Hamel et al. (2026) River temperature response to atmospheric heatwaves is modulated by discharge and meltwater

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-02-19
• Authors: Amber van Hamel, Joren Janzing, Manuela I. Brunner
• DOI: 10.1038/s43247-026-03269-6

Research Groups

• WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland
• Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
• Climate Change, Extremes and Natural Hazards in Alpine Regions Research Center CERC, Davos Dorf, Switzerland

Short Summary

This study investigates how river water temperature in Alpine regions responds to atmospheric heatwaves, revealing that only 47% of atmospheric heatwaves lead to riverine heatwaves, with discharge and meltwater anomalies significantly modulating this response.

Objective

• To improve the understanding of how river water temperature responds to atmospheric heatwaves by analyzing the interplay of various hydro-climatic variables that can strengthen or weaken the thermal sensitivity of rivers to such events.

Study Configuration

• Spatial Scale: Alpine rivers, specifically across European Alpine catchments.
• Temporal Scale: Event-based analysis of atmospheric and riverine heatwaves, with implications for future hydro-climatic conditions.

Methodology and Data

• Models used: Not explicitly stated for the core analysis in the abstract; the study appears to rely on observational and statistical analysis, supported by a Python notebook for figure generation.
• Data sources: Hydro-climatic observations (discharge, meltwater, river temperature) from Alpine catchments, provided by the Swiss Federal Office for the Environment and the Austrian Hydrographic Service. Data is available through HydroShare and potentially supplemented by regional reanalysis data (e.g., CERRA) and catchment datasets (e.g., CAMELS-CH, LamaH-CE) referenced in the paper.

Main Results

• Only 47% of atmospheric heatwaves lead to the development of riverine heatwaves.
• Positive anomalies in river discharge and meltwater can prevent the formation of riverine heatwaves.
• Negative anomalies in river discharge strengthen the thermal coupling between atmospheric and river temperatures.
• Future changes in hydro-climatic conditions are projected to increase the sensitivity of Alpine rivers to atmospheric heatwaves.

Contributions

• Provides an improved understanding of the modulating role of hydro-climatic variables (discharge and meltwater) on the thermal sensitivity of rivers to atmospheric heatwaves.
• Quantifies the proportion of atmospheric heatwaves that propagate into riverine heatwaves in Alpine environments.
• Highlights the critical implications of projected future hydro-climatic changes for the thermal vulnerability of Alpine river ecosystems.

Funding

• Not explicitly stated in the provided text.

Citation

@article{Hamel2026River,
  author = {Hamel, Amber van and Janzing, Joren and Brunner, Manuela I.},
  title = {River temperature response to atmospheric heatwaves is modulated by discharge and meltwater},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-03269-6},
  url = {https://doi.org/10.1038/s43247-026-03269-6}
}