中文摘要：

利用全国353个气象站1956-2005年的气象资料，系统分析了过去50年间蒸发皿蒸发量、气温及降水的变化趋势，重点对“蒸发悖论”在中国的规律进行分析，并研究了蒸发皿蒸发量与降水的长期变化趋势的关系。研究结果表明：（1）过去50年间，全国范围内气温增加显著、蒸发皿蒸发量呈下降趋势，总体上存在“蒸发悖论”；（2）“蒸发悖论”具有空间上和时间上的不一致，表现在：随着气温增加，东北地区蒸发皿蒸发量呈上升趋势，20世纪80年代中期以后全国范围蒸发皿蒸发量呈上升趋势；（3）过去50年间，降水量变化趋势不明显，降水量与蒸发皿蒸发量变化趋势在空间分布上大体呈逆向关系。

英文摘要：

It is now well established that the surface of Earth has, on average, warmed over the past 50 years. One expected consequence of this warming is that the air near the surface should be drier, which should result in an increase in the rate of evaporation from terrestrial open water bodies. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world over the past 50 years, and it is similar for the reference evapotranspi- ration. The contract between expectation and observation is called the evaporation paradox. Based on the data of 353 weather stations from 1956 to 2005, the trends in pan evaporation, air temperature and precipitation are obtained, and then the evaporation paradox and the relation between precipitation and evaporation are analyzed. The conclusions include： （1） in the past 50 years, the air temperature increased and the pan evaporation decreased, therefore the evaporation paradox actually exist in China; （2） the paradox is not consistent in space or time, for example, the pan evaporation in northeast and after 1980s increased with the increasing of air temperature; and （3） in the past 50 years, the precipitation and the pan evaporation exhibit contrary trend in most areas.