Down-scaling of SEBAL derived evapotranspiration maps from MODIS (250 m) to Landsat (30 m) scales

Hong, Sung-Ho; Hendrickx, Jan M. H.; Borchers, Brian

doi:10.1080/01431161.2010.512929

Cited by 69 publications

(92 citation statements)

References 38 publications

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“…The linear correlation or the difference is then applied to the fine-scale resolution ET data retrieved from Landsat images. Every Landsat pixel is related to the MODIS pixel it falls inside [7,23,57]. This kind of strategy, including both subtraction and regression (slope-intercept and LinZi) schemes, focuses to a greater degree on the differences among coarse pixels and assumes that all of the finer-scale ET pixels within a given coarse pixel (or within a small area for the slope-intercept method) share the same correlation.…”

Section: Discussionmentioning

confidence: 99%

“…This process uses the relationship between ETa data from two MODIS images (or other high temporal resolution datasets) separated by a given time interval [7,23,57]. To advance this type of strategy by building relationships based on Landsat ET over small areas, in this study, spatial patterns from NDVI data within individual fine pixels are highlighted.…”

Section: Methodsmentioning

confidence: 99%

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An NDVI-Based Statistical ET Downscaling Method

Tan

Niu

et al. 2017

Water

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This study proposes a new method for downscaling ETWatch 1-km actual evapotranspiration (ET) products to a spatial resolution of 30 m using Landsat8 normalized difference vegetation index (NDVI) data. The NDVI is employed as an indicator of land-surface vegetation, which displays periodic spatial patterns on the land surface. A 30-m-resolution ten-day ET dataset is then calculated primarily using the NDVI and the historical ratio of coarse NDVI and ET that considers different land cover types. Good agreement and correlations were obtained between the downscaled data and observations from three flux sites in two study areas. The mean bias (MB) per ten-day period ranges from 4.21 mm in Guantao to 1.55 mm in Huazhaizi, and the coefficient of determination (R 2 ) varies from 0.87 to 0.95. The downscaling results show good consistency with the original ETWatch 1-km data over both temporal and spatial scales for different land cover types, with R 2 values ranging from 0.82 to 0.98. In addition, the downscaled results capture the progression of vegetation growth well. This study demonstrates the applicability of the new "de-pixelation" downscaling method in the management of water resources.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

An NDVI-Based Statistical ET Downscaling Method

Tan

Niu

et al. 2017

Water

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“…The ET of 0.3 to one mm day -1 and rainfall less than 10 mm day -1 were calculated for the winter time. This relationship could provide helpful information for cropping irrigation [35], the drought season [50], particularly when we could forecast the ET values [51], and for improved understanding of the interactions between land surfaces and the atmosphere [31,52]. .…”

Section: Figure 6: Line Graph Of Time Series Swat and Beach Et (Calcumentioning

confidence: 99%

Modeling Surface Runoff and Evapotranspiration using SWAT and BEACH for a Tropical Watershed in North Vietnam, Compared to MODIS Products

Nguyễn

Kappas

2015

IJARSG

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Accurate estimation of surface runoff (Q) and evapotranspiration (ET) is a challenging task but an important research topic because both Q and ET play vital roles in the study of the hydrological cycle, of climate change, water resources, flood management and so on. In this paper we will present the modeling method to estimate the daily Q and ET for a medium-sized watershed in the tropical region of the North of Vietnam using the Soil and Water Assessment Tool (SWAT) and Bridging Event and Continuous Hydrological (BEACH) models. The models were calibrated and validated for the river discharge for SWAT and evaporation (E) for BEACH in a 12 year period from 2001 to 2012. The simulated ETs by the models were compared with the satellite-based ET of MODIS products. Our simulation results show that the SWAT and BEACH models are capable of satisfactorily reproducing (with the NSE > 0.62 and R 2 > 0.78) the stream-gauged river discharge and the observed E, respectively. Daily ET varied from 0.3 to 14 mm day -1 and was highest from May to August and lowest from December to March. Although the monthly and yearly MODIS ETs were slightly higher than those of SWAT and BEACH, a strong relationship between them was found with a standard deviation ranging from three to 40 mm. A light decrease of ET values in the 12 years can be seen in the result analyses; however a longer simulation time might be needed to ensure this trend.

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“…The coarse spatial resolution of TIR data from sensors, such as MODIS, necessitated the development of models to disaggregate T Rad [5][6][7][8] and use the disaggregated T Rad for estimating λE with improved spatial resolution. In addition to this, studies have also been carried out to disaggregate evaporative fraction (EF, defined as the ratio of latent heat flux to the sum of sensible and latent heat fluxes) [9] or ET itself [10].…”

Section: Introductionmentioning

confidence: 99%

Spatial Disaggregation of Latent Heat Flux Using Contextual Models over India

et al. 2017

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Estimation of latent heat flux at the agricultural field scale is required for proper water management. The current generation thermal sensors except Landsat-8 provide data on the order of 1000 m. The aim of this study is to test three approaches based on contextual models using only remote sensing datasets for the disaggregation of latent heat flux over India. The first two approaches are, respectively, based on the estimation of the evaporative fraction (EF) and solar radiation ratio at coarser resolution and disaggregating them to yield the latent heat flux at a finer resolution. The third approach is based on disaggregation of the thermal data and estimating a finer resolution latent heat flux. The three approaches were tested using MODIS datasets and the validation was done using the Bowen Ratio energy balance observations at five sites across India. From the validation, it was observed that the first two approaches performed similarly and better than the third approach at all five sites. The third approach, based on the disaggregation of the thermal data, yielded larger errors. In addition to better performance, the second approach based on the disaggregation of solar radiation ratio was simpler and required lesser data processing than the other approaches. In addition, the first two approaches captured the spatial pattern of latent heat flux without introducing any artefacts in the final output.

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Down-scaling of SEBAL derived evapotranspiration maps from MODIS (250 m) to Landsat (30 m) scales

Cited by 69 publications

References 38 publications

An NDVI-Based Statistical ET Downscaling Method

An NDVI-Based Statistical ET Downscaling Method

Modeling Surface Runoff and Evapotranspiration using SWAT and BEACH for a Tropical Watershed in North Vietnam, Compared to MODIS Products

Spatial Disaggregation of Latent Heat Flux Using Contextual Models over India

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