长江流域20cm蒸发皿蒸发量的时空变化

Spatial-temporal change of 20 cm pan evaporation over the Yangtze River basin

利用长江流域107个气象站1951-2000年的20 cm口径蒸发皿逐日蒸发资料,采用Mann-Kendall趋势检验法和IDW反距离权重空间插值法分析了近50年来,尤其是20世纪90年代长江流域的年和季节蒸发皿蒸发量的时空变化。50年来,长江流域以年平均、夏季和秋季蒸发皿蒸发量显著下降为主要特点,尤以20世纪90年代最为显著,是年平均和夏季蒸发皿蒸发量最小的时期,比前40年平均值分别低-25.9 mm和-36.1 mm,这种趋势中下游地区比上游地区明显得多,尤其是在鄱阳湖流域。

This paper andyzes the trends of 20 cm pan evaporation over the Yangtze River basin from 1951 to 2000 using Mann-Kendall trend test and IDW interpolation methods. The significant negative trends of annual, summer and autumn pan evaporation characterize the trends of pan evaporation since 1951, especially in the 1990s. The annual and summer pan evaporation in the 1990s is the lowest for the recent 50 years ; the annual and summer pan evaporation anomalies in the 1990s are - 25.9 mm and - 36.1 mm, respectively. But this trend is much more significant in the middle and lower reaches than that in the upper reaches in the Yangtze River basin, especially in the Poyanghu basin.