Chen et al. (2026) Contrary effects of soil moisture-atmosphere feedback on dry and humid heatwaves

Identification

• Journal: Nature Communications
• Year: 2026
• Date: 2026-03-03
• Authors: Sisi Chen, Peng Ji, Shanshui Yuan, Qibo Xu, Yu Ye, Jianyun Zhang
• DOI: 10.1038/s41467-026-70210-y

Research Groups

• The State Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, China
• School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, China
• College of Hydrology and Water Resources, Hohai University, Nanjing, China
• Yangtze Institute for Conservation and Development, Hohai University, Nanjing, China
• California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA

Short Summary

This study investigates the distinct impacts of soil moisture-atmosphere feedback (SAF) on dry and humid heatwaves globally, revealing that SAF amplifies dry heatwaves but has spatially divergent effects on humid heatwaves, reducing their severity in low-to-mid latitudes while intensifying them in high latitudes. These contrary effects are primarily driven by the competition between SAF-induced thermal warming and moisture depletion, which modulate mean wet-bulb temperatures.

Objective

• To determine the role of soil moisture-atmosphere feedback (SAF) in modulating both dry and humid heatwaves.
• To elucidate the differences in the spatial patterns and underlying physical mechanisms of SAF's influence on these two types of heatwaves.

Study Configuration

• Spatial Scale: Global land areas, with specific analysis for low-to-mid latitude regions (e.g., Europe, Australia, North Africa, southwestern North America), high latitude regions (e.g., Alaska, northern Asia, northern Europe), and 26 IPCC SREX regions.
• Temporal Scale: Historical period (1985-2014) relative to a baseline period (1951-1980).

Methodology and Data

• Models used: Coupled Model Intercomparison Project phase 6 (CMIP6) historical experiments (ALL) and Land Feedback Model Intercomparison Project with prescribed Land Conditions (LFMIP-pdLC) experiments. Five CMIP6 models were used: CNRM-CM6-1, EC-Earth3, IPSL-CM6A-LR, MIROC6, and MPI-ESM1-2-LR.
• Data sources: ERA5 reanalysis data for validation and CMIP6 model simulations.

Main Results

• Soil moisture-atmosphere feedback (SAF) substantially reduces the annual total duration and severity of humid heatwaves by 20-40% in low-to-mid latitude regions (e.g., Europe, Australia, North Africa, southwestern North America) with strong soil moisture-atmosphere coupling.
• In contrast, SAF increases the annual total duration and severity of humid heatwaves by ≥50% in northern high-latitude regions (e.g., Alaska, northern Asia, northern Europe).
• SAF generally enhances the duration and severity of dry heatwaves globally, with its impact exceeding 1.5 times the influence of other factors in subtropical regions.
• The spatially divergent effects of SAF on humid heatwaves are primarily attributed to alterations in the mean state of wet-bulb temperature, rather than changes in its variability.
• This mean-state modulation results from a competition between SAF-induced thermal warming and moisture depletion: in low-to-mid latitudes, drying outweighs warming, leading to lower wet-bulb temperatures; in high latitudes, warming dominates, leading to higher wet-bulb temperatures.
• For dry heatwaves, SAF's influence is primarily through shifts in the mean state of dry-bulb temperature, with both mean-state and variability changes contributing to increased heatwave duration and intensity.

Contributions

• Provides the first global-scale assessment of SAF's distinct impacts on humid heatwaves, which are crucial for human health and thermoregulation, extending beyond previous research focused predominantly on dry heatwaves.
• Deepens the mechanistic understanding of SAF's dual regulatory role in extreme heat events by elucidating its influence via temperature-humidity coupling.
• Highlights the necessity for refined, region-specific climate adaptation strategies that account for the latitude-dependent effects of SAF on both humid and dry heatwaves.
• Reveals a previously overlooked climatological cooling effect of SAF on mean wet-bulb temperature in low-latitude and subtropical regions, which suppresses humid heatwave occurrence.

Funding

• National Key Research and Development Program of China (2023YFC3209800)
• National Natural Science Foundation of China (42305175)
• HYMED202405
• The Fundamental Research Funds for the Central Universities (B250201144)
• The Basic Research Project of Jiangsu Province (BK20250090)

Citation

@article{Chen2026Contrary,
  author = {Chen, Sisi and Ji, Peng and Yuan, Shanshui and Xu, Qibo and Ye, Yu and Zhang, Jianyun},
  title = {Contrary effects of soil moisture-atmosphere feedback on dry and humid heatwaves},
  journal = {Nature Communications},
  year = {2026},
  doi = {10.1038/s41467-026-70210-y},
  url = {https://doi.org/10.1038/s41467-026-70210-y}
}