汉江中上游夏季高温干旱复合事件时空演变规律

    Spatiotemporal evolution patterns of compound drought and heat events in the Upper and Middle of the Hanjiang River

    • 摘要: 高温干旱复合事件(CDHEs)相较于单一事件的致灾性更强,监测其时空演变规律对指导防灾减灾工作至关重要。本文基于标准化复合事件指数(SCEI)、标准化干热事件指数(SDHI)和混合干热事件指数(BDHI)、标准化降水指数(SPI)和标准化温度指数(STI)对汉江中上游流域(MUHJB)1961-2022年夏季CDHEs、干旱和高温热浪事件的时空演变特征进行评估,并比较SCEI、SDHI和BDHI对CDHEs的监测能力。结果表明:SPI、SCEI、SDHI和BDHI呈不显著增加趋势(Z_SCEI=0.83,Z_SDHI=0.46,Z_BDHI=0.46,Z_SPI=1.08),而STI呈不显著下降趋势(Z_STI=-0.07),夏季复合高温干旱、干旱和高温事件变化趋势不显著。CDHEs和干旱事件的发生频率随等级的增加而递减,其中重度事件的发生频率介于0至7.14%之间。发生全域性干旱事件的概率为8.1%,全域性高温热浪事件的概率为16.1%,全域性高温干旱复合事件的概率为16.1%,均呈不显著下降趋势。综合分析得出BDHI在监测CDHEs方面相较于SCEI和SDHI表现更为优越。研究结果可以为流域水资源管理和提升区域的防旱减灾能力提供参考。

       

      Abstract: The disaster effects resulting from the compound drought and heat events (CDHEs) are significantly stronger than those caused by single events. Therefore, monitoring their spatiotemporal evolution patterns is crucial for guiding disaster prevention and mitigation efforts. In this study, we evaluate spatiotemporal evolution characteristics of CDHEs、droughts and heatwave events during the summer season (1961-2022) in the Middle and Upper Hanjiang Basin (MUHJB) using the Standardized Compound Event Index (SCEI), the Standardized Drought-Heat Index (SDHI), and the Blended Drought-Heat Index (BDHI), along with the Standardized Precipitation Index (SPI) and the Standardized Temperature Index (STI). Furthermore, the monitoring capabilities of SCEI, SDHI, and BDHI for CDHEs are compared. The results indicate that SPI, SCEI, SDHI, and BDHI displayed non-significant increasing trends (Z_SCEI=0.83,Z_SDHI=0.46,Z_BDHI=0.46,Z_SPI=1.08). In contrast, STI exhibited a non-significant decreasing trend (Z_STI=-0.07). Accordingly, the trends in CDHEs, drought, and heat events were statistically insignificant. The occurrence frequency of CDHEs and drought events declines with increasing severity level, specifically, the frequency of severe events varied between 0 and 7.14%. The probabilities were 8.1% for region-wide drought events, 16.1% for region-wide heatwaves, and 16.1% for region-wide CDHEs. All these probabilities exhibited statistically insignificant decreasing trends. The integrated assessment indicates that BDHI provides superior performance compared to SCEI and SDHI for the monitoring of CDHEs. The research findings can offer valuable insights for guiding watershed water resources management and enhancing regional drought resilience and disaster mitigation capacity.

       

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