Mirabbasi et al. (2025) Investigating the Dependence Structure of Temperature and Precipitation Concentration with Evapotranspiration in Finland

Identification

• Journal: Water Resources Management
• Year: 2025
• Date: 2025-10-18
• Authors: Rasoul Mirabbasi, Mohammad Nazeri Tahroudi, Alireza Sharifi, Ali Torabi Haghighi
• DOI: 10.1007/s11269-025-04320-5

Research Groups

• Department of Water Engineering, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran
• Department of Water Engineering, Faculty of Agriculture, Lorestan University, Khorramabad, Iran
• Water, Energy and Environmental Engineering Research Unit, Faculty of Technology, University of Oulu, Oulu, Finland

Short Summary

This study performed a first-of-its-kind trivariate analysis using Vine copulas to investigate the dependence structure between temperature concentration (TCI), precipitation concentration (PCI), and potential evapotranspiration (PET) across nine Finnish meteorological stations (1980–2021), revealing significant spatial variations in their joint probabilities and highlighting region-specific flood risks.

Objective

• To investigate the dependence structure and joint probabilistic behavior of temperature concentration (TCI), precipitation concentration (PCI), and potential evapotranspiration (PET) across Finland to understand hydroclimatic shifts and inform water management strategies.

Study Configuration

• Spatial Scale: Nine meteorological stations distributed across Finland (approximately 337,030 km² between 59°–70° N latitude and 19°–31° E longitude).
• Temporal Scale: 42-year period from 1980 to 2021.

Methodology and Data

• Models used: Vine copula modeling (C-vine, R-vine, D-vine), modified Mann–Kendall (MMK) test for trend analysis.
• Data sources: Monthly records of precipitation, temperature, and potential evapotranspiration (PET) from nine Finnish meteorological stations. PET was estimated using the Hargreaves-Samani (HS) method based on daily minimum and maximum air temperatures.

Main Results

• PCI Trends: Seven out of nine stations showed non-significant decreasing trends in annual PCI values (slopes: -0.04 to -0.68 yr⁻¹), indicating a more uniform precipitation distribution. Two stations (HT, KP) showed slight, non-significant increases.
• TCI Trends: Significant increases (p < 0.05) in TCI were observed at HA (+1.50 yr⁻¹), Kl (+1.54 yr⁻¹), SR (+1.30 yr⁻¹), and TK (+1.59 yr⁻¹), indicating increased temperature variability. KP was the only station with a decreasing TCI (−0.06 yr⁻¹).
• PET Trends: All stations exhibited significantly increasing trends (p < 0.05) in PET, with the steepest increases at HA (+69.12 mm/42yr) and KP (+62.86 mm/42yr), signifying increased evaporative demand.
• Trivariate Analysis: Joint probabilities of PCI, TCI, and PET varied significantly across Finland (5–97%). Northern stations (KL, TK) showed stronger linkages (e.g., 97% probability for PCI = 11/TCI = 14/PET = 550 mm/year) compared to southern stations (HT, KK: ≤ 60% probability).
• Flood Risk: PCI values greater than 10 occur with a probability exceeding 50% nationwide, indicating heightened flood risks, which are snowmelt-driven in the north (TCI-sensitive) and rainfall-driven in the south (PCI-sensitive).
• Coupling Strength: The PET-TCI coupling (Kendall's tau, τ = 0.62) was found to be stronger than the PET-PCI relationship (τ = 0.41), suggesting that the PET regime in Finland is primarily temperature-driven.

Contributions

• Presents the first application of Vine copulas for trivariate analysis of temperature concentration (TCI), precipitation concentration (PCI), and potential evapotranspiration (PET) in Finland.
• Provides novel insights into the complex dependence structure of these key hydroclimatic variables in a Nordic region undergoing significant climate change impacts.
• Offers actionable insights for region-specific water management strategies, flood preparedness, drought monitoring, and infrastructure planning under climate change scenarios.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Citation

@article{Mirabbasi2025Investigating,
  author = {Mirabbasi, Rasoul and Tahroudi, Mohammad Nazeri and Sharifi, Alireza and Haghighi, Ali Torabi},
  title = {Investigating the Dependence Structure of Temperature and Precipitation Concentration with Evapotranspiration in Finland},
  journal = {Water Resources Management},
  year = {2025},
  doi = {10.1007/s11269-025-04320-5},
  url = {https://doi.org/10.1007/s11269-025-04320-5}
}