东江流域实际蒸发量与蒸发皿蒸发量的对比分析

Comparison of Actual Evapotranspiration and Pan Evaporation

利用东江流域1956-2003年的水文、气象资料,用趋势线分析、集对分析和方差分析方法对年实际蒸发量和年蒸发皿蒸发量的变化特征及其与气象因子的关系进行对比分析,揭示其相同与相异之处。结果表明:实际蒸发量与蒸发皿蒸发量都有减少的趋势,但蒸发皿蒸发量减少的趋势显著,实际蒸发量减少的趋势不显著;两者都在20世纪90年代出现最小值;实际蒸发量与蒸发皿蒸发量存在不确定相关关系和弱的负相关关系。温度与实际蒸发量、蒸发皿蒸发量都为不确定相关关系;风速与蒸发皿蒸发量为正相关,与实际蒸发量为不确定相关关系;随降水量的变化,两种蒸发量的变化相反,即一个增加而另一个减小;随日照时数的变化,趋势线分析与集对分析都反映出两者有相反的变化,通过年景分析,随日照时数的增加,蒸发皿蒸发量增加,实际蒸发量先增加后减小。年日照时数偏多、降水量偏少时,蒸发皿蒸发量显著偏多;年日照时数为中等、降水量偏多时,实际蒸发量最大,但没有达到显著水平。

Based on the climate and hydrological data of Dongiiang River Basin covering the period 1956-2003, the changes of actual evapotranspiration and pan evaporation and their relationship with climatic factors are analyzed to reveal the similarity and dissimilarity. The results show that there is a decreasing trend in both actual evapotranspiration and pan evaporation, with an insignificant decrease in the former while a significant decrease in the latter. Both of the minimum values of evaporation occur in the 1990s. There is an uncertain and weak negative correlation between actual evapotranspiration and pan evaporation. There is an uncertain relationship between air temperature and actual evapotranspiration and pan evaporation. Wind speed presents a positive correlation with pan evaporation, but an uncertain correlation with actual evapotranspiration. The change of rainfall results in the opposite changes with the two kinds of evapotranspiration, if one increases, the other one decreases. Sunlight radiation causes the opposite changes in trendline analysis and set pair analysis. Through climate patterns analysis, pan evaporation increases with radiation, and actual evapotranspiration increases first and then decreases. The pan evaporation is much more significant than the other climate patterns that the sunlight is more than normal, and the precipitation is less than normal. The actual evapotranspiration is much more than other climate patterns in climate patterns that the sunlight is at the medium level, and the precipitation is more than normal.