Budyko‐Based Long‐term Water and Energy Balance Closure in Global Watersheds from Earth Observations

Introduction: Obesity, a serious public health problem, occurs mainly when food consumption exceeds energy expenditure. Therefore, energy balance depends on the regulation of the hunger–satiety mechanism, which involves interconnection of the central nervous system and peripheral signals from the adipose tissue, pancreas and gastrointestinal tract, generating responses in short-term food intake and long-term energy balance. Increased body fat alters the gut- and adipose-tissue-derived hormone signaling, which promotes modifications in appetite-regulating hormones, decreasing satiety and increasing hunger senses. With the failure of conventional weight loss interventions (dietary treatment, exercise, drugs and lifestyle modifications), bariatric surgeries are well-accepted tools for the treatment of severe obesity, with long-term and sustained weight loss. Bariatric surgeries may cause weight loss due to restriction/malabsorption of nutrients from the anatomical alteration of the gastrointestinal tract that decreases energy intake, but also by other physiological factors associated with better results of the surgical procedure. Objective: This review discusses the neuroendocrine regulation of energy balance, with description of the predominant hormones and peptides involved in the control of energy balance in obesity and all currently available bariatric surgeries. Conclusions: According to the findings of our review, bariatric surgeries promote effective and sustained weight loss not only by reducing calorie intake, but also by precipitating changes in appetite control, satiation and satiety, and physiological changes in gut-, neuro- and adipose-tissue-derived hormone signaling.

Download Full-text

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.

Download Full-text

Energy balance measurements over a banana orchard in the Semiarid region in the Northeast of Brazil

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2009001100001 ◽

2009 ◽

Vol 44 (11) ◽

pp. 1365-1373 ◽

Cited By ~ 2

Author(s):

Carlos Antonio Costa dos Santos ◽

Bernardo Barbosa da Silva ◽

Tantravahi Venkata Ramana Rao ◽

Christopher Michael Usher Neale

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Eddy Covariance ◽

Heat Fluxes ◽

Irrigation District ◽

Semiarid Region ◽

Energy Balance Closure ◽

Wet Season ◽

Growing Seasons ◽

Eddy Covariance System

The objective of this work was to evaluate the reliability of eddy covariance measurements, analyzing the energy balance components, evapotranspiration and energy balance closure in dry and wet growing seasons, in a banana orchard. The experiment was carried out at a farm located within the irrigation district of Quixeré, in the Lower Jaguaribe basin, in Ceará state, Brazil. An eddy covariance system was used to measure the turbulent flux. An automatic weather station was installed in a grass field to obtain the reference evapotranspiration (ET0) from the combined FAO-Penman-Monteith method. Wind speed and vapor pressure deficit are the most important variables on the evaporative process in both growing seasons. In the dry season, the heat fluxes have a similar order of magnitude, and during the wet season the latent heat flux is the largest. The eddy covariance system had acceptable reliability in measuring heat flux, with actual evapotranspiration results comparing well with those obtained by using the water balance method. The energy balance closure had good results for the study area, with mean values of 0.93 and 0.86 for the dry and wet growing seasons respectively.

Download Full-text

Surface energy balance closure by the eddy-covariance method above three boreal forest stands and implications for the measurement of the CO2 flux

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2006.08.007 ◽

2006 ◽

Vol 140 (1-4) ◽

pp. 322-337 ◽

Cited By ~ 161

Author(s):

A.G. Barr ◽

K. Morgenstern ◽

T.A. Black ◽

J.H. McCaughey ◽

Z. Nesic

Keyword(s):

Energy Balance ◽

Surface Energy ◽

Boreal Forest ◽

Eddy Covariance ◽

Surface Energy Balance ◽

Co2 Flux ◽

Energy Balance Closure ◽

Forest Stands ◽

Eddy Covariance Method

Download Full-text

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

10.5194/hess-2016-76 ◽

2016 ◽

Cited By ~ 3

Author(s):

Nobuhle P. Majozi ◽

Chris M. Mannaerts ◽

Abel Ramoelo ◽

Renaud Mathieu ◽

Alecia Nickless ◽

...

Keyword(s):

Energy Balance ◽

Surface Energy ◽

Latent Heat ◽

Surface Energy Balance ◽

Heat Fluxes ◽

Surface Energy Budget ◽

Radiation Budget ◽

Energy Balance Closure ◽

Flux Tower ◽

The Impact

Abstract. Flux tower sites and data are in great demand to 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 for example assessment of evapotranspiration from land and vegetation surfaces using surface energy balance approaches. Surface energy budget methods for ET estimation rely to a large extend on the basic assumption of a surface energy balance closure, assuming the full conversion of net solar radiation reaching the land surface into soil heat conduction and turbulent fluxes, i.e. the sensible (or convection) and latent heat components of the energy balance. Evapotranspiration is the conversion of the latent heat exchange fraction of the balance. In this paper, the Skukuza flux tower data were analysed in order to verify their use for validation of satellite–based evapotranspiration methods, under development in South Africa.Data series from 2000 until 2014 were used in the analysis. The energy balance ratio (EBR) concept, defined as the ratio between the sum of the turbulent convective and latent heat fluxes and radiation minus soil heat was used. At first typical diurnal patterns of EB partitioning were derived for four different seasons, well illustrating how this savannah-type biome responses to the weather conditions. Also the particular behaviour of the EB components during sunrise and sunset conditions, being important but usually neglected periods of energy transitions and inversions were noted and analysed. Annual estimates of the surface energy balance and its components were generated, including an evaluation of the balance closure. The seasonal variations were also investigated as well as the impact of nocturnal observations on the overall EB behaviour.

Download Full-text

Long-term influence of feeding barley treated with lactic acid and heat on performance and energy balance in dairy cows

Archives of Animal Nutrition ◽

10.1080/1745039x.2016.1253226 ◽

2016 ◽

Vol 71 (1) ◽

pp. 54-66 ◽

Cited By ~ 1

Author(s):

Leonhard Gruber ◽

Annabella Khol-Parisini ◽

Elke Humer ◽

Sherief M. Abdel-Raheem ◽

Qendrim Zebeli

Keyword(s):

Lactic Acid ◽

Energy Balance ◽

Dairy Cows

Download Full-text

Energy balance closure in the Southwest Amazon forest site—a statistical approach

Theoretical and Applied Climatology ◽

10.1007/s00704-018-2548-8 ◽

2018 ◽

Vol 136 (3-4) ◽

pp. 1209-1219 ◽

Cited By ~ 1

Author(s):

Renata Gonçalves Aguiar ◽

Carlo Ralph De Musis ◽

Leonardo José Gonçalves Aguiar ◽

Mariano Martínez-Espinosa ◽

Graciela Redies Fischer

Keyword(s):

Energy Balance ◽

Statistical Approach ◽

Forest Site ◽

Amazon Forest ◽

Energy Balance Closure

Download Full-text

On the way to realistic large eddy simulations – A comparison of virtual measurements with CHEESEHEAD19 field measurements

10.5194/egusphere-egu21-2132 ◽

2021 ◽

Author(s):

Luise Wanner ◽

Sreenath Paleri ◽

Johannes Speidel ◽

Ankur Desai ◽

Matthias Sühring ◽

...

Keyword(s):

Energy Balance ◽

Eddy Covariance ◽

Field Measurements ◽

Transport Processes ◽

Large Eddy Simulations ◽

Surface Model ◽

Closure Problem ◽

Energy Balance Closure ◽

Large Eddy ◽

Eddy Covariance Measurements

<p>Large-eddy simulations are useful tools to study transport processes by mesoscale structures in the atmospheric boundary layer, since in contrast to single-tower eddy covariance measurements, they provide not only temporally but also spatially highly resolved information. Therefore, they are well suited to study the energy balance closure problem, for which the mesoscale transport of latent and sensible heat, triggered by heterogeneous ecosystems, is suspected to be a major cause. However, this requires simulations that are as realistic as possible and thus allow a comparison of real measurements in the field and virtual measurements in the simulation.<br>During the Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors (CHEESEHEAD) experiment in the summer of 2019, a heterogeneous 10x10 square km domain was intensively sampled across scales. This data offers a unique possibility to set up large-eddy simulations with realistic surface heterogeneity. We use PALM to simulate two days and an area of 40 by 40 square kilometers incorporating the CHEESEHEAD site. The large scale atmospheric forcings to inform the boundary conditions are determined from the NCEP HRRR product. As the lower boundary condition, we use a soil and land-surface model coupled with a plant-canopy model, which we adapt to the CHEESEHEAD area based on ground-based and airborne measurements of plant physiological data.<br>In this study, we investigate how well the simulations match with real measurements by comparing simulated profiles and virtual tower measurements with field measurements from radiosonde ascents, lidar measurements of three-dimensional wind and water vapor, eddy-covariance measurements from the 400 meter tower in the center of the study domain, as well as from typical eddy-covariance stations distributed through the study area. This way, we investigate how realistic the simulations actually are and to what extent the knowledge gained from them concerning the energy balance closure problem can be transferred to field measurements.</p>

Download Full-text