S = 0.677+9.776RF-0.689W-0.057RH+0.900T), Enugu (S = 10.279+5.519RF-0.586W-0.079RH+0.217T), Warri (S = -22.424+0.272RH+1.388T-9.791RF-0.623W). But when considering average values for the six locations, the correlation gives (S = 15.395+0.159RH-0.131T+0.714RF+0.187W). Where RH is Relative humidity, T is the Difference in maximum and minimum temperature, RF is RainFall and W is wind speed. The developed models can be used in estimating Global solar radiation for the six locations under study. It can also be used to estimate Global solar radiation for other places in South Eastern Nigeria where only sunshine records are available.