%0 Journal Article %T SEASONAL VARIATION of the SPECTRAL IRRADIANCE for the PROVINCE of MU£¿LA %A Murat Kabak£¿£¿ %A R¨¹£¿t¨¹ Eke %J - %D 2018 %X Calculation of the amount of energy from the sun as the energy source of the world is very important in terms of determining the efficiency of photovoltaic (PV) systems. At air mass zero solar spectral irradiance values have received a great deal of attention in recent years and are given in the wavelength range 0.2-4.0 ¦Ìm. The amount of incoming sunlight can be calculated with different mathematical models. In this study, a mathematical modelling using SPCTRL 2 program will be discussed. The model has many variables in determining the quantity of sunlight coming in the atmosphere. With this model, the amount of solar energy falling on any on spot on the Earth¡¯s surface can be calculated and graphically modelled. In this study, direct, indirect and total (global) solar energy amounts coming from horizontal and sloping surfaces for Mugla were calculated depending on the wavelength. Horizontal and 30¡ã inclined surfaces were calculated separately for winter, spring, summer and autumn seasons for Mu£¿la Province. As a result, the amount of solar radiance for Mu£¿la province was determined by mathematical modelling and the general conditions for the establishment of suitable photovoltaic system were determined %K G¨¹ne£¿ £¿£¿£¿n£¿m£¿ %K spectral da£¿£¿l£¿m %K g¨¹ne£¿ enerjisi %K referans modelleme %U http://dergipark.org.tr/muglajsci/issue/39930/455566