近50年岷江上游潜在蒸散量的时空变化特征

Spatio-temporal variation of potential evapotranspiration in upper Min River Basin during 1961-2010

潜在蒸散量的变化对水分循环与能量平衡均具有重要的意义。文中利用1961-2010年岷江上游及周边20个气象站的逐日气象资料,采用地形矫正的Hargreaves模型计算了潜在蒸散量,并结合小波分析和M-K突变检测方法分析了其时间序列变化特征。结果表明:岷江上游潜在蒸散量呈现由西北向东南逐渐上升的趋势;年潜在蒸散量以12a为准周期变化,潜在蒸散量呈现出波动中上升的趋势,尤其是90年代以来,上升趋势更为明显;而区域内年降水量呈现明显的下降趋势。岷江上游暖干化趋势明显,尤其是近20年,暖干化趋势加剧,生态环境受到严重威胁。

The change of potential evapotranspiration has important significance for water cycle and energy balance. In this researchthe daily climatic data of 20 weather stations on the upper Min River Basin and peripheral areas from 1961 to 2000 were used to calculate potential evapotranspiration by using Hargreaves model which was corrected based on the terrain and climate conditions of Sichuan. The characteristics of time series range of PE was analyzed by Mexican Hat Wavelet and Mann-Kendall abrupt change test. The results showed that： it had upward trend from northwest to the southeast in the upper Min River Basin; the annual potential evapotranspiration was quasi-periodic oscillations of 12 years; it had an obvious upward trend since the 90＇s. The upper Min River Basin had distinct warming and drying trend,especially in the recent 20 years,the worse trend of arid and warm was serious threat to the ecological environmental safety.