Determining evapotranspiration by using combination equation models with Sentinel-2 data and comparison with thermalbased energy balance in a California irrigated vineyard

Authors: D'URSO, G. - Ariespace Italy; FALANGA, B. - Ariespace Italy; Kustas, William - Bill; Knipper, Kyle; Anderson, Martha; ALSINA, M. - E & J Gallo Winery; HAIN, C. - Nasa Marshall Space Flight Center; Alfieri, Joseph; Prueger, John; Gao, Feng; McKee, Lynn; DE MICHELE, C. - Ariespace Italy; McElrone, Andrew

Submitted to: Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2021
Publication Date: 9/17/2021
Citation: D'Urso, G., Falanga, B., Kustas, W.P., Knipper, K.R., Anderson, M.C., Alsina, M., Hain, C., Alfieri, J.G., Prueger, J.H., Gao, F.N., McKee, L.G., De Michele, C., Mcelrone, A.J. 2021. Determining evapotranspiration by using combination equation models with Sentinel-2 data and comparison with thermalbased energy balance in a California irrigated vineyard. Remote Sensing. 13(18):3720. https://doi.org/10.3390/rs13183720.
DOI: https://doi.org/10.3390/rs13183720

Interpretive Summary: Evapotranspiration is the key variable for determining crop water requirements and it is needed for the optimal allocation of water resources for irrigation. Studies have demonstrated that satellite remote sensing is an effective tool to derive evapotranspiration for supporting irrigation and water resources from local to regional scales. In this paper, an innovative approach for estimating crop evapotranspiration is proposed using a reflectance-based approach with Sentinel-2 satellite data and is compared with tower measurements and an energy balance model using land surface temperature from multiple satellites over irrigated vineyards in the California Central Valley. The results indicate satisfactory agreement of the reflectance-based approach estimates of daily evapotranspiration with the measurements and the model estimates based on land surface temperature under different vine stress conditions. Efforts to integrate these modeling approaches by leveraging information and intermediate output provided by both approaches are planned for improving their utility in computing reliable daily evapotranspiration products.

Technical Abstract: Data acquired during the GRAPEX (Grape Remote-sensing Atmospheric Profile and Evapotranspiration experiment) in California irrigated vineyards have been utilized with Sentinel-2 (S2) data products to derive evapotranspiration (E) and irrigation requirements by implementing the combination equation models of Penman-Monteith and Shuttleworth and Wallace with surface parameters and resistances derived from Sentinel-2 data. Surface parameters derived from Sentinel-2 and used as input in these models are the hemispherical shortwave albedo for computing the net radiation and the leaf area index (LAI); surface resistances are modulated depending on the water status of the soil and canopy water status evaluated by using a spectral index based on the shortwave infrared observation of Sentinel-2. The E products obtained with the combination equation models are evaluated by using eddy covariance flux tower measurements available at a vineyard site in the California Central Valley, and are additionally compared with two thermal-based energy balance models applied to Landsat 7 and 8, namely the DisALEXI (Disaggregated Atmosphere-Land Exchange Inverse, based on the two-source energy balance model TSEB) and a data fusion approach for producing daily maps of E at the resolution of 30 m. The Shuttleworth and Wallace (S-W S-2) model provides accuracy comparable to thermal based methods when using local meteorological data with daily E errors < 1 mm/day, which increased from 1 to 1.5 mm/day using meteorological forcing data from atmospheric models The advantage of using the S-W S-2 modeling approach for monitoring ET is the high temporal revisit time of the Sentinel-2 satellites (3 to 5 days) and the finer pixel resolution (10 m). These results suggest that by integrating thermal-based data fusion approach with S-W S-2 modeling scheme there is potential to increase frequency and reliability of satellite-based daily evapotranspiration products.