基于三维视角的长江流域干旱时空演变特征研究

    Spatio-temporal evolution characteristics of drought in Changjiang River Basin based on 3D perspective

    • 摘要: 为克服将时间与空间维度割裂,仅从单一视角分析干旱演变特征的局限性,从三维时空视角出发,基于标准化降水蒸散发SPEI指数,运用三维识别方法,通过建立6个干旱发展演变过程的时空特征变量,系统解析了1960~2022年长江流域干旱时空格局、迁移特征及演变规律。结果表明:1960~2022年长江流域共发生76次干旱,干旱月份占68.0%,夏旱发生频率最高,其次是春旱和秋旱,在1978~2003年间一直呈现出旱涝交替频繁的格局,2003年以后干旱化趋势加剧;长江流域西南地区整体偏旱,青海省、四川省南部、江西省和陕西省等地为旱情高发区;干旱强度与干旱面积均呈增长趋势,干旱历时总体保持稳定,干旱时空迁移速率减缓,时空上整体向东南方向扩散;干旱强度、面积和时空迁移速率的主周期分别为17, 17 a和19 a。提出的三维识别方法与特征变量为干旱监测预警提供了新工具,研究成果可为长江流域干旱防治及水资源优化配置提供参考。

       

      Abstract: In order to overcome the limitation of analyzing drought evolution characteristics from a single perspective with separated temporal and spatial dimensions, this study adopted a 3D spatio-temporal perspective. Based on the Standardized Precipitation Evapotranspiration Index (SPEI), a 3D identification method was applied to systematically analyze the spatio-temporal patterns, migration characteristics, and evolution of droughts in the Yangtze River Basin from 1960 to 2022. Six spatio-temporal characteristic variables of drought development and evolution were established. The results showed that 76 drought events were identified during 1960~2022, with a drought occurrence rate of 68. 0%. Summer droughts occurred most frequently, followed by spring and autumn droughts. A distinct drought-flood alternation pattern persisted from 1978 to 2003, and the trend of drought intensification has increased since 2003. Persistent drought conditions prevailed in the southwestern regions, particularly in Qinghai, southern Sichuan, Jiangxi, and Shaanxi. Both drought intensity and affected area have shown an increasing trend, while drought duration has remained relatively stable. The migration rate of droughts slowed down, with an overall southeastward expansion. The main cycles of drought intensity, affected area, and migration rate were 17 years, 17 years, and 19 years, respectively. The 3D identification method and characteristic variables provide new tools for drought monitoring and early warning systems, offering scientific support for drought prevention and water resource optimization in the Changjiang River Basin.

       

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