Sanikhani et al. (2026) Large-scale climate teleconnections and multiscale controls on river water temperature

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-08-24
• Authors: Hadi Sanikhani, Mostafa Khorsandi, Stephen J. Déry, André St‐Hilaire
• DOI: 10.1016/j.jhydrol.2026.136301

Research Groups

• Department of Geography, Earth and Environmental Sciences, University of Northern British Columbia
• Institut national de la recherche scientifique, Centre Eau Terre Environnement (INRS-ETE)

Short Summary

This study investigates the multiscale influence of El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on river water temperature variability in a cold-region Pacific watershed. The results indicate that while seasonal atmospheric forcing dominates the annual thermal cycle, significant non-stationary variability emerges at interannual (2–7 years) and decadal scales.

Objective

• Investigate the multiscale influence of ENSO and PDO on river water temperature variability in a cold-region Pacific watershed.
• Examine how reservoir operations influence the transmission of large-scale climate signals to downstream river thermal regimes.

Study Configuration

• Spatial Scale: The study was conducted at the Nechako Watershed in north-central British Columbia, Canada, which spans approximately 47,200 km2 and covers a transition from sub-boreal plateau to mountainous terrain.
• Temporal Scale: The study analyzed long-term daily water temperature series reconstructed for 1950–2024 using the Air2Stream model.

Methodology and Data

• Models used: Air2Stream model (a hybrid model that represents river temperature dynamics through an air-water energy balance framework)
• Data sources: Observed river water temperature data from the Water Survey of Canada (WSC) and industry partners, including Rio Tinto

Main Results

• The results indicate that while seasonal atmospheric forcing dominates the annual thermal cycle, significant non-stationary variability emerges at interannual (2–7 years) and decadal scales.
• The PDO exhibits persistent and coherent coupling with river water temperature over multi-year to decadal timescales, whereas ENSO influences are episodic and primarily confined to interannual timescales.
• Joint PDO-ENSO interactions are most pronounced at decadal (8–16 year) periods.

Contributions

• This study provides a comprehensive understanding of the multiscale influence of ENSO and PDO on river water temperature variability in a cold-region Pacific watershed.
• The results highlight the importance of accounting for non-stationary climate controls in hydrological thermal assessments.

Funding

• Natural Sciences and Engineering Research Council (NSERC) of Canada
• Social Sciences and Humanities Research Council (SSHRC) of Canada
• University of Northern British Columbia

Citation

@article{Sanikhani2026Largescale,
  author = {Sanikhani, Hadi and Khorsandi, Mostafa and Déry, Stephen J. and St‐Hilaire, André},
  title = {Large-scale climate teleconnections and multiscale controls on river water temperature},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136301},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136301}
}