Improved albedo estimates implemented in the METRIC model for modeling energy balance fluxes and evapotranspiration over agricultural and natural areas in the Brazilian Cerrado

Silva Oliveira, Bruno; Caria Moraes, Elisabete; Carrasco-Benavides, Marcos; Bertani, Gabriel; Verola Mataveli, Guilherme Augusto

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dc.contributor.author	Silva Oliveira, Bruno
dc.contributor.author	Caria Moraes, Elisabete
dc.contributor.author	Carrasco-Benavides, Marcos
dc.contributor.author	Bertani, Gabriel
dc.contributor.author	Verola Mataveli, Guilherme Augusto
dc.date.accessioned	2018-11-06T12:50:43Z
dc.date.available	2018-11-06T12:50:43Z
dc.date.issued	2018
dc.identifier.uri	http://repositorio.ucm.cl/handle/ucm/1971
dc.description.abstract	In this study we assessed METRIC (Mapping Evapotranspiration at high Resolution with Internalized Calibration) model performance to estimate energy balance fluxes and evapotranspiration (ET) in two heterogeneous landscapes in the Brazilian Cerrado, including fluxes and ET in both agricultural and natural vegetation. The estimates were evaluated by comparing them to flux tower data collected over sugarcane (USR site), woody savanna (PDG site) and stricto-sensu savanna (RECOR site) areas. The selection of the study years (2005–2007 for USR/PDG sites and 2011–2015 for RECOR site) was based on the availability of meteorological data (to be used as inputs in METRIC) and of flux tower data for energy balance fluxes and ET comparisons. The broadband albedo submodel was adjusted in order to improve Net Radiation estimates. For this adjustment, we applied at-surface solar radiation simulations obtained from the SMARTS2 model under different conditions of land elevation, precipitable water content and solar angles. We also tested the equivalence between the measured crop coefficient (Kc_ec) and the reference evapotranspiration fraction (ETrF or F), seeking to extrapolate from instantaneous to daily values of actual evapotranspiration (ETa). Surface albedo was underestimated by 10% at the USR site (showing a better performance for full crop coverage), by 15% at the PDG site (following the woody savanna dynamics pattern through dry and wet seasons) and was overestimated by 21% at the RECOR site. METRIC was effective in simulating the spatial and temporal variability of energy balance fluxes and ET over agricultural and natural vegetation in the Brazilian Cerrado, with errors within those reported in the literature. Net radiation (Rn) presented consistent results (coefficient of determination (R2 ) > 0.94) but it was overestimated by 8% and 9% in sugarcane and woody savanna, respectively. METRIC-derived ET estimates showed an agreement with ground data at USR and PDG sites (R2 > 0.88, root mean square error (RMSE) up to 0.87 mm day−1 ), but at the RECOR site, ET was overestimated by 14% (R2 = 0.96, mean absolute error (MAE) = 0.62 mm.day−1 and RMSE = 0.75 mm day−1 ). Surface energy balance fluxes and ET were marked by seasonality, with direct dependence on available energy, rainfall distribution, soil moisture and other parameters like albedo and NDVI.	es_CL
dc.language.iso	en	es_CL
dc.rights	Atribución-NoComercial-SinDerivadas 3.0 Chile	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/cl/	*
dc.source	Remote Sensing, 10(8), 1181	es_CL
dc.subject	Net radiation	es_CL
dc.subject	Energy balance	es_CL
dc.subject	Eddy covariance data	es_CL
dc.subject	Crop coefficient	es_CL
dc.subject	Surface albedo	es_CL
dc.title	Improved albedo estimates implemented in the METRIC model for modeling energy balance fluxes and evapotranspiration over agricultural and natural areas in the Brazilian Cerrado	es_CL
dc.type	Article	es_CL
dc.ucm.facultad	Facultad de Ciencias Agrarias y Forestales	es_CL
dc.ucm.indexacion	Scopus	es_CL
dc.ucm.indexacion	Isi	es_CL
dc.ucm.doi	doi.org/10.3390/rs10081181	es_CL