Particular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa

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dc.contributor.authorGibson, L A
dc.contributor.authorMYnch, Z
dc.contributor.authorEngelbrecht, J
dc.date.accessioned2021-10-08T07:04:13Z
dc.date.available2021-10-08T07:04:13Z
dc.date.issued2011
dc.description.abstractThe focus of this paper is on the pre-packaged version of SEBS in ILWIS and the sensitivity of SEBS to some parameters over which the user has some control when using this version of the model, in order to make informed choices to limit uncertainties. The sensitivities of SEBS to input parameters are related to daily ET rather than energy flux results since this is of interest to water managers and other users of the results of the SEBS model. This paper describes some of the uncertainties introduced by the sensitivity of the SEBS model to (a) land surface temperature and air temperature gradient, (b) the choice of fractional vegetation formula, (c) displacement height and the height at which wind speed is measured, and (d) study area heterogeneity. It was shown that SEBS is sensitive to land surface temperature and air temperature gradient and the magnitude of this sensitivity depended on the land cover and whether or not the wet-limit had been reached. The choice of fractional vegetation cover formula was shown to influence the daily ET results by up to 0.7 mm. It was shown that the height of the vegetation canopy should be considered in relation to the weather station reference height to avoid the sensible heat flux from becoming unsolvable due to a negative ln calculation. Finally the study area was shown to be heterogeneous although the resolution at which fluxes were calculated did not significantly impact on energy partitioning results. The differences in the upscaling from evaporative fraction to daily ET at varying resolutions observed implies that the heterogeneity may play the biggest role in the upscaling and the influence of albedo on this calculation should be studied.
dc.identifier.apacitationGibson, L. A., MYnch, Z., & Engelbrecht, J. (2011). Particular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa. <i>Hydrology and Earth System Sciences</i>, 15(1), 295 - 310. http://hdl.handle.net/11427/34456en_ZA
dc.identifier.chicagocitationGibson, L A, Z MYnch, and J Engelbrecht "Particular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa." <i>Hydrology and Earth System Sciences</i> 15, 1. (2011): 295 - 310. http://hdl.handle.net/11427/34456en_ZA
dc.identifier.citationGibson, L.A., MYnch, Z. & Engelbrecht, J. 2011. Particular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa. <i>Hydrology and Earth System Sciences.</i> 15(1):295 - 310. http://hdl.handle.net/11427/34456en_ZA
dc.identifier.issn1027-5606
dc.identifier.issn1607-7938
dc.identifier.ris TY - Journal Article AU - Gibson, L A AU - MYnch, Z AU - Engelbrecht, J AB - The focus of this paper is on the pre-packaged version of SEBS in ILWIS and the sensitivity of SEBS to some parameters over which the user has some control when using this version of the model, in order to make informed choices to limit uncertainties. The sensitivities of SEBS to input parameters are related to daily ET rather than energy flux results since this is of interest to water managers and other users of the results of the SEBS model. This paper describes some of the uncertainties introduced by the sensitivity of the SEBS model to (a) land surface temperature and air temperature gradient, (b) the choice of fractional vegetation formula, (c) displacement height and the height at which wind speed is measured, and (d) study area heterogeneity. It was shown that SEBS is sensitive to land surface temperature and air temperature gradient and the magnitude of this sensitivity depended on the land cover and whether or not the wet-limit had been reached. The choice of fractional vegetation cover formula was shown to influence the daily ET results by up to 0.7 mm. It was shown that the height of the vegetation canopy should be considered in relation to the weather station reference height to avoid the sensible heat flux from becoming unsolvable due to a negative ln calculation. Finally the study area was shown to be heterogeneous although the resolution at which fluxes were calculated did not significantly impact on energy partitioning results. The differences in the upscaling from evaporative fraction to daily ET at varying resolutions observed implies that the heterogeneity may play the biggest role in the upscaling and the influence of albedo on this calculation should be studied. DA - 2011 DB - OpenUCT DP - University of Cape Town IS - 1 J1 - Hydrology and Earth System Sciences LK - https://open.uct.ac.za PY - 2011 SM - 1027-5606 SM - 1607-7938 T1 - Particular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa TI - Particular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa UR - http://hdl.handle.net/11427/34456 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34456
dc.identifier.vancouvercitationGibson LA, MYnch Z, Engelbrecht J. Particular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa. Hydrology and Earth System Sciences. 2011;15(1):295 - 310. http://hdl.handle.net/11427/34456.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Environmental and Geographical Science
dc.publisher.facultyFaculty of Science
dc.sourceHydrology and Earth System Sciences
dc.source.journalissue1
dc.source.journalvolume15
dc.source.pagination295 - 310
dc.source.urihttps://dx.doi.org/10.5194/hess-15-295-2011
dc.subject.otherBurns
dc.subject.otherDisaster Planning
dc.subject.otherHumans
dc.subject.otherMass Casualty Incidents
dc.subject.otherNational Health Programs
dc.subject.otherPractice Guidelines as Topic
dc.subject.otherSocieties, Medical
dc.subject.otherSouth Africa
dc.titleParticular uncertainties encountered in using a pre-packaged SEBS model to derive evapotranspiration in a heterogeneous study area in South Africa
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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