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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) FULL PAPERS : THEME 6- WATER RESOURCES AND HYDROINFORMATICS : EVAPOTRANSPIRATION ESTIMATED IN COLOMBIA USING NDVI DATA AND NEURAL NETWORKS
EVAPOTRANSPIRATION ESTIMATED IN COLOMBIA USING NDVI DATA AND NEURAL NETWORKS
Author : CARLOS JOSÉ GAVIRIA ARBELÁEZ (CJGAVIRIAA@UNAL.EDU.CO), ALEJANDRO GARCÍA RAMÍREZ (ALGARCIARA@UNAL.EDU.CO), NATALIA RUIZ GIRALDO (NARUIZGI@UNAL.EDU.CO), JULIÁN DAVID ROJO HERNÁNDEZ (JDROJOH@GMAIL.COM)
In this work are estimated the fields of real, and monthly evapotranspiration for Colombia from the precipitation reanalysis, NDVI fields extracted from satellite images and average monthly evapotranspiration data extracted from national hydrometeorological network. Artificial intelligence technique known as artificial neural networks for estimating the spatial and temporal evapotranspiration distribution over Colombian territory is used for the period 1981-2000. The methodology consists in the calibration of a neural network with sigmoid functions, which allows the nonlinear interaction between input and output variables. The input variables involved are on one side Normalized Difference Vegetation Index (NDVI) obtained from the Advanced Very High Resolution Radiometer (AVHRR) of the National Oceanic and Atmospheric Administration of the United States (NOAA) with a resolution of 8km; this variable has been shown to have a relatively high correlation with evapotranspiration in agricultural crops and natural ecosystems (r² = 0.81). The correlation between the evapotranspiration from the neural network and the real evapotranspiration from the evaporation tank, converted through Budyko equation, was r = 0.81. An estimate of the monthly evapotranspiration is then obtained for a period of about 19 years, with a spatial resolution of 9.3 km. The results correspond with the expectations,

File Size : 1,301,472 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) FULL PAPERS
Article : THEME 6- WATER RESOURCES AND HYDROINFORMATICS
Date Published : 20/04/2016
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