NASA’s ECOSTRESS Satellite Reveals Widespread Midday Depression in Ecosystem Evapotranspiration

Authors

• Jingyi Bu, University of New Hampshire
• Jingfeng Xiao, University of New Hampshire
• Joshua B. Fisher, Chapman UniversityFollow
• Yiqi Luo, Cornell University

Document Type

Article

Publication Date

8-25-2026

Abstract

Plants often exhibit a midday depression in water use (i.e., transpiration), reflecting a constraint on their ability to sustain maximum water transport, which may occur at the cost of reduced photosynthesis. Eddy covariance observations and geostationary satellites cannot quantify this widespread phenomenon globally while resolving fine-scale spatial variability. Using evapotranspiration measurements from the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) and machine learning, we quantify the global distribution of midday depression in evapotranspiration. 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. Droughts and heatwaves intensify midday depression, with peak evapotranspiration time shifting earlier, typically by 0.5 to 1.5 h and approaching 2 h during local extremes. By contrast, the coarse resolution upscaled flux products and hourly meteorological reanalysis datasets cannot capture this phenomenon. Midday depression of evapotranspiration detected using ECOSTRESS and machine learning is strongly associated with plant water stress, and helps us better understand how plants use water during drought and heatwaves.

Comments

This article was originally published in Nature Communications, volume 17, in 2026. https://doi.org/10.1038/s41467-026-76873-x

Recommended Citation

Bu, J., Xiao, J., Fisher, J.B. et al. NASA’s ECOSTRESS satellite reveals widespread midday depression in ecosystem evapotranspiration. Nat Commun 17, 8976 (2026). https://doi.org/10.1038/s41467-026-76873-x

Copyright

The authors

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This work is licensed under a Creative Commons Attribution 4.0 License.