中文摘要：

从干旱定义与识别、点干旱频率分析和区域干旱频率分析3个方面系统阐述了干旱频率分析研究进展和存在问题，归纳了适用于干旱频率分析的干旱定义，干旱识别存在的主要问题以及区域干旱频率分析研究的3种途径。提出综合利用研究区域水文气象特性、干旱成因、旱情、旱灾，并结合前期的大气环流条件等信息来描述和识别干旱，重点开展对干旱特征变量的理论分布、干旱事件重现期公式和经验频率公式等基本理论的研究，关注区域干旱频率分析，注重对径流、土壤水、地下水和供水系统的干旱特性分析。

英文摘要：

China frequently experiences large scale drought events. The latter have become one ofthe most important restraining factors affecting the socioeconomic development. Drought frequency analysis can reveal the characteristics of drought occurrences and their spatial and temporal distributions. Such an analysis is essential to the water resources planning, designing and management, as well as the risk-based management of drought disasters. In this paper, re- search progresses are systematically reviewed on the definition and identification of droughts and on the point to region- al frequency analysis of droughts. The concerning issues are also reported on. In addition, the drought definitions appli- cable to drought frequency analysis are highlighted. The main problems in drought identifications are discussed. Three approaches for regional frequency analysis of droughts are summarized. Finally, it is proposed that the description and identification of droughts should take full advantages of the regional information on the hydrographical and meteorologi- cal characteristics, the atmospheric circulation condition, as well as the cause and extent of droughts. The basic theo- retical issues in the distribution of variables, the drought return period and the empirical frequency need to be further studied. There should be paid more attention on the analysis of regional drought frequency and drought characteristics related to runoff, soil water and water system.