@Article{OliveiraMorCarBerMat:2018:ImAlEs,
               author = "Oliveira, Bruno Silva and Moraes, Elisabete Caria and 
                         Carrasco-Benavide, Marcos and Bertani, Gabriel and Mataveli, 
                         Guilherme Augusto Verola",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Universidad 
                         Cat{\'o}lica del Maule} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Universidade de S{\~a}o Paulo (USP)}",
                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",
              journal = "Remote Sensing",
                 year = "2018",
               volume = "10",
               number = "8",
                pages = "e1181",
                month = "Aug.",
             keywords = "net radiation, energy balance, eddy covariance data, crop 
                         coefficient, surface albedo.",
             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 (20052007 for USR/PDG sites and 20112015 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.",
                  doi = "10.3390/rs10081181",
                  url = "http://dx.doi.org/10.3390/rs10081181",
                 issn = "2072-4292",
             language = "en",
           targetfile = "oliveira_improved.pdf",
        urlaccessdate = "27 abr. 2024"
}