水文干旱与气象干旱临界转变条件的判定及响应关系

水文干旱与气象干旱的响应关系对于建立健全干旱监测预报系统具有重要意义。基于区域水文干旱指数(SHI)与标准化降水指数(SPI),结合游程理论和非线性关系模型分析喀什河流域水文干旱与气象干旱的特征、响应关系及驱动因素。结果表明:水文干旱的年平均干旱历时和干旱烈度大于气象干旱,且随着SPI和SHI时间尺度的增加,识别出的干旱历时和干旱烈度也有所增加。基于三参数(log 3 P1)对数函数(Logarithm)模型可以更好地表征两者的响应关系。在3个月尺度下,气象干旱历时至少为1. 10个月且干旱的烈度至少为0. 83时,将诱发水文干旱;在6个月尺度下,气象干旱历时至少为1. 60个月且干旱的烈度至少为0. 91时,易发生水文干旱。

Judgment of critical transition conditions and the response relationship of hydrological and meteorological droughts

Exploring the response relationship between hydrological and meteorological droughts is of great significance for establishing a sound drought monitoring and forecasting system. Drought characteristics were extracted using a combination of the regional hydrological drought index (SHI) and standardized precipitation index (SPI), then the response relationship and driving factors of hydrological droughts and meteorological droughts in Kashi River Basin were analyzed by nonlinear function model and runs theory. The results indicate that the average annual drought duration and magnitude of hydrological droughts were greater than that of meteorological droughts, and with the increase of SPI and SHI time scale, the identified drought duration and magnitude also increased. The logarithmic function model with three parameters can be used to better characterize the response relationship between hydrological and meteorological droughts. According to this model, when the meteorological drought last no less than 1.10 months and the drought magnitude is no less than 0.83, the hydrological drought will be induced at 3-month scale. When the meteorological drought last no less than 1.60 months and the drought magnitude is no less than 0.91, the hydrological drought will easily occur at 6-month scale.