中文摘要：

用固城试验站观测的紫外UV—B辐射（QUV-B）和总辐射（Q）的资料，对紫外UV-B辐射特征及生态效应进行分析。结果表明，紫外UV-B辐射年变化与太阳总辐射的变化规律基本一致，均呈波动的单峰型曲线，冬季1月份为全年最低，夏季6月份为全年最高，春末5月份出现低值。各季典型晴天QUV-B和Q的日变化均呈明显单峰型曲线，日出后随太阳高度角增加而增大，早晚低，中午高。各季典型晴天紫外UV-B辐射占太阳总辐射比值（ηUV-B）在0．15％-0．30％之间。其日变化在冬季和秋季呈浅“U”字型，早晚略高，而春、夏的日变化较平缓，与青藏高原的变化规律不一致。从紫外UV-B辐射增强对生物影响进行了评述，目前华北平原北部地区紫外uv—B辐射量小于1．6w／m^2，低于对人和动物安全标准2W／m^2，一般低于造成威胁人和动物的风险水平。

英文摘要：

In this paper, the characteristics of the ultraviolet -B radiation （Quv-B） and its ecological effects are analyzed by using the ultraviolet -B radiation （QUV-B） and global radiation （Q） data in the Gucheng Experimental Station. The results show that annual changes of QUV-B and Q present a shape of fluctuated single-peak curve, in which the daily minimum appears in morning and evening, and daily maximum appears at noontime. The annual minimum of radiation and the uhraviolet-B radiation appears in January of winter and the annual maximum appears in June of summer. In the late spring, the radiation is a little lower. The uhraviolet-B radiation is 1.53 W/m^2 in summer and is 0.90 W/m^2 in winter. QUV-B and Q increase with the increase of solar altitude and it is low in the morning and high at noontime. At the same time, the daily change of the ratio of Quv-a to Q （ηUV-B） is raged from 0.15% to 0.30%. In addition, the daily change of that in winter and autumn presents a ＂U＂ shape, which is higher in morning and evening than that at noontime, but it is not obvious in spring and summer, ηUV-B is a little higher in winter than that in autumn, ranged from 0.21% to 0.28% and 0.19% - 0.24% respectively, while ηUV-B are more lower in spring and summer ranged from 0.17% to 0.23%. The tendency in North China Plain is different from that in the Tibet plateau. At present, the studies of the uhraviolet-B on ecologic effects also have focused on qualitative and semi-qualitative scale. Less studies have made on the effects of the ultraviolet-B on crop growth. So, for quantitatively evaluating the effects of the uhraviolet-B on crop growth, we must do some quantificational studies. In addition, the fact that ozonosphere depletion results in the increase of the ultraviolet in earth surface ought to be fully recognized. In the sunshine days of the four seasons in Gucheng Experimental Station, the ratio of the ultraviolet- B to global radiation often are less than 0.33 %, and the intensity of the uhraviolet-