Balanço de Energia à Superfície para a Cidade de Patos - PB Usando Técnicas de Sensoriamento Remoto (Surface Energy Balance for the Patos City-PB Using Remote Sensing Techniques)

O principal objetivo deste trabalho foi quantificar os principais componentes do balanço de energia à superfície da cidade de Patos- PB utilizando-se técnicas de sensoriamento remoto a partir de imagens do TM Landsat-5 e aplicação do algoritmo SEBAL para determinar os componentes do balanço de energia à superfície. Os resultados mostraram que o saldo de radiação (Rn) variou de modo similar ao determinado na literatura; os valores do fluxo de calor sensível (H) apresentaram alta variabilidade espacial, coerentes com a distribuição espacial de H sobre a área estudada. O fluxo de calor latente (LE) apresentou os maiores valores para os corpos d’água e área vegetadas e menores valores para a zona urbana e solo exposto, devido à sua baixa disponibilidade de umidade, resultando em valores de evapotranspiração diária variando entre 0,1 e 12 mm dia-1. A imagem de satélite mostrou que a modificação do uso e da cobertura do solo contribui para o balanço de energia à superfície de uma área urbana. AbstractThe main objective of this study was to quantify the major components of the energy balance at the surface of the city of Patos-PB using remote sensing images from Landsat-5 TM and application of SEBAL algorithm to determine the components of the surface energy balance. The findings showed that the net radiation (Rn) ranged similarly to those presented in the literature; the values of the sensible heat flux (H) showed high spatial variability, consistent in the spatial distribution of H in the area studied. The latent heat flux (LE) showed the highest values for the water bodies and vegetated area, and lowest values for urban areas and bare soil, due to its low availability of moisture, resulting in daily evaporation values from 0.1 to 12 mm day-1. The satellite image showed that the change of use and land cover contributes to the surface energy balance of an urban area.

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Evaluation of an extreme-condition-inverse calibration remote sensing model for mapping energy balance fluxes in arid riparian areas

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-11-13479-2014 ◽

2014 ◽

Vol 11 (12) ◽

pp. 13479-13539 ◽

Cited By ~ 3

Author(s):

S.-H. Hong ◽

J. M. H. Hendrickx ◽

J. Kleissl ◽

R. G. Allen ◽

W. G. M. Bastiaanssen ◽

...

Keyword(s):

Remote Sensing ◽

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Surface Energy Balance ◽

Sensible Heat Flux ◽

Extreme Condition ◽

Accurate Information ◽

Riparian Areas ◽

Owens Valley

Abstract. Accurate information on the distribution of the surface energy balance components in arid riparian areas is needed for sustainable management of water resources as well as for a better understanding of water and heat exchange processes between the land surface and the atmosphere. Since the spatial and temporal distributions of these fluxes over large areas are difficult to determine from ground measurements alone, their prediction from remote sensing data is very attractive as it enables large area coverage and a high repetition rate. In this study the Surface Energy Balance Algorithm for Land (SEBAL) was used to estimate all the energy balance components in the arid riparian areas of the Middle Rio Grande Basin (New Mexico), San Pedro Basin (Arizona), and Owens Valley (California). We compare instantaneous and daily SEBAL fluxes derived from Landsat TM images to surface-based measurements with eddy covariance flux towers. This study presents evidence that SEBAL yields reliable estimates for actual evapotranspiration rates in riparian areas of the southwestern United States. The great strength of the SEBAL method is its internal calibration procedure that eliminates most of the bias in latent heat flux at the expense of increased bias in sensible heat flux.

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Analysing surface energy balance closure and partitioning over a semi-arid savanna FLUXNET site in Skukuza, Kruger National Park, South Africa

Hydrology and Earth System Sciences ◽

10.5194/hess-21-3401-2017 ◽

2017 ◽

Vol 21 (7) ◽

pp. 3401-3415 ◽

Cited By ~ 18

Author(s):

Nobuhle P. Majozi ◽

Chris M. Mannaerts ◽

Abel Ramoelo ◽

Renaud Mathieu ◽

Alecia Nickless ◽

...

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Latent Heat ◽

Surface Energy Balance ◽

Sensible Heat Flux ◽

Dry Season ◽

Energy Balance Closure ◽

Net Radiation ◽

Wet Season

Abstract. Flux towers provide essential terrestrial climate, water, and radiation budget information needed for environmental monitoring and evaluation of climate change impacts on ecosystems and society in general. They are also intended for calibration and validation of satellite-based Earth observation and monitoring efforts, such as assessment of evapotranspiration from land and vegetation surfaces using surface energy balance approaches. In this paper, 15 years of Skukuza eddy covariance data, i.e. from 2000 to 2014, were analysed for surface energy balance closure (EBC) and partitioning. The surface energy balance closure was evaluated using the ordinary least squares regression (OLS) of turbulent energy fluxes (sensible (H) and latent heat (LE)) against available energy (net radiation (Rn) less soil heat (G)), and the energy balance ratio (EBR). Partitioning of the surface energy during the wet and dry seasons was also investigated, as well as how it is affected by atmospheric vapour pressure deficit (VPD), and net radiation. After filtering years with low-quality data (2004–2008), our results show an overall mean EBR of 0.93. Seasonal variations of EBR also showed the wet season with 1.17 and spring (1.02) being closest to unity, with the dry season (0.70) having the highest imbalance. Nocturnal surface energy closure was very low at 0.26, and this was linked to low friction velocity during night-time, with results showing an increase in closure with increase in friction velocity. The energy partition analysis showed that sensible heat flux is the dominant portion of net radiation, especially between March and October, followed by latent heat flux, and lastly the soil heat flux, and during the wet season where latent heat flux dominated sensible heat flux. An increase in net radiation was characterized by an increase in both LE and H, with LE showing a higher rate of increase than H in the wet season, and the reverse happening during the dry season. An increase in VPD is correlated with a decrease in LE and increase in H during the wet season, and an increase in both fluxes during the dry season.

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Updated cloud physics in a regional atmospheric climate model improves the modelled surface energy balance of Antarctica

The Cryosphere ◽

10.5194/tc-8-125-2014 ◽

2014 ◽

Vol 8 (1) ◽

pp. 125-135 ◽

Cited By ~ 44

Author(s):

J. M. van Wessem ◽

C. H. Reijmer ◽

J. T. M. Lenaerts ◽

W. J. van de Berg ◽

M. R. van den Broeke ◽

...

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Surface Energy Balance ◽

Climate Model ◽

Sensible Heat Flux ◽

Sensible Heat ◽

Ice Cloud ◽

Long Wave ◽

Regional Atmospheric Climate Model

Abstract. In this study the effects of changes in the physics package of the regional atmospheric climate model RACMO2 on the modelled surface energy balance, near-surface temperature and wind speed of Antarctica are presented. The physics package update primarily consists of an improved turbulent and radiative flux scheme and a revised cloud scheme that includes a parameterisation for ice cloud super-saturation. The ice cloud super-saturation has led to more moisture being transported onto the continent, resulting in more and optically thicker clouds and more downward long-wave radiation. Overall, the updated model better represents the surface energy balance, based on a comparison with >750 months of data from nine automatic weather stations located in East Antarctica. Especially the representation of the turbulent sensible heat flux and net long-wave radiative flux has improved with a decrease in biases of up to 40%. As a result, modelled surface temperatures have increased and the bias, when compared to 10 m snow temperatures from 64 ice-core observations, has decreased from −2.3 K to −1.3 K. The weaker surface temperature inversion consequently improves the representation of the sensible heat flux, whereas wind speed biases remain unchanged. However, significant model biases remain, partly because RACMO2 at a resolution of 27 km is unable to resolve steep topography.

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Intercomparison of Spatially Distributed Models for Predicting Surface Energy Flux Patterns during SMACEX

Journal of Hydrometeorology ◽

10.1175/jhm468.1 ◽

2005 ◽

Vol 6 (6) ◽

pp. 941-953 ◽

Cited By ~ 22

Author(s):

Wade T. Crow ◽

Fuqin Li ◽

William P. Kustas

Keyword(s):

Remote Sensing ◽

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Surface Temperature ◽

Energy Flux ◽

Land Surface ◽

Sensible Heat Flux ◽

Energy Fluxes ◽

Spatially Distributed

Abstract The treatment of aerodynamic surface temperature in soil–vegetation–atmosphere transfer (SVAT) models can be used to classify approaches into two broad categories. The first category contains models utilizing remote sensing (RS) observations of surface radiometric temperature to estimate aerodynamic surface temperature and solve the terrestrial energy balance. The second category contains combined water and energy balance (WEB) approaches that simultaneously solve for surface temperature and energy fluxes based on observations of incoming radiation, precipitation, and micrometeorological variables. To date, few studies have focused on cross comparing model predictions from each category. Land surface and remote sensing datasets collected during the 2002 Soil Moisture–Atmosphere Coupling Experiment (SMACEX) provide an opportunity to evaluate and intercompare spatially distributed surface energy balance models. Intercomparison results presented here focus on the ability of a WEB-SVAT approach [the TOPmodel-based Land–Atmosphere Transfer Scheme (TOPLATS)] and an RS-SVAT approach [the Two-Source Energy Balance (TSEB) model] to accurately predict patterns of turbulent energy fluxes observed during SMACEX. During the experiment, TOPLATS and TSEB latent heat flux predictions match flux tower observations with root-mean-square (rms) accuracies of 67 and 63 W m−2, respectively. TSEB predictions of sensible heat flux are significantly more accurate with an rms accuracy of 22 versus 46 W m−2 for TOPLATS. The intercomparison of flux predictions from each model suggests that modeling errors for each approach are sufficiently independent and that opportunities exist for improving the performance of both models via data assimilation and model calibration techniques that integrate RS- and WEB-SVAT energy flux predictions.

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Evaluation and Parameter-Sensitivity Study of a Single-Layer Urban Canopy Model (SLUCM) with Measurements in Nanjing, China

Journal of Hydrometeorology ◽

10.1175/jhm-d-13-0129.1 ◽

2014 ◽

Vol 15 (3) ◽

pp. 1078-1090 ◽

Cited By ~ 9

Author(s):

Wenjing Zhao ◽

Ning Zhang ◽

Jianning Sun ◽

Jun Zou

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Surface Energy Balance ◽

Sensible Heat Flux ◽

Single Layer ◽

Urban Canopy ◽

Sensible Heat ◽

Urban Canopy Model ◽

Canopy Model

Abstract An offline single-layer urban canopy model (SLUCM) was driven by the surface energy balance observations in winter in Nanjing, China, to evaluate the capability of the model to simulate the urban surface energy balance. The results of the evaluation suggest that the simulated daytime net radiation is approximately 20% lower than the observed and display relatively high systematic error, which is due to the relatively poor capacity of the model to simulate the daytime longwave radiation (which is underestimated by approximately 35%). By contrast, the simulated sensible heat flux shows mainly unsystematic error. Moreover, the one-at-a-time method is used to conduct a sensitivity analysis of the model parameters. The sensitivity analysis demonstrates that the major factors affecting the surface energy balance are the albedo, the thermal conductivity, and the roof and wall volumetric heat capacity. The influences of the shape of the street canyon and the average height of buildings are relatively weaker. The effects of the albedo on the fluxes are nearly linear. The effects of the thermal parameters are approximately logarithmic. Furthermore, the simulated sensible heat flux in the SLUCM is insensitive to the morphological parameters of the buildings.

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The surface energy balance in a cold-arid permafrost environment, Ladakh Himalaya, India

10.5194/tc-2019-286 ◽

2020 ◽

Author(s):

John Mohd Wani ◽

Renoj J. Thayyen ◽

Chandra Shekhar Prasad Ojha ◽

Stephan Gruber

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Latent Heat ◽

Latent Heat Flux ◽

Surface Energy Balance ◽

Sensible Heat Flux ◽

Longwave Radiation ◽

Sensible Heat ◽

The Alps

Abstract. Cryosphere of the cold-arid trans-Himalayan region is unique with its significant permafrost cover. While the information on the permafrost characteristics and its extent started emerging, the governing energy regimes of this cryosphere region is of particular interest. This paper present the results of Surface Energy Balance (SEB) studies carried out in the upper Ganglass catchment in the Ladakh region of India, which feed directly to the River Indus. The point SEB is estimated using the one-dimensional mode of GEOtop model from 1 September 2015 to 31 August 2017 at 4727 m a.s.l elevation. The model is evaluated using field monitored radiation components, snow depth variations and one-year near-surface ground temperatures and showed good agreement with the respective simulated values. The study site has an air temperature range of −23.7 to 18.1 °C with a mean annual average temperature (MAAT) of −2.5 and ground surface temperature range of −9.8 to 19.1 °C. For the study period, the surface energy balance characteristics of the cold-arid site show that the net radiation was the major component with mean value of 28.9 W m−2 followed by sensible heat flux (13.5 W m−2) and latent heat flux (12.8 W m−2), and the ground heat flux was equal to 0.4 W m−2. The partitioning of energy balance during the study period shows that 47 % of Rn was converted into H, 44 % into LE, 1 % into G and 7 % for melting of seasonal snow. Both the study years experienced distinctly different, low and high snow regime. Key differences due to this snow regime change in surface energy balance characteristics were observed during peak summer (July–August). The latent heat flux was higher (lower) during this period with 39 W m−2 (11 W m−2) during high (low) snow years. The study also shows that the sensible heat flux during the early summer season (May, June) of the high (low) snow was much smaller (higher) −3.4 W m−2 (36.1 W m−2). During the study period, snow cover builds up in the catchment initiated by the last week of December facilitating the ground cooling by almost three months (October to December) of sub-zero temperatures up to −20 °C providing a favourable environment for permafrost. It is observed that the Ladakh region have a very low relative humidity in the range of 43 % as compared to, e.g., ~ 70 % in the Alps facilitating lower incoming longwave radiation and strongly negative net longwave radiation averaging ~ −90 W m−2 compared to −40 W m−2 in the Alps. Hence, the high elevation cold-arid region land surfaces could be overall colder than the locations with more RH such as the Alps. Further, it is apprehended that high incoming shortwave radiation in the region may be facilitating enhanced cooling of wet valley bottom surfaces as a result of stronger evaporation.

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Analysing surface energy balance closure and partitioning over a semi-arid savanna FLUXNET site in Skukuza, Kruger National Park, South Africa

10.5194/hess-2016-685 ◽

2017 ◽

Author(s):

Nobuhle P. Majozi ◽

Chris M. Mannaerts ◽

Abel Ramoelo ◽

Renaud Mathieu ◽

Alecia Nickless ◽

...

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Latent Heat ◽

Friction Velocity ◽

Surface Energy Balance ◽

Sensible Heat Flux ◽

Energy Balance Closure ◽

Net Radiation ◽

Wet Season

Abstract. Flux towers provide essential terrestrial climate, water and radiation budget information needed for environmental monitoring and evaluation of climate change impacts on ecosystems and society in general. They are also intended for calibration and validation of satellite-based earth observation and monitoring efforts, such as assessment of evapotranspiration from land and vegetation surfaces using surface energy balance approaches. In this paper, 15 years of Skukuza eddy covariance data, i.e. from 2000 to 2014, were analysed for surface energy balance closure (EBC) and partitioning. The surface energy balance closure was evaluated using the ordinary least squares regression (OLS) of turbulent energy fluxes (sensible (H) and latent heat (LE)) against available energy (net radiation (Rn) less soil heat (G)), and the energy balance ratio (EBR). Partitioning of the surface energy during the wet and dry seasons was investigated, as well as how it is affected by atmospheric vapor pressure deficit (VPD), and net radiation. After filtering years with bad data (2004–2008), our results show an overall mean EBR of 0.93. Seasonal variations of EBR also showed summer (0.98) and spring (1.02) were closest to unity, with winter (0.70) having the least closure. Nocturnal surface energy closure was very low at 0.11, and this was linked to low friction velocity during night-time, with results showing an increase in closure with increase in friction velocity. The surface energy partitioning of this savanna ecosystem showed that sensible heat flux dominated the energy partitioning between March and October, followed by latent heat flux, and lastly the soil heat flux, and during the wet season where latent heat flux dominated the sensible heat flux. An increase in net radiation was characterized by an increase in both LE and H, with LE showing a higher rate of increase than H in the wet season, and the reverse happening during the dry season. An increase in VPD is characterized by a decrease in LE and increase in H during the wet season, and an increase of both fluxes during the dry season.

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The Analytical Objective Hysteresis Model (AnOHM v1.0): Methodology to Determine Bulk Storage Heat Flux Coefficients

10.5194/gmd-2016-300 ◽

2017 ◽

Cited By ~ 1

Author(s):

Ting Sun ◽

Zhi-Hua Wang ◽

Walter Oechel ◽

Sue Grimmond

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Urban Areas ◽

Surface Energy Balance ◽

Bowen Ratio ◽

Stochastic Approach ◽

Wave Radiation ◽

Hysteresis Model ◽

Advection Diffusion Equation

Abstract. The net storage heat flux is not only a large part of the urban surface energy balance (SEB) but its determination remains a significant challenge. The diurnal hysteresis behaviour found between the net storage heat flux (ΔQS) and net all-wave radiation (Q*) has been captured in the Objective Hysteresis Model (OHM) parametrization of ΔQS. Although, successfully used in urban areas, the limited availability of coefficients for OHM hampers application. To facilitate use, and enhance physical interpretations of the OHM coefficients, an analytical solution of the 1-dimensional advection-diffusion equation of coupled heat and liquid water transport in conjunction with the SEB is conducted, allowing development of AnOHM (Analytical Objective Hysteresis Model). A sensitivity test of AnOHM to surface properties and hydrometeorological forcing is undertaken using a stochastic approach (the Subset Simulation). From this albedo, Bowen ratio and bulk transfer coefficient, solar radiation and wind speed are identified as being critical. AnOHM, driven by local meteorological conditions at five different land use areas, is shown to simulate the ΔQS flux well (RMSE values of ~30 W m−2). The intra-annual dynamics of OHM coefficients to are explored which offers significant potential to enhance modelling of the surface energy balance over a wider range of conditions.

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The secret life of ice sails

Journal of Glaciology ◽

10.1017/jog.2017.72 ◽

2017 ◽

Vol 63 (242) ◽

pp. 1049-1062 ◽

Cited By ~ 1

Author(s):

GEOFFREY W. EVATT ◽

CHRISTOPH MAYER ◽

AMY MALLINSON ◽

I. DAVID ABRAHAMS ◽

MATTHIAS HEIL ◽

...

Keyword(s):

Heat Flux ◽

Sensitivity Analysis ◽

Steady State ◽

Energy Balance ◽

Surface Energy ◽

Surface Energy Balance ◽

Sensible Heat Flux ◽

Balance Model ◽

Sensible Heat ◽

Glacier Surface

ABSTRACTWe present the first dedicated study into the phenomenon of ice sails. These are clean ice structures that protrude from the surface of a small number of debris-covered glaciers and can grow to heights of over 25 m. We draw together what is known about them from the academic/exploration literature and then analyse imagery. We show here that ice sails can develop by one of two mechanisms, both of which require clean ice to become surrounded by debris-covered ice, where the debris layer is shallow enough for the ice beneath it to melt faster than the clean ice. Once formed, ice sails can persist for decades, in an apparently steady state, before debris layer thickening eventually causes a reversal in the relative melt rates and the ice sails decay to merge back with the surrounding glacier surface. We support our image-based analysis with a surface energy-balance model and show that it compares well with available observations from Baltoro Glacier in the Karakoram. A sensitivity analysis of the model is performed and confirms the results from our empirical study that ice sails require a relatively high evaporative heat flux and/or a relatively low sensible heat flux in order to exist.

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The role of aerodynamic resistance in thermal remote sensing-based evapotranspiration models

10.5194/egusphere-egu21-2186 ◽

2021 ◽

Author(s):

Ivonne Trebs ◽

Kaniska Mallick ◽

Nishan Bhattarai ◽

Mauro Sulis ◽

James Cleverly ◽

...

Keyword(s):

Remote Sensing ◽

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Surface Temperature ◽

Surface Energy Balance ◽

Aerodynamic Resistance ◽

Atmospheric Stability ◽

Semi Arid

&#8216;Aerodynamic resistance&#8217; (hereafter ra) is a preeminent variable in the modelling of evapotranspiration (ET), and its accurate quantification plays a critical role in determining the performance and consistency of thermal remote sensing-based surface energy balance (SEB) models for estimating ET at local to regional scales. Atmospheric stability links ra with land surface temperature (LST) and the representation of their interactions in the SEB models determines the accuracy of ET estimates.The present study investigates the influence of ra and its relation to LST uncertainties on the performance of three structurally different SEB models by combining nine OzFlux eddy covariance datasets from 2011 to 2019 from sites of different aridity in Australia with MODIS Terra and Aqua LST and leaf area index (LAI) products. Simulations of the latent heat flux (LE, energy equivalent of ET in W/m2) from the SPARSE (Soil Plant Atmosphere and Remote Sensing Evapotranspiration), SEBS (Surface Energy Balance System) and STIC (Surface Temperature Initiated Closure) models forced with MODIS LST, LAI, and in-situ meteorological datasets were evaluated using observed flux data across water-limited (semi-arid and arid) and radiation-limited (mesic) ecosystems.Our results revealed that the three models tend to overestimate instantaneous LE in the water-limited shrubland, woodland and grassland ecosystems by up to 60% on average, which was caused by an underestimation of the sensible heat flux (H). LE overestimation was associated with discrepancies in ra retrievals under conditions of high atmospheric instability, during which errors in LST (expressed as the difference between MODIS LST and in-situ LST) apparently played a minor role. On the other hand, a positive bias in LST coincides with low ra and causes slight underestimation of LE at the water-limited sites. The impact of ra on the LE residual error was found to be of the same magnitude as the influence of errors in LST in the semi-arid ecosystems as indicated by variable importance in projection (VIP) coefficients from partial least squares regression above unity. In contrast, our results for mesic forest ecosystems indicated minor dependency on ra for modelling LE (VIP<0.4), which was due to a higher roughness length and lower LST resulting in dominance of mechanically generated turbulence, thereby diminishing the importance of atmospheric stability in the determination of ra.

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