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-heat events in middle and upper reaches of 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。基于标准化复合事件指数(SCEI)、标准化干热事件指数(SDHI)、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:① SPI、SCEI、SDHI和BDHI呈不显著增加趋势(Z统计值分别为1.08,0.83,0.46,0.46),而STI呈不显著下降趋势(Z=-0.07),夏季CDHEs、干旱和高温热浪事件变化趋势不显著。② 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0~7.14%。③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CDHEs的概率为16.1%,均呈不显著下降趋势。④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。研究成果可为流域水资源管理和提升区域的抗旱减灾能力提供参考。

       

      Abstract: Compound drought-heat events (CDHEs) are more disastrous than individual events.Therefore, monitoring their spatiotemporal evolution patterns is crucial for guiding disaster prevention and mitigation efforts.In this study, we employed the Standardized Compound Event Index (SCEI), Standardized Drought-Heat Index (SDHI), Blended Drought-Heat Index (BDHI), Standardized Precipitation Index (SPI), and Standardized Temperature Index (STI) to evaluate the spatiotemporal evolution characteristics of CDHEs, droughts, and heatwaves in the middle and upper reaches of the Hanjiang River during the summer season from 1961 to 2022.Furthermore, the monitoring capabilities of SCEI, SDHI, and BDHI in monitoring CDHEs were compared.The results indicated that: ① SPI, SCEI, SDHI, and BDHI displayed insignificant increasing trends (with Z-statistics of 1.08, 0.83, 0.46, and 0.46, respectively), whereas STI exhibited an insignificant decreasing trend (Z=-0.07).Accordingly, the trends in CDHEs, drought, and heatevents were not statistically significant.② The occurrence frequencies of CDHEs and drought events declines with increasing intensity, with the frequency of severe events ranging from 0 to 7.14%.③ The probabilities of occurrence for basin-wide drought events, heatwave events, and CDHEs were 8.1%, 16.1%, and 16.1%, respectively, all displaying insignificant decreasing trends.④ A comprehensive analysis revealed that BDHI outperformed SCEI and SDHI in monitoring CDHEs.These findings can provide references for basin water resources management and enhancing regional drought and disaster mitigation capabilities.

       

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