Evaluation of ECOSTRESS Collection 2 Evapotranspiration Products: Strengths and Uncertainties for Evapotranspiration Modeling

Authors

Zoe Amie Pierrat, California Institute of Technology
Adam J. Purdy, California State University, Monterey Bay
Gregory Halverson, California Institute of Technology
Joshua B. Fisher, Chapman UniversityFollow
Kanishka Mallick, Luxembourg Institute of Science and Technology
Madeleine Pascolini-Campbell, California Institute of Technology
Youngryel Rye, Seoul National University
Martha C. Anderson, U.S. Department of Agriculture
Claire Villanueva-Weeks, California Institute of Technology
Margaret C. Johnson, California Institute of Technology
Brenna Hatch, California Institute of Technology
Evan Davis, California Institute of Technology
Yun Yang, Cornell University
Kerry Cawse-Nicholson, California Institute of Technology

Document Type

Article

Publication Date

6-14-2025

Abstract

The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) collects thermal observations from the International Space Station to support evapotranspiration (ET) research at fine spatial resolutions (70 m × 70 m). Initial ET from ECOSTRESS Collection 1 was used in scientific research and applications, though subsequent analyses identified areas for improvement. This study outlines updates to ECOSTRESS Collection 2 ET and presents an accuracy assessment of ET and auxiliary variables validated against in situ data from AmeriFlux. Key updates in Collection 2 include use of four independent model estimates of instantaneous latent energy (LE) and improved auxiliary forcing data. We find the multi-model ensemble achieves a root mean square error (RMSE) of 106 Wm⁻² for instantaneous observations (reported as LE) and 1.2 mm day⁻¹ for daily retrievals (reported as ET). When considering uncertainty in energy balance closure approaches for site-level data, the RMSE improves to 50 Wm⁻² for instantaneous LE. We observe variable performance based on the solar time of ECOSTRESS acquisition, climate, and vegetation type. Evaluation of auxiliary data highlights limitations in downscaled net radiation and relative humidity, contributing to a diurnal hysteresis in LE. We provide accuracy metrics and model sensitivity to auxiliary data to facilitate user confidence, data adoption, interpretation, and applications. ECOSTRESS is the only instrument capable of providing ET at different times of day at fine spatial scales; thus, this work is an important step toward enhancing the capabilities of satellite-driven ET models in resolving diurnal ET variations and guiding directions for future improvements.

Comments

This article was originally published in Water Resources Research, volume 61, in 2025. https://doi.org/10.1029/2024WR039404

Recommended Citation

Pierrat, Z. A., Purdy, A. J., Halverson, G., Fisher, J. B., Mallick, K., Pascolini‐Campbell, M., et al. (2025). Evaluation of ECOSTRESS Collection 2 evapotranspiration products: Strengths and uncertainties for evapotranspiration modeling. Water Resources Research, 61, e2024WR039404. https://doi.org/10.1029/2024WR039404

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