水文干旱对气象干旱的响应及其临界条件

摘要

The response of hydrological drought to meteorological drought is an important subject for drought research.Taking the Jinjiang River basin which is located in southeastern China as the study area and based on the monthly streamflow and precipitation observed records from 1960 to 2010,the Standardized Precipitation Index (SPI)and Standardized Streamflow Index (SSI)were chosen to represent meteorological drought and hydrological drought,respectively.The run theory was used to identify the main drought events and their characteristics.The relationship between the characteristics of hydrological drought and meteorological drought were established with Logarithm function.Then the response of hydrological droughts to meteorological droughts was discussed and the concept of critical condition that meteorological drought evolved into hydrological drought was proposed.The results indicated that the SPI and SSI indices can effectively reflect the duration and magnitude of drought in Jinjiang River basin.The Logarithm function modeled well the relationship of the hydrological drought response to the meteorologi-cal drought.When the duration of meteorological drought were 1.45 months and magnitude reached 0.8,hydrologi-cal drought happened.The relationship is applicable to early warning of hydrological drought based on meteorologi-cal drought monitoring.%流域水文干旱对气象干旱的响应是干旱研究的重要问题。以东南沿海晋江流域为例，选取1960－2010年逐月实测降水和径流数据，采用标准化降水指数（Standardized Precipitation Index，SPI）和标准化径流指数（Standardized Streamflow Index，SSI）两个干旱指数（分别代表气象干旱和水文干旱）及游程理论对流域主要干旱事件特征进行识别，应用Logarithm函数，建立水文干旱对气象干旱特征的响应关系模型，从而进一步分析了水文干旱对气象干旱的响应关系，并提出了气象干旱演进为水文干旱临界条件的概念。结果表明，多时间尺度的SPI与SSI指数可以有效反映晋江流域气象、水文干旱历时及烈度，用Logarithm函数可以比较好地建立晋江流域水文干旱对气象干旱的响应关系模型，得到气象干旱演进为水文干旱的临界条件为气象干旱历时1.45个月、烈度0.8，该模型的建立也为基于气象干旱监测实现水文干旱预警提供了可能。