黄河流域气象干旱与水文干旱时空特征及其传递关系

Spatio-temporal characteristics and propagation relationship of meteorological drought and hydrological drought in the Yellow River Basin

基于标准化降水蒸散指数(SPEI)和标准化径流指数(SRI),比较了黄河流域气象干旱和水文干旱的时空分布差异,分析了二者时间尺度上的关联性,并选取典型干旱事件进一步探讨了两种干旱类型的传递关系。结果表明:两种干旱类型空间上有相似的趋势和频次,但在黄河源区和黄河中南部(渭河流域)差异显著,其干旱历时均有随年代延长的趋势,水文干旱历时增长尤为明显;在时间尺度上,SPEI与SRI在大部分区域基本一致,但在黄河源区和渭河流域差异较大,尤其是短时间尺度上差异更显著;气象干旱与水文干旱并非一一对应,多场短历时间断气象干旱受时滞效应、异常气象波动等影响,可能引发一场长历时连续水文干旱或多场短历时间断水文干旱,一场长历时连续气象干旱强度衰减可能引发多场短历时间断水文干旱。

Based on the standardized precipitation evapotranspiration index(SPEI)and standardized runoff index(SRI),the differences between spatio-temporal distributions of meteorological drought and hydrological drought in the Yellow River Basin were compared,and their correlation was analyzed on time scale.Several typical drought events were selected to explore the propagation relationship between the two types of droughts.The results show that the two types of droughts have similar drought trend and frequency in space,but there are significant differences in the source area of the Yellow River and the south-central part of the Yellow River(the Weihe River Basin).The drought duration is prolonged every decade,especially the hydrological drought duration.In terms of time scale correspondence,SPEI and SRI are basically consistent in most regions,while there are significant differences in the source area of the Yellow River and the Weihe River Basin,especially on a short time scale.A meteorological drought does not correspond to a hydrological drought one by one.Affected by time lag effect and abnormal meteorological fluctuation,multiple short-term meteorological droughts may jointly trigger a long-term continuous hydrological drought or multiple short-term hydrological droughts.A long-term continuous meteorological drought may cause multiple short-term hydrological droughts due to intensity attenuation.