利用卫星资料估算我国西北地区直接辐射

在缺乏直接辐射、云量、日照时数等地面观测资料情况下,如何正确估算太阳直接辐射对太阳能合理开发利用有重要意义。利用NCEP/NCAR再分析资料、EOS-AURA卫星和FY-2C气象卫星反演资料,采用一个改进的宽带辐射传输模型对我国西北5个地面辐射站点2006年和2007年直射日曝辐量进行了估算。模型首先在Bird模型基础上对晴空条件下的太阳直接辐射进行了计算,然后结合FY-2C气象卫星总云量和云类反演数据,引入了一个线性方程,对实际天气状况下的直射日曝辐量进行了计算。结果表明:5个站点模拟的直射日曝辐量与实测值均存在较好一致性,评价效率系数NSE介于0.68~0.8,而对月均直射日曝辐量的模拟结果则显示模型在4-10月的估算精度要高于11-3月结果。

Estimation Direct Irradiance Based on Several Satellite Data in Northwest China

Accurate knowledge of the geographical distribution of the direct irradiance over an area of interest is important for the solar energy assessment and management. Because stations for measuring solar irradiance, cloud and sunshine hours are scarce in Northwest China, a method must be developed to estimate the direct radiation. An enhanced broadband direct irradiance model based on several satellite data, such as NCEP/NCAR data, the Chinese FY-2C geo-stationary meteorological satellite data and the NCEP/NCAR Reanalysis 1 Project data sets, is presented in this paper. The method, originated from Bird clear-sky model, firstly calculates the radiative transmittances for clear skies, and then calculates direct irradiance for cloudy conditions. To calibrate the model and evaluate its performance, five ground stations in Northwest China, where the direct irradiance are routinely measured in 2006-2007, are used for model calibration and verification. The simulation result shows that the estimated daily direct irradiance correlates well with measured direct irradiance at the five stations, with the Nash-Sutcliffe Cofficient of Efficiency(NSE) 0.68-0.8. The performance of the monthly average daily direct irradiance reveals that the result from April to October is better than that from November to March.