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Calibrating satellite-based vegetation indices to estimate evapotranspiration and crop coefficients

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dc.contributor.authorTasumi, Masahiro, author
dc.contributor.authorAllen, Richard G., author
dc.contributor.authorTrezza, Ricardo, author
dc.contributor.authorU.S. Committee on Irrigation and Drainage, publisher
dc.date.accessioned2020-06-01T20:40:33Z
dc.date.available2020-06-01T20:40:33Z
dc.date.issued2006-10
dc.descriptionPresented at Ground water and surface water under stress: competition, interaction, solutions: a USCID water management conference on October 25-28, 2006 in Boise, Idaho.
dc.description.abstractThis paper presents a procedure to estimate actual evapotranspiration (ET) using a satellite-derived vegetation index. Actual ET is computed in a traditional manner using the crop coefficient (Kc) and reference ET (ETref) procedure (i.e., ET = Kc x ETref) with Kc estimated from the satellite-based NDVI. This study calibrated relationships between Kc and NDVI using satellite-based ET determined by surface energy balance. This unique approach enables calibration of the Kc vs NDVI equations using large numbers of sampled fields (in this case, more than 3000). Thus the calibration represents a regional average Kc estimate. The study was conducted for alfalfa, beans, sugar beet, corn, potatoes, and small grain crops, which are the major crops in southern Idaho. Estimation accuracy for ET was statistically evaluated. Average error of seasonal ET was within 5 percent of the energy balance (EB) determined ET for most crop types. Error in seasonal ET from individual fields is expected to be within 10 percent. NDVI based ET was compared with lysimeter measurements of ET from grass and sugar beets. The seasonal error of the NDVI based method was only 2 percent for grass and 6 percent for the sugar beets, as compared to lysimeter measurements. Statistical accuracy assessments suggest that NDVI based ET estimation can be a robust, simple and inexpensive tool to estimate ET from irrigated agricultural crops with reasonable good accuracy.
dc.format.mediumborn digital
dc.format.mediumCD-ROMs
dc.format.mediumproceedings (reports)
dc.identifier.urihttps://hdl.handle.net/10217/207263
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartofIrrigation Management
dc.relation.ispartofGround water and surface water under stress: competition, interaction, solutions, Boise, Idaho, October 25-28, 2006
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.sourceContained in: Ground water and surface water under stress: competition, interaction, solutions, Boise, Idaho, October 25-28, 2006, http://hdl.handle.net/10217/46560
dc.titleCalibrating satellite-based vegetation indices to estimate evapotranspiration and crop coefficients
dc.title.alternativeGround water and surface water under stress
dc.typeText

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