湄公河清盛站水文情势变化分析

以湄公河清盛水文站为例，采用MannKendall统计检验方法和Pettitt突变检验方法分析了1960 ～2003年径流量的变化趋势和突变点，基于水文变化指标，采用变动范围法定量评价了清盛站水文情势 的变化程度。结果表明，清盛站年均流量总体呈下降趋势，枯季平均流量呈上升趋势，汛期平均流量呈 下降趋势；径流系列基本未发生突变；1992年前后出现显著变化的水文指标有河流枯季月均水量、年均 最小流量与出现时间、低流量谷底数与平均持续时间及流量平均变化率与逆转次数；河流水文情势整体 属中度变化。

Analysis of Hydrological Regime Changes of Chiang Saen Station in Mekong River

Based on 1960 2003 daily runoff data of Chiang Saen Station in Mekong River, Mann Kendall statistical test method and Pettitt changepoint test method are used to identify evolution trends and change points of the streamflow. According to indicators of hydrologic alteration(IHA), change degree of hydrological regime of Chiang Saen Station is evaluated quantificationally with range of variability approach(RVA). The results show that the average annual flow appears a downward trend; the monthly flow of dry season appears a upward trend, while the monthly flow of flood season appears a downward trend. The runoff series have no change point basically. Before and after 1992, the obvious change of hydrological regime indexes are average monthly flow in dry season, annual minimum flow and its date, low pulse count and duration, alteration rate and reversal times; the overall change degree of hydrological regime belongs to intermediate level.