Abstract:In order to study the temporal-spatial distribution of solar radiation (Rs) in Northwest China, daily Rs of 16 stations in Northwest China from 1961 to 2015 were calculated by ?ngstr?m-Prescott (A-P) model, and cloud model was used to describe the temporal-spatial distribution of Rs in Northwest China. To obtain the best parameters calibrated method and assess its adaptability, Northwest China was divided into four areas. Ⅰ area included northern Xinjiang, middle and west section of Hexi Corridor of Gansu, central and northern Ningxia, western Inner Mongolia. Ⅱ area included southern Xinjiang. Ⅲ area included Qinghai. Ⅳ area included southeast Gansu, southern Ningxia, Guanzhong and northern Shaanxi. Daily climatic data radiation (Rs) and sunshine hour (n) of 16 stations from 1995 to 2015 were used to calibrate A-P model parameters, and four different parameters calibrated methods for A-P model were used, including monthly (M1), seasonally (M2), bi-annualy (M3) and annually (M4), in which high precision and simple calculation method for each area was finally selected to calculate Rs. The results showed that the fitting results of four parameters calibrated methods conformed the measured values well both in daily and monthly scales. RMSE and nRMSE of four parameters calibrated methods changed little. The values of t statistic showed that there was no difference among the three methods (M1, M2 and M3) in use of data calculation in Ⅰ area and Ⅲ area, no difference between the two methods (M1 and M3) in use of data calculation in Ⅱ area, no difference between the two methods (M1 and M2) in use of data calculation in Ⅳ area. When cloud model was used to analyze the temporal-spatial distribution characteristics of Rs in Northwest China, as a consequence, there was good homogeneity but poor stability of Rs in Ⅰ area in the time. There was good homogeneity and stability of Rs in Ⅱ area and Ⅲ area in the time. There was poor homogeneity and stability of Rs in Ⅳ area in the time. Besides, spatial distribution of Rs in Northwest China was uneven. Rs of the four seasons in Ⅲ area (Qinghai Province) was larger than those of other areas. In general, the homogeneity and stability of Rs in the space was worse than that in the time. The results can be used to construct a complete Rs time series in Northwest China and provide a scientific reference for the study of temporal-spatial distribution characteristics of Rs in Northwest China.
