贵州近50年来的径流过程时空演变特征及驱动因素诊断

Spatio-Temporal Changes of Runoff Processes and Underlying Driving Forces in Guizhou,Southwestern China (1956～2000)

本文以贵州10个径流站覆盖近50年的实测月径流资料（1956～2000）及19个气象站同期实测资料为基础，结合Mann-Kendall趋势分析和流量历时曲线FDCs等方法，分析了时间变异点（1986年）前后贵州8大主要流域的径流过程的年度和季节变化、洪枯水变化规律及其演变的空间特征。结果表明：（1）从时间规律上看，贵州主要江河近50年间径流变化大部分测站呈现小幅增加趋势，个别下游水文站径流呈明显增加趋势；（2）1987～2000年期间贵州的汛期径流和1956～1986年期间相比更加集中了；（3）贵州大多数水文站月径流洪水指标（Q5）在1986年后有不同幅度增加，而枯水指标（Q95）1986年后涨跌互现。与之对应的洪水指数（Q5／Q50）及枯水指数（Q95／Q50）也存在类似规律；（4）从空间规律上看，贵州西北部地区和东南部地区径流减少，其它地方（主要集中在乌江上游）增加。责州1986年前后近50年时期内的降水及蒸发的空间规律与其径流变化空间规律是基本吻合的，说明贵州过去近50年来的径流过程变化主要是由气候变化引起的。本文的研究结果对保证并促进贵州地区区域水资源、生态与环境和谐健康的可持续发展具有非常重要的战略意义和科学价值。

In this study, spatio-temporal changes in annual precipitation, evaporation, temperature, solar rediation and stream flow in the karst region of Guizhou, southwestern China （1956-2000） were examined using the Mann - Kendall trend analysis, singular-spectrum analysis （SSA）, Lepage test, and flow duration curves （FDCs）. Results indiaeated that： 1） The stream flow during 1956-2000 increased slightly in most catchments; 2） the region of Guizhou experienced significant changes in sea sonal stream flow distribution during the posterior record （1987-2000） compared with those in prior periods （1956-1986）, of which, most catchments showed increasing values of the coefficient of variation for monthly stream flow; 3） the map of stream flow distribution identified reduction of the monthly flow in the northwestern part and increase in the rest parts. The spatial patterns revealed by precipitation and evaporation map are closely associated with those of stream flow, suggesting the impact of climate changes is the prime driving forces dorminating the changes of hydrological processes in Guizhou. The results are beneficial for formulating the regional strategy of water resources management for such a environmentally fragile region.