Abidi et al. (2025) Risk-sensitive climate trend detection in the Medjerda High Valley, Tunisia: application of the modified crossing empirical trend analysis (MCETA)

Identification

• Journal: Theoretical and Applied Climatology
• Year: 2025
• Date: 2025-10-27
• Authors: Sahar Abidi, Ahmet Iyad Ceyhunlu, Hamza Pi̇r, Gökmen Çeribaşı, Mahnaz Gümrükçüoğlu Yi̇ği̇t
• DOI: 10.1007/s00704-025-05854-9

Research Groups

• Laboratoire Des Ressources Sylvo-Pastorales, Institut Sylvo-Pastoral de Tabarka, Université de Jendouba, Tunisia
• Faculty of Technology, Department of Civil Engineering, Sakarya University of Applied Sciences, Turkey
• Department of Civil Engineering, Institute of Graduate Education, Sakarya University of Applied Sciences, Turkey
• Department of Environmental Engineering, Sakarya University Engineering Faculty, Sakarya, Turkey

Short Summary

This study applied the Modified Crossing Empirical Trend Analysis (MCETA) to assess temperature and rainfall changes in Tunisia's Medjerda High Valley, revealing a strong warming trend and spatially heterogeneous precipitation patterns with distinct drought and flooding risks at different stations.

Objective

• To identify annual and seasonal temperature and precipitation trends across a range of topographic and climatic gradients in the Medjerda High Valley over 39 years (1985–2023).
• To test the ability of MCETA to systematically evaluate climate trends in comparison with other methods (Sen’s Slope Estimator and CETA), highlighting the benefits of investigating multiple thresholds.
• To explore the use of multiple thresholds (5%, 50%, 95%) to assess climate trends at different levels of risk at a regional scale, allowing the identification of trends not only in the mean but also in extremes.

Study Configuration

• Spatial Scale: Medjerda High Valley, Tunisia (an area of 8,649 km² within the Medjerda River Basin). Data from three meteorological stations: Beja, Jendouba, and Kef.
• Temporal Scale: 39 years (1985–2023), using annual climatic datasets.

Methodology and Data

• Models used: Modified Crossing Empirical Trend Analysis (MCETA), Crossing Empirical Trend Analysis (CETA), Sen’s Slope estimator. Complementary methods included Cumulative Distribution Function (CDF) analysis and the Kolmogorov-Smirnov (K-S) test for data normality and suitability.
• Data sources: Annual rainfall and temperature data obtained from the National Institute of Meteorology (INM) for three meteorological stations (Beja, Jendouba, Kef).

Main Results

• A strong and consistent warming trend was observed across the Medjerda High Valley, with 100% of temperature records demonstrating rising trends.
• Precipitation patterns exhibited significant spatial heterogeneity: 52.4% of rainfall series displayed increasing trends, while 47.6% showed decreasing trends.
• The MCETA method effectively distinguished between median and extreme rainfall behavior, outperforming traditional single-threshold methods by revealing complex, non-linear, and asymmetric trend shapes at 5%, 50%, and 95% risk levels.
• Droughts were more pronounced at the central station (Kef), which showed increasing trends at the median level but decreasing trends at lower and upper extremes, suggesting a shift towards more stable but less varied precipitation.
• Northwestern stations (Jendouba and Beja) maintained a persistent flooding risk, with Jendouba showing rising trends for S₅, S₅₀, and Sen’s slope values, while Beja exhibited increasing trends for low-risk (S₅) and high-risk (S₉₅) slopes despite a decreasing median (S₅₀).

Contributions

• This study represents the first application of the Modified Crossing Empirical Trend Analysis (MCETA) in a North African Mediterranean catchment (Medjerda High Valley).
• It provides a thorough assessment and benchmarking of MCETA against existing approaches (Sen’s Slope and CETA), demonstrating the superior ability of MCETA to analyze climate trends at multiple risk levels (5%, 50%, 95%).
• The research enriches the portfolio of climate trend results at different risk levels within the catchment, offering nuanced information crucial for guiding location-specific adaptation strategies for water resource management and climate resilience.
• It offers improved analytical methods and evidence for water resource managers and climate adaptation planners in Mediterranean and semi-arid regions facing similar climate change issues.

Funding

The authors declare that they have no funding.

Citation

@article{Abidi2025Risksensitive,
  author = {Abidi, Sahar and Ceyhunlu, Ahmet Iyad and Pi̇r, Hamza and Çeribaşı, Gökmen and Yi̇ği̇t, Mahnaz Gümrükçüoğlu},
  title = {Risk-sensitive climate trend detection in the Medjerda High Valley, Tunisia: application of the modified crossing empirical trend analysis (MCETA)},
  journal = {Theoretical and Applied Climatology},
  year = {2025},
  doi = {10.1007/s00704-025-05854-9},
  url = {https://doi.org/10.1007/s00704-025-05854-9}
}