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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Publications at this Location » Publication #384196
Research Project: Integrating Remote Sensing, Measurements and Modeling for Multi-Scale Assessment of Water Availability, Use, and Quality in Agroecosystems

Location: Hydrology and Remote Sensing Laboratory

Title: Evaluation of a CONUS-wide ECOSTRESS DisALEXI evapotranspiration product

Author
item CAWSE-NICHOLSON, K. - Jet Propulsion Laboratory
item Anderson, Martha
item YANG, Y. - US Department Of Agriculture (USDA)
item Yang, Yun
item HOOK, S. - Jet Propulsion Laboratory
item FISHER, J. - Jet Propulsion Laboratory
item HALVERSON, G. - Jet Propulsion Laboratory
item HULLEY, G. - Jet Propulsion Laboratory
item HAIN, C. - Nasa Marshall Space Flight Center
item BRUNSELL, N. - University Of Kansas
item DESAI, A. - University Of Wisconsin
item NOVICK, K. - Indiana University

Submitted to: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2021
Publication Date: 9/13/2021
Citation: Cawse-Nicholson, K., Anderson, M.C., Yang, Y., Yang, Y., Hook, S., Fisher, J., Halverson, G., Hulley, G., Hain, C., Brunsell, N., Desai, A.R., Novick, K.A. 2021. Evaluation of a CONUS-wide ECOSTRESS DisALEXI evapotranspiration product. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 14:10117-10133. https://doi.org/10.1109/JSTARS.2021.3111867.
DOI: https://doi.org/10.1109/JSTARS.2021.3111867

Interpretive Summary: The ECOSTRESS thermal imaging sensor was launched to the International Space Station in 2018 with the purpose of providing land surface temperature data for mapping vegetation water use (evapotranspiration, ET) and stress. The USDA disaggregated Atmosphere Land Exchange Inverse disaggregation (DisALEXI) modeling system is one of two models being used to generate ET and evaporative stress products for the mission. This paper investigates the performance of a real-time implementation of DisALEXI running at the NASA Jet Propulsion Laboratory (JPL) in comparison with flux tower measurements of daily ET collected at flux sites across the contiguous United States. The assessment shows that the model performs well for ECOSTRESS imagery collected under clear-sky conditions and at lower view zenith angles. Thorough cloud-clearing of all satellite inputs is essential to the quality of the ET retrieval. With these constraints, the JPL DisALEXI implementation can be used to investigate small-scale ET variability across the United States.

Technical Abstract: The Atmosphere-Land Exchange Inverse disaggregation (DisALEXI) algorithm is a multi-scale energy balance model that estimates evapotranspiration (ET) using land-surface temperature (LST) as a driving remote sensing input. ECOSTRESS is a thermal radiometer mounted on the International Space Station (ISS), and provides near-daily overpass over sites spread throughout the contiguous United States (CONUS). Using LST products from ECOSTRESS, DisALEXI daily (24hr) ET products have been produced over CONUS with 70m resolution and sub-weekly timesteps. This new product was evaluated at 17 CONUS flux sites over a variety of landcover types, yielding accuracies with R2 = 0.8 and RMSE = 0.77 mm/day, which is comparable to previous DisALEXI validation studies. This work extends DisALEXI spatial coverage, and shows that the algorithm is valid over a larger segment of the contiguous United States. This validation also shows the impact of quality flags, as pixels with high view zenith angles or high aerosol optical depth showed greater deviation from field measurements. As a product demonstration, we show a regional map of fine-scale ET, where the fine-scale variation over wider areas can detect small areas of stress much sooner than products with coarse resolution representing average conditions.