Estimation of solar radiation using Angstrom-Prescott model and interpolation of empirical coefficients in Thailand

Angstrom-Prescott model, defined by , was applied to estimate solar L so J radiation for 11 meteorological stations in Thailand. In this research, the empirical coefficients ('a' and 'b') were calculated by using the least square model. Statistical values, i.e., root mean square error (RMSE) and correlation, were analyzed the model ability in estimating solar radiation by compared with the measurement. The empirical coefficients overall Thailand were interpolated by using geographic information system (GIS). This technique can be calculated for estimation of solar radiation in every region in Thailand. In the results, the statistical tests show the ability of Angstrom-Prescott model to estimate solar radiation in Thailand and the least square method is suitable for computing empirical coefficients.