上海地区地面太阳紫外辐射的观测和分析

通过对上海地区2001～2003年地面太阳总辐射和紫外辐射观测资料的分析表明：（1）上海地区太阳辐射和紫外辐射年总量分别为4487．1MJ／m^2和149．6MJ/m^2。（2）紫外辐射的季节变化特征十分明显，夏半年（4-9月）各月极大紫外辐射强度远大于冬半年（10月～次年3月），7月份最强，12月份最弱。（3）不同天气条件下，紫外辐射日变化显示出明显的差异，晴天强且稳定，多云天气波动较大，阴天则次之。（4）紫外辐射占总辐射的比例（η）也显示冬半年低，夏半年高的分布特征。（5）影响上海地区到达地面紫外辐射的主要因子有：太阳高度角的大小大致决定了到达地面紫外辐射的强弱，两者具有相近的年变化趋势；云、雨等天气类型是影响紫外辐射的重要因子；大气能见度对紫外辐射也有比较明显的影响。

THE OBSERVATION AND ANALYSIS OF THE SURFACE SOLAR ULTRAVIOLET RADIATION IN SHANGHAI

In this article the surface solar total radiation and ultraviolet radiation data observed from year 2001 to 2003 in Shanghai have been analyzed.The results show that:(1) The annual total solar radiation and ultraviolet radiation are 4487.1MJ/m² and 149.6MJ/m² respectively.(2) The inter-monthly distribution of the ultraviolet radiation has obvious seasonal characteristics,higher in summer-half-year(Apr.to Sep.) and lower in winter-half-year(Oct.to next Mar.),highest in Jul.and lowest in Dec.(3) The ultraviolet radiation intensities vary significantly in different weather,it is high and stable in sunny weather,and it fluctuates more in cloudy condition than in overcast.(4) The ratio of Q_UV to Q,called η,shows that its inter-monthly distribution also has seasonal characteristics,higher in summer-half-year and lower in winter-half-year.(5) The principal factors that affect the surface ultraviolet radiation are as follows: The value of the surface ultraviolet radiation intensity is basically determined by the solar altitude angle,both of them have the similar shifting trends in the year;synoptic type such as cloudy and rainy etc.plays an important role in the surface ultraviolet radiation;atmospheric visibility also has relatively obvious influence on the ultraviolet radiation.