Performance of five surface energy balance models for estimating daily evapotranspiration in high biomass sorghum

2017 ◽  
Vol 128 ◽  
pp. 192-203 ◽  
Author(s):  
Pradeep Wagle ◽  
Nishan Bhattarai ◽  
Prasanna H. Gowda ◽  
Vijaya G. Kakani
2009 ◽  
Vol 13 (7) ◽  
pp. 1061-1074 ◽  
Author(s):  
M. Minacapilli ◽  
C. Agnese ◽  
F. Blanda ◽  
C. Cammalleri ◽  
G. Ciraolo ◽  
...  

Abstract. Actual evapotranspiration from typical Mediterranean crops has been assessed in a Sicilian study area by using surface energy balance (SEB) and soil-water balance models. Both modelling approaches use remotely sensed data to estimate evapotranspiration fluxes in a spatially distributed way. The first approach exploits visible (VIS), near-infrared (NIR) and thermal (TIR) observations to solve the surface energy balance equation whereas the soil-water balance model uses only VIS-NIR data to detect the spatial variability of crop parameters. Considering that the study area is characterized by typical spatially sparse Mediterranean vegetation, i.e. olive, citrus and vineyards, alternating bare soil and canopy, we focused the attention on the main conceptual differences between one-source and two-sources energy balance models. Two different models have been tested: the widely used one-source SEBAL model, where soil and vegetation are considered as the sole source (mostly appropriate in the case of uniform vegetation coverage) and the two-sources TSEB model, where soil and vegetation components of the surface energy balance are treated separately. Actual evapotranspiration estimates by means of the two surface energy balance models have been compared vs. the outputs of the agro-hydrological SWAP model, which was applied in a spatially distributed way to simulate one-dimensional water flow in the soil-plant-atmosphere continuum. Remote sensing data in the VIS and NIR spectral ranges have been used to infer spatially distributed vegetation parameters needed to set up the upper boundary condition of SWAP. Actual evapotranspiration values obtained from the application of the soil water balance model SWAP have been considered as the reference to be used for energy balance models accuracy assessment. Airborne hyperspectral data acquired during a NERC (Natural Environment Research Council, UK) campaign in 2005 have been used. The results of this investigation seem to prove a slightly better agreement between SWAP and TSEB for some fields of the study area. Further investigations are programmed in order to confirm these indications.


2021 ◽  
Vol 15 (9) ◽  
pp. 4465-4482
Author(s):  
Corey Scher ◽  
Nicholas C. Steiner ◽  
Kyle C. McDonald

Abstract. Current observational data on Hindu Kush Himalayas (HKH) glaciers are sparse, and characterizations of seasonal melt dynamics are limited. Time series synthetic aperture radar (SAR) imagery enables detection of reach-scale glacier melt characteristics across continents. We analyze C-band Sentinel-1 A/B SAR time series data, comprised of 32 741 Sentinel-1 A/B SAR images, and determine the duration of seasonal glacier melting for 105 432 mapped glaciers (83 102 km2 glacierized area, defined using optical observations) in the HKH across the calendar years 2017–2019. Melt onset and duration are recorded at 90 m spatial resolution and 12 d temporal repeat. All glacier areas within the HKH exhibit some degree of melt. Melt signals persist for over two-thirds of the year at elevations below 4000 m a.s.l. and for nearly half of the calendar year at elevations exceeding 7000 m a.s.l. Retrievals of seasonal melting span all elevation ranges of glacierized area in the HKH region, extending greater than 1 km above the maximum elevation of an interpolated 0 ∘C summer isotherm and at the top of Mount Everest, where in situ data and surface energy balance models indicate that the Khumbu Glacier is melting at surface air temperatures below −10 ∘C. Sentinel-1 melt retrievals reflect broad-scale trends in glacier mass balance across the region, where the duration of melt retrieved in the Karakoram is on average 16 d less than in the eastern Himalaya sub-region. Furthermore, percolation zones are apparent from meltwater retention indicated by delayed refreeze. Time series SAR datasets are suitable to support operational monitoring of glacier surface melt and the development and assessment of surface energy balance models of melt-driven ablation across the global cryosphere.


2020 ◽  
Vol 15 (01) ◽  
pp. 53-76
Author(s):  
Gabriel Alves Veloso ◽  
Manuel Eduardo Ferreira ◽  
Bernardo Barbosa da Silva

O presente trabalho teve como objetivo a estimativa da evapotranspiração em áreas irrigadas do projeto Jaíba (MG) e áreas circunvizinhas por meio de dados satelitários. Foram utilizadas cinco imagens do satélite Landsat 5 –TM, órbita 219 ponto 70, do ano de 2011. A estimativa da evapotranspiração real diária foi obtida através do algoritmo SEBAL (Surface Energy Balance Algorithm for Land). O SEBAL é constituído de várias etapas, que consiste na estimativa do balanço de radiação e balanço de energia e evapotranspiração. Para a obtenção desses parâmetros, utilizou-se dados da estação meteorológica localizada na cena Landsat. Foram obtidos valores médios para a evapotranspiração no período de 24 horas de 6,85 mm.dia-1, 4,0 mm.dia-1, 2,6 mm.dia-1, 2,2 mm.dia-1 e 3,4 mm.dia-1 para os dias juliano DJ 31, DJ 111, DJ 175, DJ 191 e DJ 255, respectivamente. Observou-se que a evapotranspiração apresentou variação no período analisado devido à quantidade de radiação disponível para cada dia, indicando um comportamento decíduo nas áreas de floresta estacional. A técnica utilizada demonstrou-se eficiente nas análises dos componentes estudados, sendo o SEBAL uma ferramenta importante para a gestão ambiental dos recursos hídricos. Palavras - Chaves: Evapotranspiração; SEBAL; Projeto Jaíba.   DETERMINATION OF REAL EVAPOTRANSPIRATION DAILY IN AREAS OF JAIBA IRRIGATED PROJECT (MINAS GERAIS, BRAZIL) THROUGH IMAGES LANDSAT 5 – TM  Abstract This study aimed to estimate evapotranspiration in irrigated areas of Jaíba project (MG) and surrounding areas through satelitários data. Five images of Landsat 5 -TM were used, orbit 219 point 70, 2011. The estimate of daily evapotranspiration was obtained by SEBAL algorithm (Surface Energy Balance Algorithm for Land) .The SEBAL consists of several stages, consisting in estimating the radiation balance and energy balance and evapotranspiration. To obtain these parameters, we used data from the weather station located on the Landsat scene. Mean values ​​for evapotranspiration were obtained within 24 hours of 6.85 mm.dia-1, 4,0 mm.dia-1, 2,6 mm.dia-1, 2,2-1 and 3 mm.dia , 4 mm.dia-1 for Julian days DJ 31, DJ 111, DJ 175, DJ 191 and DJ 255, respectively. It was observed that the evapotranspiration in growth in the period analyzed due to the amount of radiation available for each day, indicating a behavior in the areas of deciduous seasonal forest. The technique used was efficient in the analysis of the components studied, and the SEBAL an important tool for environmental management of water resources. Keywords: Evapotranspiration; SEBAL; Jaíba project.   DETERMINACIÓN DE LA EVAPOTRANSPIRACIÓN REAL DIARIA EN ÁREAS IRRIGADAS DEL PROYECTO JAÍBA (MINAS GERAIS, BRASIL), MEDIANTE IMAGENES LANDSAT 5 – TM Resumen El presente trabajo tuvo como objetivo la estimativa de evapotranspiración en áreas irrigadas del proyecto Jaíba (MG) y áreas circunvecinas por medio de datos satelitarios. Fueron utilizadas cinco imágenes del satélite Landsat 5 – TM, órbita 219 punto 70, del año 2011. La estimativa de la evapotranspiración real diaria fue obtenida a través del algoritmo SEBAL (Surface Energy Balance AlgorithmforLand). SEBAL es constituido de varias etapas, que consiste en la estimativa del balance de radiación e de energía y evapotranspiración. Para la obtención de esos parámetros, se utilizó datos de la estación meteorológica localizada en la escena Landsat. Fueron obtenidos valores medios para la evapotranspiración en el período de 24 horas de 6,85 mm.dia-1, 4,0 mm.dia-1, 2,6 mm.dia-1, 2,2 mm.dia-1, y 3,4 mm.dia-1 para los días de Juliano DJ 31, DJ 111, DJ 175, DJ 191 y DJ 255, respectivamente. Se observó que la evapotranspiración presentó variación en el período analizado debido a la cantidad de radiación disponible para cada día, indicando un comportamiento caducifolio en las áreas de floresta estacional. La técnica utilizada se mostró eficiente en los análisis de los componentes estudiados, siendo SEBAL una herramienta importante para la gestión ambiental de los recursos hídricos. Palabras - claves: Evapotranspiración; SEBAL; Proyecto Jaíba.


2010 ◽  
Author(s):  
Prasanna H Gowda ◽  
Terry A Howell ◽  
George Paul ◽  
Thomas H Marek ◽  
Paul D Colaizzi

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