两种干旱指标在干旱致灾因子危险性中的对比分析——以宁夏为例

Comparative Analysis of Two Arid Indexes in Drought Disaster-causing Factors —— A Case Study of Ningxia

致灾因子是灾害风险分析理论体系中的重要组成部分,干旱致灾因子危险性指数由干旱强度和发生概率共同决定。基于致灾因子危险性指数计算模式,对比分析了宁夏中南部山区降水距平百分率和标准化降水指数两种常用干旱指标在致灾因子危险性中的应用。分析结果表明,基于两种干旱指标的宁夏中南部山区干旱致灾因子危险性分布趋势一致,且均与实际相符,考虑到计算的简单易行,可以选择降水距平百分率作为宁夏干旱致灾因子危险性指数分析的依据。从全区干旱灾害风险区划的分析表明,宁夏干旱致灾因子危险性大致呈由南到北逐步增加的趋势。

Drought disastrous factors is an important part of disaster risk analysis theory system,drought hazard risk is determined by drought degree and the probability.Based on the hazard risk computing model,two arid indexes of precipitation anomaly percentage and standard precipitation index are contrasted and analyzed,including the hazard of the drought disaster-causing factors in south mountainous area of Ningxia.The results show that hazard of the drought disaster-causing factors has same trend based on the two arid indexes,which are matched with that of actual conditions.Considering that the method is simple and easy,precipitation anomaly percentage could be chosen as the basis for risk index analysis of the drought disaster-causing factors in Ningxia.Analysis of drought risk zoning of the whole region indicates that the risk of drought increases from south to north in Ningxia.