Spatiotemporal characteristics of meteorological and hydrological droughts across Europe

Amid ongoing global warming and growing water resource pressures, droughts have intensified in frequency and severity across Europe. Using ERA5 reanalysis data (1970–2024), we assessed four drought indices—meteorological (SPI, SPEI) and hydrological (SRI, RZI)—at 3-, 6-, and 12-month scales. Spatiotemporal dynamics were evaluated through trend analysis (Mann–Kendall), persistence assessment (Hurst exponent), abrupt change detection (mutation test), spatial pattern metrics (Fragstats), and inter-index correlation. Results show that hydrological droughts exhibited stronger trends and persistence than meteorological droughts. Significant intensification emerged in Western, Eastern, and Southern Europe, with SRI and RZI affecting nearly 700 × 10⁴ km². Breakpoints were detected in 1974 for meteorological and 1993–1994 for hydrological indices. Landscape analysis indicated increased patch numbers, higher spatial complexity, and aggregation, particularly for hydrological indices. Inter-index correlations were high at the 12-month scale (|<i>R</i>| &gt; 0.6) but declined (~0.3) at the 3-month scale, revealing divergence between meteorological and hydrological droughts. These findings advance understanding of drought evolution and underlying climate mechanisms, providing scientific support for monitoring, early warning, and adaptive water management strategies in Europe.

在全球变暖持续加剧、水资源压力日益增大的背景下，欧洲各地干旱的发生频率与严重程度均呈上升态势。本研究采用1970–2024年的ERA5再分析数据（ERA5 reanalysis data），针对3个月、6个月及12个月时间尺度下的4类干旱指数——气象干旱指数（SPI, SPEI）与水文干旱指数（SRI, RZI）——开展评估。通过趋势分析（曼-肯德尔检验，Mann–Kendall）、持续性评估（赫斯特指数法，Hurst exponent）、突变检测（突变检验，mutation test）、空间格局指标分析（Fragstats）及指数间相关性分析，对干旱的时空动态特征进行了评价。结果表明，水文干旱的变化趋势与持续性均强于气象干旱。西欧、东欧与南欧的干旱呈现出显著加剧态势，其中SRI与RZI的影响范围近700万平方千米。气象干旱指数的突变点出现在1974年，水文干旱指数的突变时段则为1993–1994年。景观格局分析显示，干旱斑块的数量、空间复杂度与聚集度均有所提升，尤以水文干旱指数对应的特征变化最为明显。指数间相关性在12个月尺度上较高（|R|>0.6），但在3个月尺度上降至约0.3，这揭示了气象干旱与水文干旱之间的分异特征。本研究成果深化了对干旱演变过程及其潜在气候机制的认知，可为欧洲地区的干旱监测、早期预警及适应性水资源管理策略提供科学支撑。