Mats et al. (2025) Rainfall Regime Shifts as a Proxy for Hydrological Climate Change Vulnerability

Identification

• Journal: Rocznik Ochrona Środowiska
• Year: 2025
• Date: 2025-12-12
• Authors: Andrii Mats, Olena Mitryasova, Ivan Salamon, Viktor Smyrnov
• DOI: 10.54740/ros.2025.059

Research Groups

• Department of Ecology, Petro Mohyla Black Sea National University, Mykolaiv, Ukraine.
• Department of Ecology, University of Presov, Slovakia.

Short Summary

This study analyzes long-term precipitation shifts in the Mykolaiv region (1980–2024), identifying a 1.7% decadal decline in rainfall and a transition toward more intense, short-duration events. These shifts serve as a proxy for increasing hydrological vulnerability, leading to regional aridification and the shallowness of the Southern Buh River.

Objective

• To quantitatively analyze long-term shifts in the rainfall regime within the Mykolaiv region and determine their direct contribution to escalating hydrological climate change vulnerability.

Study Configuration

• Spatial Scale: Mykolaiv region (Oblast), Ukraine, specifically the Northern Black Sea lowland and the lower reaches of the Southern Buh River basin.
• Temporal Scale: Primary analysis from 1980 to 2024, with long-term trend assessments spanning 1961 to 2024.

Methodology and Data

• Models used: Mathematical modeling using linear regression analysis for trend projection; calculation of the Selyaninov hydrothermal moisture coefficient (GTC) to classify climate aridity.
• Data sources: Regional hydrometeorological service records; National and Regional Reports on the State of the Natural Environment (2023, 2024); Ventusky meteorological time-series database; Google Earth Engine; Ukrainian Hydrometeorological Center.

Main Results

• Precipitation Deficit: Average annual precipitation is critically low, ranging between 409 mm and 469 mm.
• Aridification Trends: A steady downward trend in annual precipitation was identified, decreasing by an average of 1.7% every 10 years ($R^2 = 0.83$).
• Moisture Deficiency: The Selyaninov GTC was calculated at 0.71, categorizing the region as "very dry" to "moderately dry," confirming a clear tendency toward desertification.
• Seasonal Redistribution: Significant shifts were observed compared to the 1961–1990 baseline, with autumn precipitation increasing (October +47%, September +18%) while critical summer/spring months saw sharp declines (August -20%, July -18%, April -17%).
• Event Intensity: An increase in short-duration, high-intensity storm events (averaging 80.6 shower days per year) was recorded, which promotes rapid surface runoff and flash flooding while failing to effectively penetrate soil or recharge aquifers.
• Hydrological Impact: These shifts have led to the shallowness of the Southern Buh River and increased eutrophication risks due to approximately 170 days of high temperatures annually.

Contributions

• The research provides a quantitative framework for using rainfall regime shifts (rather than just total volume) as a reliable proxy for hydrological vulnerability in arid continental regions.
• It documents the specific seasonal "imbalance" in the Northern Black Sea region, highlighting how increased autumn rain does not compensate for the moisture deficit during the primary vegetative and high-evaporation periods.

Funding

• EU Erasmus+ Programme (supporting collaboration between Petro Mohyla Black Sea National University and the University of Presov).

Citation

@article{Mats2025Rainfall,
  author = {Mats, Andrii and Mitryasova, Olena and Salamon, Ivan and Smyrnov, Viktor},
  title = {Rainfall Regime Shifts as a Proxy for Hydrological Climate Change Vulnerability},
  journal = {Rocznik Ochrona Środowiska},
  year = {2025},
  doi = {10.54740/ros.2025.059},
  url = {https://doi.org/10.54740/ros.2025.059}
}

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