Assessment of global meteorological, hydrological and agricultural drought under future warming based on CMIP6

Quantifying the changes and propagation of drought is of great importance for regional eco-environmental safety and water-related disaster management under global warming. In this study, phase 6 of the Coupled Model Intercomparison Project was employed to examine future meteorological (Standardized Precipitation Index, SPI, and Standardized Precipitation–Evapotranspiration Index, SPEI), hydrological (Standardized Runoff Index, SRI), and agricultural (Standardized Soil moisture Index, SSI) drought under two warming scenarios (SSP2-4.5 and SSP5-8.5). The results show that, across the globe, different types of drought events generally exhibit a larger spatial extent, longer duration, and greater severity from 1901 to 2100, with SPEI drought experiencing the greatest increases. Although SRI and SSI drought are expected to be more intensifying than SPI drought, the models show higher consistency in projections of SPI changes. Regions with robust drying trends include the southwestern United States, Amazon Basin, Mediterranean, southern Africa, southern Asia, and Australia. It is also found that meteorological drought shows a higher correlation with hydrological drought than with agricultural drought, especially in warm and humid regions. Additionally, the maximum correlation between meteorological and hydrological drought tends to be achieved at a short time scale. These findings have important implications for drought monitoring and policy interventions for water resource management under a changing climate. 摘要 在全球变暖背景下, 分析和预测干旱的变化趋势和传播规律对于区域生态环境安全和灾害管理具有重要意义. 本文基于第六次国际耦合模式比较计划 (CMIP6), 分析了SSP2-4.5和SSP5-8.5两种变暖情景下的气象 (标准化降水指数SPI和标准化降水蒸发指数SPEI) , 水文 (标准化径流指数SRI) 和农业 (标准化土壤水分指数SSI) 干旱情况. 从1901年到2100年, 全球范围内不同类型的干旱事件普遍都表现出空间范围, 持续时间和严重程度上的增长, 其中SPEI干旱的增长最为显著. 干旱加剧的地区主要包括美国西南部, 亚马逊地区, 地中海地区, 非洲南部, 亚洲南部和澳大利亚. 尽管结果显示SRI和SSI干旱程度强于SPI干旱, 但不同模式对SPI干旱的预测具有更高的一致性. 此外, 研究发现气象干旱与水文干旱的相关性高于气象干旱与农业干旱的相关性, 在温暖湿润地区尤为明显, 同时水文干旱与短时间尺度的气象干旱具有更好的相关性. 本文的研究结果将有助于气候变化下的干旱监测和水资源管理.