Bu et al. (2026) NASA’s ECOSTRESS satellite reveals widespread midday depression in ecosystem evapotranspiration

Identification

• Journal: Nature Communications
• Year: 2026
• Date: 2026-08-25
• Authors: Jingyi Bu, Jingfeng Xiao, Yiqi Luo
• DOI: 10.1038/s41467-026-76873-x

Research Groups

• Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA.
• Schmid College of Science and Technology, Chapman University, Orange, CA, USA.
• Hydrosat, Inc., Washington, DC, USA.
• Soil and Crop Sciences Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA.

Short Summary

This study uses evapotranspiration measurements from the ECOSTRESS satellite and machine learning to quantify global midday depression in evapotranspiration. The results show that midday depression primarily occurs during peak-growing seasons in temperate zones and dry periods in the tropics, with a morning shift of the peak evapotranspiration time by > 0.5 h.

Objective

• Investigate the global distribution of midday depression in evapotranspiration using ECOSTRESS satellite data and machine learning.
• Examine how droughts and heatwaves affect diurnal patterns of evapotranspiration.

Study Configuration

• Spatial Scale: Global, with a focus on temperate zones and dry periods in the tropics.
• Temporal Scale: Daily to seasonal, with a focus on peak-growing seasons and drought/heatwave events.

Methodology and Data

• Models used: Random Forest machine learning model trained on ECOSTRESS ET snapshots using continuous ancillary data as predictors.
• Data sources: ECOSTRESS satellite data (2018-2022) and eddy covariance observations.

Main Results

• Widespread morning shift of the peak evapotranspiration time by > 0.5 h in temperate zones and dry periods in the tropics during peak-growing seasons.
• Droughts and heatwaves intensify midday depression, with a peak evapotranspiration time shifting earlier, typically by 0.5 to 1.5 h and approaching 2 h during local extremes.

Contributions

• This study provides an extensive analysis of convergence and variability of diurnal patterns in evapotranspiration among plant functional types (PFTs) and across diverse climatic zones.
• The results highlight the importance of considering midday depression in evapotranspiration when modeling land surface processes and predicting climate change impacts.

Funding

• Not specified.

Citation

@article{Bu2026NASAs,
  author = {Bu, Jingyi and Xiao, Jingfeng and Fisher, Joshua B. and Luo, Yiqi},
  title = {NASA’s ECOSTRESS satellite reveals widespread midday depression in ecosystem evapotranspiration},
  journal = {Nature Communications},
  year = {2026},
  doi = {10.1038/s41467-026-76873-x},
  url = {https://doi.org/10.1038/s41467-026-76873-x}
}