气象干旱诊断评估方法及其在长江中下游地区的应用

干旱是具有一定持续时间和影响范围双重特性的气候异常事件,为客观反映干旱事件的综合影响及演变特征,借鉴“时间-面积”函数的概念,基于综合气象干旱指数建立了气象干旱评估指标和模式,对干旱的时空特征进行了系统的量化表征和可视化表达,并以长江中下游地区为例进行了应用检验。结果表明提出的指标方法能够客观识别和反映出历史典型干旱事件及其强度,对干旱时空分布细节特征的诊断直观具体,对干旱过程起止时间、发展速度、烈度、强度的诊断准确合理。该方法操作简便且物理意义清晰,对省市级、流域及国家级干旱监测评估业务具有良好的应用价值。

METHODS FOR DIAGNOSIS AND ASSESSMENT OF METEOROLOGICAL DROUGHT AND APPLICATION IN THE MIDDLE AND LOWER YANGTZE BASIN

Drought is a climatic anomaly, characterized by certain time constants and spatial extent. In view of the concept of time-area function, comprehensive assessment indices and analysing mode for systematic quantification and visualization of space-time properties of drought are proposed based on the comprehensive monitoring index of meteorological drought (MCI). By application for the middle and lower Yangtze basin, it shows that the assessment indices and procedure proposed above perform well in capturing the magnitude and interannual variation of historical drought, and show a certain capability to determine the start, duration, and strength of a real-time drought process. The assessment indices and procedure are simple in calculation, reasonable in analysis and easy in spread, and thus have a great advantage in the provincial, basin, as well as national drought monitoring and assessment operations.