Hamel (2026) River temperature response to atmospheric heatwaves in the European Alps

Identification

• Journal: Open MIND
• Year: 2026
• Date: 2026-02-04
• Authors: Amber van Hamel
• DOI: 10.4211/hs.2d0006fde39d411eb80093991eab85ba

Research Groups

• Swiss Federal Institute of Technology, Zurich (ETH Zurich)
• WSL Institute for Snow and Avalanche Research SLF, Davos
• Climate Change, Extremes and Natural Hazards in Alpine Regions Research Center CERC, Davos GR, CH

Short Summary

This study investigates how river temperature responds to atmospheric heatwaves across 275 catchments in the European Alps, finding that the response is significantly modulated by river discharge and meltwater contributions.

Objective

• To analyze the response of river temperature to atmospheric heatwaves in the European Alps.
• To determine how this river temperature response is modulated by factors such as discharge and meltwater.

Study Configuration

• Spatial Scale: 275 river gauging stations and their catchments across Switzerland and Austria (European Alps). Catchment areas range up to several hundreds of square kilometers (km²), and elevations are provided in meters above sea level (m.a.s.l.). Geographic coverage spans from 45.7333° N to 48.9768° N latitude and 5.7019° E to 17.3254° E longitude.
• Temporal Scale: A 10-year period from 2011 to 2021. Annual regimes are constructed based on the 50th percentile of mean daily values, smoothed over a 30-day window. Heatwave events and variable z-scores are analyzed over 5-day periods.

Methodology and Data

• Models used: Not explicitly stated that models were used to generate the primary data. The study primarily uses observed and derived hydro-climatic variables.
• Data sources:
  • Data from 275 river gauging stations in Switzerland and Austria.
  • Catchment delineations and characteristics, including area (km²), mean/median/range elevation (m.a.s.l.), fraction of precipitation as snow (dimensionless), glacier fraction (dimensionless), mean daily specific discharge (mm d⁻¹), and hydrologic regime.
  • Annual regimes (2011-2021) for 11 hydro-climatic variables: air temperature (°C), water temperature (°C), discharge (mm d⁻¹), surface net solar radiation (J m⁻²), relative humidity (%), precipitation (mm d⁻¹), actual evaporation (mm d⁻¹), precipitation minus actual evaporation (mm d⁻¹), liquid volumetric soil moisture (m³ m⁻³), meltwater (snowmelt + glacial melt, mm d⁻¹), and meltfraction (dimensionless).
  • Detailed information on identified atmospheric and riverine heatwaves per catchment, including their duration (days), overlap, and time lag (days).
  • Absolute values, anomalies, and 5-day mean z-scores for the 11 variables during atmospheric heatwaves.
  • Timeseries (2011-2021) of 5-day z-scores for air temperature, water temperature, meltwater, and discharge.

Main Results

• The study found that the response of river temperature to atmospheric heatwaves in the European Alps is significantly modulated by river discharge and meltwater.
• A comprehensive dataset was compiled, detailing hydro-climatic conditions and heatwave characteristics across 275 catchments, providing the empirical basis for this finding.
• The dataset includes annual regimes and heatwave-specific metrics (absolute values, anomalies, z-scores) for 11 key variables, enabling detailed analysis of the modulating factors.

Contributions

• Provides a unique and extensive dataset for 275 river catchments in the European Alps, covering a 10-year period (2011-2021), specifically tailored for studying river temperature responses to heatwaves.
• Offers crucial insights into the modulating role of discharge and meltwater on river temperature during atmospheric heatwaves, which is vital for understanding climate change impacts on alpine river ecosystems.
• Facilitates future research and validation studies on hydro-thermal responses in complex mountain environments by providing processed data, including annual regimes, heatwave events, and z-scores for multiple hydro-climatic variables.

Funding

The specific funding for the research paper "River temperature response to atmospheric heatwaves is modulated by discharge and meltwater" is not explicitly detailed in the provided dataset description. The National Science Foundation (NSF) awards (1148453, 1148090, 1664018, 1664061, 1338606, 1664119, and 1849458) are acknowledged as supporting the HydroShare platform itself, not necessarily the specific research presented.

Citation

@article{Hamel2026River,
  author = {Hamel, Amber van},
  title = {River temperature response to atmospheric heatwaves in the European Alps},
  journal = {Open MIND},
  year = {2026},
  doi = {10.4211/hs.2d0006fde39d411eb80093991eab85ba},
  url = {https://doi.org/10.4211/hs.2d0006fde39d411eb80093991eab85ba}
}