Show simple item record

dc.contributor.authorErshadi, Ali
dc.contributor.authorMcCabe, Matthew
dc.contributor.authorEvans, Jason P.
dc.contributor.authorWalker, Jeffrey P.
dc.date.accessioned2015-08-03T11:01:57Z
dc.date.available2015-08-03T11:01:57Z
dc.date.issued2013-04
dc.identifier.issn00344257
dc.identifier.doi10.1016/j.rse.2012.12.007
dc.identifier.urihttp://hdl.handle.net/10754/562697
dc.description.abstractThe influence of spatial resolution on the estimation of land surface heat fluxes from remote sensing is poorly understood. In this study, the effects of aggregation from fine (< 100 m) to medium (approx. 1. km) scales are investigated using high resolution Landsat 5 overpasses. A temporal sequence of satellite imagery and needed meteorological data were collected over an agricultural region, capturing distinct variations in crop stage and phenology. Here, we investigate both the impact of aggregating the input forcing and of aggregating the derived latent heat flux. In the input aggregation scenario, the resolution of the Landsat based radiance data was increased incrementally from 120. m to 960. m, with the land surface temperature calculated at each specific resolution. Reflectance based land surface parameters such as vegetation height and leaf area index were first calculated at the native 30. m Landsat resolution and then aggregated to multiple spatial scales. Using these data and associated meteorological forcing, surface heat fluxes were calculated at each distinct resolution using the Surface Energy Balance System (SEBS) model. Results indicate that aggregation of input forcing using a simple averaging method has limited effect on the land surface temperature and available energy, but can reduce evapotranspiration estimates at the image scale by up to 15%, and at the pixel scale by up to 50%. It was determined that the predominant reason for the latent heat flux reduction in SEBS was a decrease in the aerodynamic resistance at coarser resolutions, which originates from a change in the roughness length parameters of the land surface due to the aggregation. In addition, the magnitude of errors in surface heat flux estimation due to input aggregation was observed to be a function of the heterogeneity of the land surface and evaporative elements. In examining the response of flux aggregation, fine resolution (120. m) heat fluxes were aggregated to coarser resolutions using a range of common spatial interpolation algorithms. Results illustrate that a simple averaging scheme provides the best choice for flux aggregation compared to other approaches such as nearest neighbour, bilinear interpolation or bicubic interpolation, as it not only preserves the spatial distribution of evapotranspiration, but most importantly also conserves the mass balance of evaporated water across pixel and image scales. © 2012 Elsevier Inc.
dc.publisherElsevier BV
dc.subjectAerodynamic resistance
dc.subjectFlux aggregation
dc.subjectInput aggregation
dc.subjectLand surface temperature
dc.subjectLandsat
dc.subjectMODIS
dc.subjectRoughness
dc.subjectSurface Energy Balance System (SEBS)
dc.subjectUncertainty
dc.subjectUpscaling
dc.titleEffects of spatial aggregation on the multi-scale estimation of evapotranspiration
dc.typeArticle
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentEnvironmental Science and Engineering Program
dc.contributor.departmentEarth System Observation and Modelling
dc.identifier.journalRemote Sensing of Environment
dc.contributor.institutionSchool of Civil and Environmental Engineering, The University of NSW, Sydney, Australia
dc.contributor.institutionClimate Change Research Centre, The University of NSW, Sydney, Australia
dc.contributor.institutionDepartment of Civil Engineering, Monash University, Clayton, Australia
kaust.personMcCabe, Matthew


This item appears in the following Collection(s)

Show simple item record