黔西南地区旱涝态势变化规律分析

为探明黔西南地区旱涝态势的变化规律,以黔西南地区望谟县为例,基于标准化降水指数,结合概率统计、趋势拟合、小波分析等方法分析了望谟县1959~2013年的旱涝强度、频率、年代际变化、季节性变化以及周期性变化。结果表明,望谟县发生极端旱涝事件的概率较大,1960s~2010s时间序列内均有水文极端事件发生,尤其是2000年以后,旱涝极端事件的振幅较以往呈现增大趋势,未来几年望谟县可能还会遭受极端干旱事件;旱涝态势年代际变化存在3个主要变化阶段,即1960s~1970s旱涝态势明显转变,1970年以后保持规律的旱涝交替,2000年以后呈现旱涝不平衡的状态,干旱态势占主导;春季和秋季呈现向干旱发展的趋势,夏季和冬季无明显变化;标准化降水指数存在以21~22年为主周期的变化规律。

Change Law of Drought and Flood Situation in Qianxinan Area

Wangmo county is selected as a typical area in Qianxinan state to investigate the temporal patterns of drought and flood during the period of 1959-2013. Temporal patterns including intensity, frequency, inter-annual and seasonal variability, and periodic feature of drought and flood in Wangmo county are investigated by using the standardized precipitation index (SPI) incorporating with probabilistic method, trend analysis and wavelet analysis method. The results indicate that there exists a large probability of appearance of extreme drought and flood; extreme events seem to be occurring frequently from 1960s to 2010s, and the intensity of extremes after 2000 seem to be greater than before; Wangmo county will probably suffer extreme drought in the nearly coming years to a great extent; the inter-annual variability show characteristics of phases: drought and flood events appear a great transformation in the period 1960s-1970s; keeping regular alternate until unbalanced drought and flood appeared after 2000, during which drought dominates; spring and autumn tend to be drought, while summer and winter keep stable; the SPI changes with a primary period of 21-22 a.