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 (|R| > 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.