Estimating and Classification Solar Radiation On Horizontal Surfaces Using Climatic Parameters in GIS (Case Study: East Azarbaijan province)

Abstract Solar radiation reached to ground as one of the essential factors for studies of water resources, environment, agriculture and vegetables coverage, architectural harmony with the climate, designing the systems for use of clean energy and other numerous cases, has a wide application. This factor not be measured in all meteorological stations and therefore presented a lot of empirical methods for it estimating by use the meteorological, astronomical and geographical parameters. The purpose of this study is estimating the total amount of radiation reached to horizontal surface using climate parameters (minimum, maximum and average temperature, minimum humidity, sky cloudy, sunny hours) and it’s classification in Eastern Azarbaijan province. Thus, the measured monthly data of solar radiation in Tabriz station during 2001 to 2006 years were used for modeling and the climatic data of 6 synoptic stations in the province during 1987 to 2007 were used to estimate the amount of radiation. By calculating multiple regression coefficients the accuracy of the model Were analyzed Then, required layers in GIS environment were created and by apply the regression model coefficients in created layers, the total amount of radiation an horizontal surfaces in the province was estimated. According to the distribution of monthly radiation maps at the province width, the radiation pattern in the province divided to four period: winter season, spring, summer and autumn. The lowest radiation amount is in January and most radiation amount is in June. Distribution of annual radiation in state shows the reduction process from the South West to the north and northeast. Average annual radiation in the province, is 4244 W/m2/day. Amplitude changes of annual radiation in province is 443 W/m2/day and it’s spatial variability coefficient is 2 percent.