三峡库区太阳能资源基本特征及其演变

利用1961-2007年的日照时数建模计算了三峡库区的太阳辐射，在此基础上对库区的太阳能资源作了全面分析和评价。结果表明：库区年总辐射量介于3200～4400MJ/m²，与德国等太阳能利用大国相当；“下游多，上游少”是资源空间分布的基本特征，且在秋、冬季差异更为明显；资源的年变化具有“夏大冬小”的特点，同时呈典型“双峰结构”，最大和次大峰值分别出现在8月和5月；库区上游太阳能季节差异大，而中、下游四季差异相对较小；库区太阳辐射以散射辐射为主（平均为64%），上游尤其明显；1961-2007年，资源量与直射比均呈明显下降趋势，且在夏、冬季下降尤为显著，分析表明这与轻雾日数和霾日数的增加有关；自20世纪90年代初起，资源量开始回升，有利于库区太阳能的开发利用。

Climatic Characteristics and Long-Term Changes of Solar Energy Resource over the Three Gorges Reservoir Area

Based on dataset of sunshine duration from 1961 to 2007, the solar radiation over the Three Gorges Reservoir Area was estimated, from which, a detailed discussion of its temporal and spatial change was conducted. The results recommend that: Yearly global irradiation over the Three Gorges Reservoir Area lies between 3200 MJ·m~(-2) and 4400 MJ·m~(-2), which is equivalent to Germany and some other European countries; Resource over upstream of the Reservoir Area is richer than downstream, and the difference is significant in autumn and winter; Besides, the resource is better in summer half year than that in winter half, with a double-peak structure on the basis of annual change, and the maximum and sub-maximum peak value thereof appears in August and May respectively; Seasonal difference is remarkable in upstream area, while in downstream it is much smaller; Further more, scattering radiation is the main components of solar radiation over the whole area (64%), especially in upstream; Averaged time series of solar energy showed an obvious decreasing trend from the 1960s to the 1980s, eapecially in summer and winter, and the decline ceased at the beginning of the 1990s, followed by a slight increase to some extent, but haven't returned to the normal level of 1971-2000; The trend of direct radiation ratio change is homoplastic with resource amount; causal analysis indicates that, the increase of light foggy days and haze days may lead to this phenomenon dominantly, and the return of resource amount and direct radiation ratio show an advantage for solar energy application.