Performance of Sentinel-2 SAFER ET model for daily and seasonal estimation of grapevine water consumption

Authors: SAFRE, ANDERSON - Sao Paulo State University (UNESP); NASSAR, AYMAN - Utah State University; TORRES-RUA, ALFONSO - Utah State University; ABOUTALEBI, MAYHAR - E & J Gallo Winery; SAAD, JOÃO - Sao Paulo State University (UNESP); MANZIONE, RODRIGO - Sao Paulo State University (UNESP); TEIXEIRA, ANTONIO - Embrapa; Prueger, John; McKee, Lynn; Alfieri, Joseph; HIPPS, LAWRENCE - Utah State University; NIETO, HECTOR - University Of Alcala; White, William - Alex; ALSINA, MARIA DEL MAR - E & J Gallo Winery; SANCHEZ, LUIS - E & J Gallo Winery; Kustas, William - Bill; DOKOOZLIAN, NICK - E & J Gallo Winery; Feng, Gary; Anderson, Martha

Submitted to: Irrigation Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2022
Publication Date: 8/18/2022
Citation: Safre, A.L., Nassar, A., Torres-Rua, A., Aboutalebi, M., Saad, J.C., Manzione, R.L., Teixeira, A.H., Prueger, J.H., McKee, L.G., Alfieri, J.G., Hipps, L.E., Nieto, H., White, W.A., Alsina, M., Sanchez, L., Kustas, W.P., Dokoozlian, N., Feng, G.G., Anderson, M.C. 2022. Performance of Sentinel-2 SAFER ET model for daily and seasonal estimation of grapevine water consumption. Irrigation Science. 40:635-654. https://doi.org/10.1007/s00271-022-00810-1.
DOI: https://doi.org/10.1007/s00271-022-00810-1

Interpretive Summary: In water-limited regions, drought has become more common with increasing climate change. Up to 70% of the fresh water used in the United States is for agriculture, so irrigation water for crop production must be managed more efficiently, while maintaining profitable crop yields. Better water management will allow agricultural production to become more environmentally responsible, but it requires accurate estimates of crop water use. A long-term project has focused on water use in vineyards within California's Central Valley, where collection of plant growth observations from hand-held devices, drones, and satellites (remote sensing) has been used at locations to develop and improve models for rapidly estimating water use. This study evaluated an improved model that estimated daily and seasonal water use in California vineyards by using satellite data. Their comparison to local water use measurements indicated that the satellite method provided reliable water use estimates. It also allowed the creation of water use maps showing spatial water patterns within the vineyards from different irrigation rates. The new model will require additional improvements for estimating actual vine water use, but it has shown potential for improving irrigation management by providing maps of actual vine water use of multiple vineyards and for detecting the impact of different irrigation rates on water use efficiency. The results in this study have benefited vineyard managers by reducing irrigation amounts by up to 20%. Additionally, the results have contributed to the expansion of the new water use monitoring methods from vineyards to almond orchards and thus will aid almond producers.

Technical Abstract: Assessment of water consumption is a crucial task for irrigation management in grapevines, especially in areas with limited water resources, which is the case for many vineyards in California Central Valley. This study evaluated the utility of the Simple Algorithm for Evapotranspiration Retrievement (SAFER) to estimate daily and seasonal actual evapotranspiration (ETa) using Sentinel 2 images with 10 m spatial resolution and 5-day revisit time in three vineyards located in Central California. The irrigation systems are monitored with six eddy covariance (EC) flux towers as part of the Grape Remote-sensing Atmospheric Profile and Evapotranspiration eXperiment (GRAPEX). The estimated surface temperature was closely correlated with the observed surface temperature, with R² higher than 0.86 for the analyzed EC towers. After performing an internal calibration, SAFER root-mean-square error (RMSE) values on daily ETa were between 0.62 to 0.84 mm day-1. Daily ETa values tend to be underestimated by the model when there is less water available in the root zone. The highest residuals were found during the months of July and August after stress was induced at a single vineyard. Additionally, the seasonal ET was estimated and compared with the EC observations, showing an average R² ranging from 0.64 to 0.52. Spatial patterns of ETa showed variability differed among the vineyard blocks. The results indicate both limitations and potential utility of SAFER for irrigation management in vineyards using daily or seasonal ETa under different irrigation treatments.