Biryło (2026) Regime shifts in European basins detected from the water budget and the Combined Climatological Deviation Index

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-08-22
• Authors: Monika Biryło
• DOI: 10.1016/j.jhydrol.2026.136294

Research Groups

• University of Warmia and Mazury in Olsztyn, Poland

Short Summary

The study evaluates hydroclimatic regime shifts in ten major European basins by integrating water budget components and the Combined Climatological Deviation Index (CCDI). It identifies a general hydroclimatic reorganization occurring around 2015, with regional variations in timing and magnitude.

Objective

• To determine if independently derived climatic forcing (CCDI) and total water storage observations (water budget) reveal coherent and consistent hydroclimatic regime shifts at the basin scale.

Study Configuration

• Spatial Scale: Ten major European basins.
• Temporal Scale: Time series analysis (with a specific focus on shifts occurring around 2015).

Methodology and Data

• Models used: Pettitt test (single abrupt change detection), Bai-Perron test (multiple structural shift detection), Mann-Kendall test, and Sen's slope estimator (monotonic trend quantification).
• Data sources: Water budget (WB) series and the Combined Climatological Deviation Index (CCDI).

Main Results

• Evidence of hydroclimatic reorganization was detected across the studied basins, primarily after approximately 2015.
• The timing and magnitude of these regime shifts vary substantially between different European regions.
• The application of combined statistical tests allowed for the clear discrimination between gradual long-term trends and abrupt hydroclimatic regime shifts.

Contributions

• Developed an integrated analytical framework combining the CCDI and water budget components to detect regime shifts.
• Conducted a simultaneous comparative analysis of ten major European basins within a single framework.
• Enhanced the robustness of transition detection by combining the Pettitt and Bai-Perron tests, providing deeper insight into the persistence and physical interpretation of hydroclimatic shifts.

Funding

• Not specified in the provided text.

Citation

@article{Biryło2026Regime,
  author = {Biryło, Monika},
  title = {Regime shifts in European basins detected from the water budget and the Combined Climatological Deviation Index},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136294},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136294}
}