中文摘要：

利用广西20个气象观测站点1957—2001年EФ20小型蒸发皿的实测水面蒸发资料，采用变差系数和年际极值比分析蒸发的年际变化特征，应用累积滤波器法定性分析蒸发量的年际变化趋势，Kendall秩次相关法定量分析蒸发量的年际变化趋势及其显著性，Mann-Kendall非参数统计检验法分析蒸发量的突变点。结果表明，桂北蒸发皿蒸发量年际变化最剧烈（Cv=11．2，Km=1．77），桂南和桂东次之，桂中和桂西年际变化最小。非岩溶发育地区和岩溶发育地区蒸发量的年际变化特征没有差别。20个站点中，10％的蒸发量呈上升趋势，90％的蒸发量呈下降趋势。18个蒸发量下降趋势的站点中，95％信度水平呈显著下降趋势的占72．2％。蒸发量下降主要是由风速降低、云量增加、日较差减小等因素引起。存在突变点且突变趋势显著的站点有10个，占研究总站点数的50．O％。桂中、桂东、桂南3个地区的12个站点都呈下降趋势，这3个地区的蒸发量变化趋势依次是桂南〉桂东〉桂中。岩溶发育地区蒸发量呈下降趋势站点的比例和Z值平均值小于非岩溶发育地区，但其差异不明显。

英文摘要：

Based on the measured data of 20 cm-diameter evaporation pan during 1957--2001 at ZO metrological observation stations in Guangxi Province, the inter-annual change characteristics of pan evaporation are analyzed using the coefficient of variation and extremum ratio. The cumulative filter method, Kendall test method and Mann-Kendall non-parameter statistics test method are used to investigate the change trend of pan evaporation and the change point. The results show that the annual pan evaporation was subject to dramatic change in Northern Guangxi, then that came second in Eastern and Southern Guangxi, and annual pan evaporation showed the minimal change in Central and Western Guangxi. There was no difference between the annual change of pan evaporation in the karst area and no-karst area. The pan evaporation of 10 percent of 20 metrological observation stations showed an increase trend, and 90 percent of that showed a decrease trend, furthermore, the pan evaporation of 72. 2 percent among which displayed an obvious in- crease trend. The decrease of pan evaporation is mainly caused by the wind speed, cloud amount, and diurnal temperature range. Pan evaporation of 50 percent among the studied sites has significant change points. All the pan evaporation of 12 observation sites showed a decrease trend in Central, Eastern and Southern Province, and the change trend of pan evaporation was most obvious in Southern Province. There is no obvious difference between the change trends of pan evaporation in the karst area and no-karst area.