scholarly journals Spatial Variability of Daily Evapotranspiration in a Mountainous Watershed by Coupling Surface Energy Balance and Solar Radiation Model with Gridded Weather Dataset

Proceedings ◽  
2018 ◽  
Vol 2 (7) ◽  
pp. 342
Author(s):  
Ricardo Neves de Souza Lima ◽  
Celso Bandeira de Melo Ribeiro
Keyword(s):  
Energy Balance ◽  
Solar Radiation ◽  
Surface Energy ◽  
Spatial Variability ◽  
Surface Energy Balance ◽  
Radiation Model ◽  
Mountainous Watershed ◽  
Daily Evapotranspiration ◽  
Solar Radiation Model

scholarly journals Impacts of topographic shading on direct solar radiation for valley glaciers in complex topography

2019 ◽  
Vol 13 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Matthew Olson ◽  
Summer Rupper
Keyword(s):  
Energy Balance ◽  
Solar Radiation ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Direct Solar Radiation ◽  
High Mountain ◽  
Clear Sky ◽  
Glacier Ice ◽  
Solar Radiation Model ◽  
North And South

Abstract. Topographic shading, including both shaded relief and cast shadowing, plays a fundamental role in determining direct solar radiation on glacier ice. However, shading has been oversimplified or incorrectly incorporated in surface energy balance models in some past studies. In addition, no systematic studies have been conducted to evaluate relationships between shading and other topographic characteristics. Here we develop a topographic solar radiation model to examine the variability in irradiance throughout the glacier melt season due to topographic shading and combined slope and aspect. We apply the model to multiple glaciers in high-mountain Asia (HMA) and test the sensitivity of shading to valley aspect and latitude. Our results show that topographic shading significantly alters the potential direct clear-sky solar radiation received at the surface for valley glaciers in HMA, particularly for north- and south-facing glaciers. Additionally, we find that shading can be extremely impactful in the ablation zone. Cast shadowing is the dominant mechanism in determining total shading for valley glaciers in parts of HMA, especially at lower elevations. Although shading can be predictable, it is overall extremely variable between glacial valleys. Our results suggest that topographic shading not only is an important factor contributing to surface energy balance but could also influence glacier response and mass balance estimates throughout HMA.

scholarly journals Impacts of topographic shading on direct solar radiation for valley glaciers in complex topography

2018 ◽  
Author(s):  
Matthew H. Olson ◽  
Summer B. Rupper
Keyword(s):  
Energy Balance ◽  
Solar Radiation ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Direct Solar Radiation ◽  
High Mountain ◽  
Clear Sky ◽  
Glacier Ice ◽  
North And South ◽  
Predictable Characteristics

Abstract. Topographic shading, including both shaded relief and cast shadowing, plays a fundamental role in determining direct solar radiation on glacier ice. However, this parameter has been oversimplified or incorrectly incorporated in surface energy balance models in some past studies. Here we develop a topographic solar radiation model to examine the variability in irradiance throughout the glacier melt season due to topographic shading and combined slope and aspect. We apply the model to multiple glaciers in High Mountain Asia (HMA), and test the sensitivity of shading to valley-aspect and latitude. Our results show that topographic shading significantly alters the potential direct clear-sky solar radiation received at the surface for valley glaciers in HMA, particularly for north- and south-facing glaciers. Additionally, we find that shading can be extremely impactful in the ablation zone. Cast shadowing is the dominant mechanism in determining total shading for valley glaciers in parts of HMA, especially at lower elevations. Although shading has some predictable characteristics, it is overall extremely variable between glacial valleys. Our results suggest that topographic shading is not only an important factor contributing to surface energy balance, but could also influence glacier response and mass balance estimates throughout HMA.

scholarly journals DETERMINAÇÃO DA EVAPOTRANSPIRAÇÃO REAL DIÁRIA EM ÁREAS IRRIGADAS DO PROJETO JAÍBA (MINAS GERAIS, BRASIL), MEDIANTE IMAGENS LANDSAT 5 - TM

2020 ◽  
Vol 15 (01) ◽  
pp. 53-76
Author(s):  
Gabriel Alves Veloso ◽  
Manuel Eduardo Ferreira ◽  
Bernardo Barbosa da Silva
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Minas Gerais ◽  
Radiation Balance ◽  
Mean Values ◽  
Daily Evapotranspiration ◽  
Landsat 5 Tm ◽  
Surrounding Areas

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.

scholarly journals Estimativa do Saldo de Radiação Instantâneo na Cidade do Recife, através de Imagens do Satélite LANDSAT 5 TM (Estimation of Instantaneous Radiation Balance in City of Recife, Via Satellite Images LANDSAT 5 TM)

2011 ◽  
Vol 4 (3) ◽  
pp. 589 ◽  
Author(s):  
Elvis Bergue Mariz Moreira ◽  
Ranyére Silva Nóbrega ◽  
Bernardo Barbosa da Silva
Keyword(s):  
Energy Balance ◽  
Solar Radiation ◽  
Surface Energy ◽  
Urban Areas ◽  
Satellite Images ◽  
Surface Energy Balance ◽  
Radiation Balance ◽  
Abstract Knowledge ◽  
Landsat 5 Tm ◽  
The City

O conhecimento do saldo de radiacao em areas urbanas e fundamental em estudos de monitoramento de mudanças climaticas e pode ser um indicador de urbanizacao vivenciando por uma determinada area, contudo apresenta-se no campo das pesquisas cientificas pouco exploradas. O principal objetivo desse trabalho foi a obtencao do saldo de radiacao instantaneo na cidade do Recife. Para tanto, foram utilizadas duas imagens do Mapeador Tematico do satélite Landsat 5 referente as datas 26 de agosto de 2006 e 06 de setembro 2010 na orbita e ponto 215/66. As imagens foram processadas atraves do algoritmo SEBAL (Surface Energy Balance Algorithm for Land) que e baseado na irradiacao medida nos canais reflectivos (1,2,3,4,5 e 6). Os resultados encontrados apontaram para as imagens em estudo, os menores valores do (Rn) nas areas urbanas e os maiores foram encontrados nas areas com vegetacao e corpos hidricos. A cena referente ao ano de 2006 apresentou na area urbana valores de (Rn) inferiores a 692 Wm-2 , enquanto o ano de 2010 apresentou 730 Wm-2. De modo geral, os maiores valores de (Rn) foram encontrados na imagem de 2010, tal aumento pode esta associado a saxonalidade da radiacao solar. Palavras chaves: radiacao solar, sensoriamento remoto, algoritmo sebal  Estimation of Instantaneous Radiation Balance in City of Recife, Via Satellite Images LANDSAT 5 TM    ABSTRACT  Knowledge of the radiation balance in urban areas is essential in monitoring studies of climate change and can be an indicator of urban living for a certain area, but has in the field of scientific research unexplored. The main objective of this work was to obtain the instantaneous net radiation in the city of Recife. Therefore, we used two images from Landsat Thematic Mapper 5 for the dates August 26, 2006 and September 6, 2010 point in the orbit and 215/66. The images were processed through the algorithm SEBAL (Surface Energy Balance Algorithm for Land) which is based on irradiation as reflective channels (1,2,3,4,5 and 6). The results pointed to the images under study, the lowest values of (Rn) in urban areas and the largest were found in areas with vegetation and water bodies. The scene for the year 2006 presented in the urban area values (Rn) of less than 692 Wm-2, while the year 2010 showed 730 Wm-2. In general, the highest values of (Rn) were found in the image of 2010, this increase is associated with can saxonalidade solar radiation.  Keywords: solar radiation, remote sensing, algorithm sebal

Surface Energy Balance System for Estimating Daily Evapotranspiration Rates in the Texas High Plains

2010 ◽  
Author(s):  
Prasanna H Gowda ◽  
Terry A Howell ◽  
George Paul ◽  
Thomas H Marek ◽  
Paul D Colaizzi
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
High Plains ◽  
Balance System ◽  
Texas High Plains ◽  
Daily Evapotranspiration

scholarly journals A simple explanation for the sensitivity of the hydrologic cycle to global climate change

2013 ◽  
Vol 4 (2) ◽  
pp. 853-868 ◽  
Author(s):  
A. Kleidon ◽  
M. Renner
Keyword(s):  
Energy Balance ◽  
Solar Radiation ◽  
Surface Energy ◽  
Surface Temperature ◽  
Greenhouse Effect ◽  
Surface Energy Balance ◽  
Hydrologic Cycle ◽  
Maximum Power ◽  
Solar Radiation Management ◽  
Simple Explanation

Abstract. The global hydrologic cycle is likely to increase its strength with global warming. Climate models generally predict an increase in strength of 2.2% K−1, which is much weaker than what would be expected from the increase in saturation vapor pressure of 6.5% K−1. Furthermore, it has been reported that the sensitivity of the hydrologic cycle to surface temperature differences caused by solar radiation is about 50% greater than by an equivalent difference induced by the greenhouse effect. Here we show that these sensitivities can be derived analytically from an extremely simple surface energy balance model that is constrained by the assumption that vertical convective transport within the atmosphere operates at maximum power. Using current climatic mean conditions, this model predicts a sensitivity of the hydrologic cycle of 2.2% K−1 to surface temperature induced by differences in the greenhouse effect, and a sensitivity of 3.2% K−1 for differences caused by absorbed solar radiation. These sensitivities can be explained by considering the changes in the surface energy balance in which the heating by solar radiation is partitioned equally into radiative and turbulent cooling at a state of maximum power of convective exchange. This explanation emphasizes the different roles that solar and terrestrial radiation play in the surface energy balance and hydrologic cycling that cannot be lumped together into a radiative forcing concept. We illustrate one implication of this explanation for the case of geoengineering, which aims to undo surface temperature differences by solar radiation management, but will nevertheless result in substantial differences in hydrologic cycling due to the difference in sensitivities. We conclude that the overall sensitivity of the hydrologic cycle to surface temperature can be understood and predicted by very simple physical considerations.

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