العلاقة بين الاشعاع الشمسي الكلي و فترة سطوع الشمس لمحطات مختارة في العراق

A new relationship between sunshine duration and global solar radiation were investigated through the analysis of data on monthly global solar radiation and hours of bright sunshine for three meteorological stations in Iraq (Baghdad, Mosul and Basra) during the period 1971-2000 .linear regression was used to fit the Angstrom equation to estimated values were compared with measured values in terms of root mean square error (RMSE), mean bias error (MBE) and mean percentage error (MPE). The model fitted the data adequately and can used to estimate values monthly means global radiation from sunshine durations hours. A good agreement was observed between the measured and estimated values of our model especially in Mosul station.