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dc.contributor.author
Barraza Bernadas, Verónica Daniela
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Restrepo Coupe, Natalia
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Huete, Alfredo
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Grings, Francisco Matias
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Beringer, Jason
dc.contributor.author
Cleverly, James
dc.contributor.author
Eamus, Derek
dc.date.available
2017-07-11T20:15:26Z
dc.date.issued
2017-01
dc.identifier.citation
Barraza Bernadas, Verónica Daniela; Restrepo Coupe, Natalia; Huete, Alfredo; Grings, Francisco Matias; Beringer, Jason; et al.; Estimation of latent heat flux over savannah vegetation across the North Australian Tropical Transect from multiple sensors and global meteorological data; Elsevier Science; Agricultural And Forest Meteorology; 232; 1-2017; 689-703
dc.identifier.issn
0168-1923
dc.identifier.uri
http://hdl.handle.net/11336/20164
dc.description.abstract
Latent heat flux (LE) and corresponding water loss in non-moisture-limited ecosystems are well correlated to radiation and temperature. By contrast, in savannahs and arid and semi-arid lands LE is mostly driven by available water and the vegetation exerts a strong control over the rate of transpiration. Therefore, LE models that use optical vegetation indices (VIs) to represent the vegetation component (transpiration as a function of surface conductance, Gs) generally overestimate water fluxes in water-limited ecosystems. In this study, we evaluated and compared optical and passive microwave index based retrievals of Gs and LE derived using the Penman-Monteith (PM) formulation over the North Australian Tropical Transect (NATT). The methodology was evaluated at six eddy covariance (EC) sites from the OzFlux network. To parameterize the PM equation for retrievals of LE (PM-Gs), a subset of Gs values was derived from meteorological and EC flux observations and regressed against individual and combined satellite indices, from (1) MODIS AQUA: the Normalized Difference Water Index (NDWI) and the Enhanced Vegetation Index (EVI); and from (2) AMSR-E passive microwave: frequency index (FI), polarization index (PI), vegetation optical depth (VOD) and soil moisture (SM) products. Similarly, we combined optical and passive microwave indices (multi-sensor model) to estimate weekly Gs values, and evaluated their spatial and temporal synergies. The multi-sensor approach explained 40?80% of LE variance at some sites, with root mean square errors (RMSE) lower than 20 W/m2 and demonstrated better performance to other satellite-based estimates of LE. The optical indices represented potential Gs associated with the phenological status of the vegetation (e.g. leaf area index, chlorophyll content) at finer spatial resolution. The microwave indices provided information about water availability and moisture stress (e.g. water content in leaves and shallow soil depths, atmospheric demand) at a high temporal resolution, thereby providing a scaling factor for potential Gs. We applied the newly proposed Gs model to estimate LE at regional scale using global meteorological data. Our derivation could be extended to continental scales providing equally robust estimates of LE in arid and semi-arid biomes. A more accurate estimation of Gs and LE across different savannah classes will improve the analysis of water use efficiency under drought conditions, which is of importance to climate change studies of water, carbon and energy cycling.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier Science
dc.rights
info:eu-repo/semantics/restrictedAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
Latent Heat Flux
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Microwave Indices
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North Australian Tropical Transect
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Optical Indices
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Ozflux
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Surface Conductance
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Otras Ciencias de la Tierra y relacionadas con el Medio Ambiente
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Ciencias de la Tierra y relacionadas con el Medio Ambiente
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CIENCIAS NATURALES Y EXACTAS
dc.title
Estimation of latent heat flux over savannah vegetation across the North Australian Tropical Transect from multiple sensors and global meteorological data
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2017-07-11T13:11:49Z
dc.journal.volume
232
dc.journal.pagination
689-703
dc.journal.pais
Países Bajos
dc.journal.ciudad
Amsterdam
dc.description.fil
Fil: Barraza Bernadas, Verónica Daniela. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
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Fil: Restrepo Coupe, Natalia. University Of Technology Sydney; Australia
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Fil: Huete, Alfredo. University Of Technology Sydney; Australia
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Fil: Grings, Francisco Matias. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
dc.description.fil
Fil: Beringer, Jason. University Of Technology Sydney; Australia. University of Western Australia; Australia
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Fil: Cleverly, James. University Of Technology Sydney; Australia
dc.description.fil
Fil: Eamus, Derek. University Of Technology Sydney; Australia. University of Western Australia; Australia
dc.journal.title
Agricultural And Forest Meteorology
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.agrformet.2016.10.013
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0168192316304051
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