Nikolova et al. (2026) Observed Change in Precipitation and Extreme Precipitation Months in the High Mountain Regions of Bulgaria

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Atmosphere
• Year: 2026
• Date: 2026-01-16
• Authors: Nina Nikolova, Kalina Radeva, Simeon Matev, Martin Gera
• DOI: 10.3390/atmos17010093

Research Groups

[Information not provided in the paper text.]

Short Summary

This study investigates precipitation variability and the occurrence of extreme precipitation months in high mountain regions of Bulgaria (Musala, Botev Peak, Cherni Vrah) from 1937–2024, assessing the influence of large-scale atmospheric circulation patterns. It reveals a significant shift towards drier and more seasonally uneven conditions, with declining wet extremes and increasing dry extremes, linked to specific phases of the North Atlantic Oscillation and Western Mediterranean Oscillation.

Objective

• To provide new information about precipitation variability in high mountain regions of Bulgaria (Musala, Botev Peak, and Cherni Vrah).
• To assess the role of large-scale atmospheric circulation patterns (North Atlantic Oscillation and Western Mediterranean Oscillation) for the occurrence of extreme precipitation months.

Study Configuration

• Spatial Scale: High mountain regions of Bulgaria, specifically Musala, Botev Peak, and Cherni Vrah.
• Temporal Scale: 1937–2024 (88 years). Analysis compared two periods: 1937–1980 and 1981–2024.

Methodology and Data

• Models used: Not applicable; the study primarily uses statistical analysis (percentiles for extreme classification, correlation for atmospheric circulation impact).
• Data sources:
  • Observational precipitation data from Musala, Botev Peak, and Cherni Vrah stations.
  • Indices for the North Atlantic Oscillation (NAO) and Western Mediterranean Oscillation (WeMO).

Main Results

• A statistically significant decrease in winter and spring precipitation was observed at Musala and Cherni Vrah.
• Cherni Vrah exhibited a persistent drying tendency across all seasons.
• The frequency of extremely wet months in winter and autumn has sharply declined since 1981.
• Extremely dry months have become more common since 1981, particularly during the cold season.
• Precipitation erosivity showed station-specific responses: Musala and Cherni Vrah displayed reduced monthly concentration, while Botev Peak retained pronounced warm-season erosive rainfall.
• Circulation analysis indicated that positive North Atlantic Oscillation Index (NAOI) phases favor dry extremes, whereas positive Western Mediterranean Oscillation Index (WeMOI) phases enhance wet extremes.
• Overall, the findings reveal a shift toward drier and more seasonally uneven conditions in Bulgaria’s alpine zone, increasing hydrological risks related to drought, water scarcity, and soil erosion.

Contributions

• Provides novel insights into long-term precipitation variability and extreme events in the high mountain regions of Bulgaria.
• Quantifies the influence of major atmospheric circulation patterns (NAO and WeMO) on the occurrence of extreme precipitation months in the region.
• Identifies a significant shift towards drier and more seasonally uneven precipitation regimes, highlighting increased hydrological risks.
• Offers essential guidance for forecasting hydrological risks and mitigating soil erosion in vulnerable mountain ecosystems, informing adaptive water-resource strategies.

Funding

[Information not provided in the paper text.]

Citation

@article{Nikolova2026Observed,
  author = {Nikolova, Nina and Radeva, Kalina and Matev, Simeon and Gera, Martin},
  title = {Observed Change in Precipitation and Extreme Precipitation Months in the High Mountain Regions of Bulgaria},
  journal = {Atmosphere},
  year = {2026},
  doi = {10.3390/atmos17010093},
  url = {https://doi.org/10.3390/atmos17010093}
}