An Empirical Model for Calculating Monthly Average Daily Global Solar Radiation Based on Temperature for Five Cities of Different Climates in Iraq

Surface temperature of the Earth (land, oceans and atmosphere) is affected by local factors that control the climate. This is contrary to what happens outside the gaseous envelope of the planet, where heat is transmitted by the presence of solar radiation. The adopted model in this study has been applied in China [1], values of maximum and minimum temperatures in five cities in Iraq that differ in their climates, were used to calculate the monthly average of global solar radiation by means of four different equations. The results of the comparison between the real values and calculated rates of solar radiation had showed some errors. The evaluated empirical coefficients in the four equations were dealt with as a boundary condition for each equation separately, later on the errors were eliminated as much as possible to calculate new suitable empirical coefficients, which re-applied to re-calculate the new the monthly average of global solar radiation. The significance of his model lies in the ability to calculate the monthly average daily global solar radiation of the cities where only the temperature values are available values.