Chalmers et al. (2026) Evaporative demand delays soil moisture accumulation timing during the dry-to-wet season transition in the Sahel

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Environmental Research Letters
• Year: 2026
• Date: 2026-09-04
• Authors: Christopher Chalmers, Yan Zhang, A. J. Rigden
• DOI: 10.1088/1748-9326/aea2ae

Research Groups

• University of [Name], Department of Earth Sciences
• International Institute for Applied Systems Analysis (IIASA), Ecosystems and Water Resources Program

Short Summary

This study investigates the joint influence of precipitation and atmospheric demand on soil moisture dynamics during the dry-to-wet season transition in the Sahel. The results show that increased evaporative demand can offset increases in precipitation, delaying the emergence of plant-available water.

Objective

• Investigate how precipitation inputs and temperature-driven dry-down jointly influence soil moisture dynamics during the dry-to-wet season transition in the Sahel.

Study Configuration

• Spatial Scale: Semi-arid zone between the Sahara and the humid tropics (approx. 10° N - 20° N latitude)
• Temporal Scale: Daily to decadal scale, with a focus on the period from 2003 to 2024

Methodology and Data

• Models used: Diagnostic soil moisture model incorporating daily maximum temperature as an index of evaporative demand
• Data sources: Satellite-derived precipitation data (e.g., TRMM) and in situ soil moisture measurements

Main Results

• Soil moisture onset is systematically delayed relative to precipitation onset across much of the Sahel.
• Trends in soil moisture onset and precipitation onset diverge in an east–west pattern.
• Including daily maximum temperature alongside precipitation in the diagnostic model substantially improves its ability to reproduce onset timing.

Contributions

• This study highlights the importance of atmospheric demand alongside precipitation inputs when assessing shifts in soil water availability across the Sahel, with potential implications for rainfed agricultural systems.

Funding

• This research was supported by the European Research Council (ERC) under grant agreement no. [Number], and the International Institute for Applied Systems Analysis (IIASA) through its Ecosystems and Water Resources Program.

Citation

@article{Chalmers2026Evaporative,
  author = {Chalmers, Christopher and Zhang, Yan and Rigden, A. J.},
  title = {Evaporative demand delays soil moisture accumulation timing during the dry-to-wet season transition in the Sahel},
  journal = {Environmental Research Letters},
  year = {2026},
  doi = {10.1088/1748-9326/aea2ae},
  url = {https://doi.org/10.1088/1748-9326/aea2ae}
}