基于温度-降水-植被综合干旱指数的长江流域干旱时空动态监测

Spatiotemporal Dynamics Monitoring of Drought in Yangtze River Basin Using Temperature-Precipitation-Vegetation Integrated Dryness Index (TPVDI)

摘要:

随着全球气候变暖加剧，干旱事件日趋严重且频发，精准评估干旱等级，高效监测干旱分布特征及干旱时空演变规律，对及时掌握旱情并制定科学抗旱措施意义重大。以长江流域为研究区，构建了温度-降水-植被综合干旱指数TPVDI（Temperature precipitation vegetation dryness index），通过温度干旱指数（TCI）、降水干旱指数（PCI）和植被干旱指数（VCI）的空间欧氏距离计算得出，并运用变异系数法、Theil-Sen Median趋势分析耦合Mann-Kendall显著性检验方法及Hurst指数法，系统揭示了2001—2019年间长江流域干旱时空动态演变规律。TPVDI在气象干旱、农业干旱和综合干旱监测方面均表现出色，其与SPEI12、TVDI、PA的相关系数分别为-0.4916、0.4299、-0.3985，均通过0.05显著性水平检验，验证了其多维度干旱监测能力，为长江流域干旱评估提供了可靠工具。19年里长江流域整体处于无旱、轻旱灾害状态，重旱区呈现3~5年周期的南北往复迁移特征；整体干旱情况以较低波动变化（34.55%）和中等波动变化（24.22%）为主，干旱变化呈现偏湿趋势；81.43%的区域具有干旱可持续性特征，其中65.18%的区域未来干旱趋势持续减弱，16.25%的区域将面临干旱持续增强风险，主要分布在长江三角洲、湖南及金沙河附近。TPVDI指数突破了单一要素监测的局限性，实现了多源数据协同的干旱动态感知，为流域尺度干旱监测提供了新的方法。

Abstract:

Under intensifying global warming, drought events have become increasingly severe and frequent. Accurate assessment of drought severity, efficient monitoring of drought distribution characteristics, and investigation of spatiotemporal evolution patterns are critical for timely drought management and the formulation of evidence-based mitigation strategies. Focusing on the Yangtze River Basin, the temperature-precipitation-vegetation dryness index (TPVDI), a comprehensive drought index derived from the spatial Euclidean distance integration of the temperature condition index (TCI), precipitation condition index (PCI), and vegetation condition index (VCI) was innovatively developed. The coefficient of variation (CV) method, Theil-Sen Median trend analysis coupled with Mann-Kendall significance testing, and Hurst exponent analysis were systematically applied to reveal the spatiotemporal dynamics of drought from 2001 to 2019. Key findings included that TPVDI demonstrated robust performance in monitoring meteorological, agricultural, and comprehensive droughts, showing significant correlations with SPEI-12, TVDI, and PA (-0.4916, 0.4299, and -0.3985, respectively;all statistically significant at p<0.05). Over the 19-year period, the basin predominantly experienced no drought or mild drought conditions. Severe drought areas exhibited cyclical north-south migration every 3~5 years. Drought variability was dominated by low (34.55%) and moderate fluctuations (24.22%), with an overall wetting trend observed. Persistent drought patterns characterized 81.43% of the basin, with 65.18% of areas projected to experience weakening drought trends, while 16.25% (primarily in the Yangtze River Delta, Hunan Province, and near the Jinsha River) face intensifying drought risks. The TPVDI overcame the limitations of single-factor monitoring, enabling synergistic drought perception through multi-source data integration, and established a novel methodological framework for basin-scale drought monitoring.