一、前言 太阳辐射的分布和变化是决定气候形成的基本要素,又是太阳能工程设计和农业生产潜力估算的重要依据。但是有限的辐射测站不能提供足够的资料,因此太阳辐射的计算及其方法的改进一直是许多研究者注意的目标。

Various geographical and climatological factors that affect solar radiation reaching the ground are analysed. Based upon the screen method, several convenient factors representing shady and transparent degree of the sky are determined. Then, a set of empirical equations suitable for the continental region of China are established by means of the stepwise regression method to estimate the monthly or monthly average daily total, direct and diffuse solar radiation.The results of the author’s tests indicate that the accuracy of these unified equations is no less than that of regional equations. So, by using these unified equations, it is possible to overcome the inconvenience in the regional calculation. These equations embody the decreasing effect of fly ash and smoke screen on direct solar radiation as "well as their enhancing effect on diffuse solar radiation. It seems that fly ash and smoke screen do not have apparent influence on total solar radiation. Bela-tive sunshine is still the dominant factor affecting total and direct solar radiation. Two supplementary factors significantly affecting total solar radiation are elevation and water vapour. They roughly reflect the atmospheric transparency affecting total solar radiation in winter half year. The seasonal variation (especially between winter and summer) of these equations shows quantitatively the effect of the China’s monsoon climate on solar radiation.