scholarly journals A Critical Evaluation on the Role of Aerodynamic and Canopy–Surface Conductance Parameterization in SEB and SVAT Models for Simulating Evapotranspiration: A Case Study in the Upper Biebrza National Park Wetland in Poland

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1753 ◽  
Author(s):  
Kaniska Mallick ◽  
Loise Wandera ◽  
Nishan Bhattarai ◽  
Renaud Hostache ◽  
Malgorzata Kleniewska ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
National Park ◽  
Surface Energy Balance ◽  
Critical Evaluation ◽  
Surface Conductance ◽  
Eastern European ◽  
Balance System ◽  
North Eastern ◽  
The Impact

Evapotranspiration (ET) estimation through the surface energy balance (SEB) and soil-vegetation-atmosphere-transfer (SVAT) models are uncertain due to the empirical parameterizations of the aerodynamic and canopy-substrate conductances (gA and gS) for heat and water vapor transfers. This study critically assessed the impact of conductance parameterizations on ET simulation using three structurally different SEB and SVAT models for an ecologically important North-Eastern European wetland, Upper Biebrza National Park (UBNP) in two consecutive years 2015 and 2016. A pronounced ET underestimation (mean bias −0.48 to −0.68 mm day−1) in SEBS (Surface Energy Balance System) was associated with an overestimation of gA due to uncertain parameterization of momentum roughness length and bare soil’s excess resistance to heat transfer (kB−1) under low vegetation cover. The systematic ET overestimation (0.65–0.80 mm day−1) in SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes) was attributed to the overestimation of both the conductances. Conductance parameterizations in SEBS and SCOPE appeared to be very sensitive to the general ecohydrological conditions, with a tendency of overestimating gA (gS) under humid (arid) conditions. Low ET bias in the analytical STIC (Surface Temperature Initiated Closure) model as compared to SEBS/SCOPE indicated the critical need for calibration-free conductance parameterizations for improved ET estimation.

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

2016 ◽  
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.

scholarly journals Improving Meteorological Input for Surface Energy Balance System Utilizing Mesoscale Weather Research and Forecasting Model for Estimating Daily Actual Evapotranspiration

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 9 ◽  
Author(s):  
Dakang Wang ◽  
Yulin Zhan ◽  
Tao Yu ◽  
Yan Liu ◽  
Xiaomei Jin ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Interpolation Method ◽  
Meteorological Data ◽  
Meteorological Station ◽  
Weather Research And Forecasting ◽  
Balance System ◽  
Meteorological Input ◽  
Sebs Model

Using Surface Energy Balance System (SEBS) to estimate actual evapotranspiration (ET) on a regional scale generally uses gridded meteorological data by interpolating data from meteorological stations with mathematical interpolation. The heterogeneity of underlying surfaces cannot be effectively considered when interpolating meteorological station measurements to gridded data only by mathematical interpolation. This study aims to highlight the improvement of modeled meteorological data from the Weather Research and Forecasting (WRF) mesoscale numerical model which fully considers the heterogeneity of underlying surfaces over the data from mathematical interpolation method when providing accurate meteorological input for SEBS model. Meteorological data at 1 km resolution in the Hotan Oasis were simulated and then were put into SEBS model to estimate the daily actual ET. The accuracy of WRF simulation was evaluated through comparison with data collected at the meteorological station. Results found that the WRF-simulated wind speed, air temperature, relative humidity and surface pressure correlate well with the meteorological stations measurements (R2 are 0.628, 0.8242, 0.8089 and 0.8915, respectively). Comparison between ET calculated using the meteorological data simulated from the WRF (ETa-WRF) and meteorological data interpolated from measurements at met stations (ETa-STA) showed that ETa-WRF could better reflect the ET difference between different land cover, and capture the vegetation growing trend, especially in areas with sparse vegetation, where ETa-STA intends to overestimate. In addition, ETa-WRF has less noise in barren areas compared to ETa-STA. Our findings suggest that WRF can provide more reliable meteorological input for SEBS model than mathematical interpolation method.

scholarly journals Potential evaporation estimation through an unstressed surface-energy balance and its sensitivity to climate change

2013 ◽  
Vol 17 (11) ◽  
pp. 4625-4639 ◽  
Author(s):  
A. Barella-Ortiz ◽  
J. Polcher ◽  
A. Tuzet ◽  
K. Laval
Keyword(s):  
Climate Change ◽  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Aerodynamic Resistance ◽  
Neutral Stability ◽  
Potential Evaporation ◽  
Time Step ◽  
Humidity Gradient ◽  
The Impact

Abstract. Potential evaporation (ETP) is a basic input for many hydrological and agronomic models, as well as a key variable in most actual evaporation estimations. It has been approached through several diffusive and energy balance methods, out of which the Penman–Monteith equation is recommended as the standard one. In order to deal with the diffusive approach, ETP must be estimated at a sub-diurnal frequency, as currently done in land surface models (LSMs). This study presents an improved method, developed in the ORCHIDEE LSM, which consists of estimating ETP through an unstressed surface-energy balance (USEB method). The results confirm the quality of the estimation which is currently implemented in the model (Milly, 1992). The ETP underlying the reference evaporation proposed by the Food and Agriculture Organization, FAO, (computed at a daily time step) has also been analysed and compared. First, a comparison for a reference period under current climate conditions shows that USEB and FAO's ETP estimations differ, especially in arid areas. However, they produce similar values when the FAO's assumption of neutral stability conditions is relaxed, by replacing FAO's aerodynamic resistance by that of the model's. Furthermore, if the vapour pressure deficit (VPD) estimated for the FAO's equation, is substituted by ORCHIDEE's VPD or its humidity gradient, the agreement between the daily mean estimates of ETP is further improved. In a second step, ETP's sensitivity to climate change is assessed by comparing trends in these formulations for the 21st century. It is found that the USEB method shows a higher sensitivity than the FAO's. Both VPD and the model's humidity gradient, as well as the aerodynamic resistance have been identified as key parameters in governing ETP trends. Finally, the sensitivity study is extended to two empirical approximations based on net radiation and mass transfer (Priestley–Taylor and Rohwer, respectively). The sensitivity of these ETP estimates is compared to the one provided by USEB to test if simplified equations are able to reproduce the impact of climate change on ETP.

scholarly journals The Surface Energy Balance System (SEBS) for estimation of turbulent heat fluxes

2002 ◽  
Vol 6 (1) ◽  
pp. 85-100 ◽  
Author(s):  
Z. Su
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Heat Fluxes ◽  
Physical Parameters ◽  
Turbulent Heat ◽  
Evaporative Fraction ◽  
Balance System ◽  
Turbulent Heat Fluxes

Abstract. A Surface Energy Balance System (SEBS) is proposed for the estimation of atmospheric turbulent fluxes and evaporative fraction using satellite earth observation data, in combination with meteorological information at proper scales. SEBS consists of: a set of tools for the determination of the land surface physical parameters, such as albedo, emissivity, temperature, vegetation coverage etc., from spectral reflectance and radiance measurements; a model for the determination of the roughness length for heat transfer; and a new formulation for the determination of the evaporative fraction on the basis of energy balance at limiting cases. Four experimental data sets are used to assess the reliabilities of SEBS. Based on these case studies, SEBS has proven to be capable to estimate turbulent heat fluxes and evaporative fraction at various scales with acceptable accuracy. The uncertainties in the estimated heat fluxes are comparable to in-situ measurement uncertainties. Keywords: Surface energy balance, turbulent heat flux, evaporation, remote sensing

scholarly journals The Impact of Föhn Winds on Surface Energy Balance During the 2010-2011 Melt Season Over Larsen C Ice Shelf, Antarctica

2017 ◽  
Vol 122 (22) ◽  
pp. 12,062-12,076 ◽  
Author(s):  
J. C. King ◽  
A. Kirchgaessner ◽  
S. Bevan ◽  
A. D. Elvidge ◽  
P. Kuipers Munneke ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Ice Shelf ◽  
The Impact

scholarly journals Regional evapotranspiration from an image-based implementation of the Surface Temperature Initiated Closure (STIC1.2) model and its validation across an aridity gradient in the conterminous US

2018 ◽  
Vol 22 (4) ◽  
pp. 2311-2341 ◽  
Author(s):  
Nishan Bhattarai ◽  
Kaniska Mallick ◽  
Nathaniel A. Brunsell ◽  
Ge Sun ◽  
Meha Jain
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Temperature ◽  
Land Surface ◽  
Surface Energy Balance ◽  
Regional Scale ◽  
Absolute Error ◽  
Error Statistics ◽  
Aridity Gradient ◽  
Balance System

Abstract. Recent studies have highlighted the need for improved characterizations of aerodynamic conductance and temperature (gA and T0) in thermal remote-sensing-based surface energy balance (SEB) models to reduce uncertainties in regional-scale evapotranspiration (ET) mapping. By integrating radiometric surface temperature (TR) into the Penman–Monteith (PM) equation and finding analytical solutions of gA and T0, this need was recently addressed by the Surface Temperature Initiated Closure (STIC) model. However, previous implementations of STIC were confined to the ecosystem-scale using flux tower observations of infrared temperature. This study demonstrates the first regional-scale implementation of the most recent version of the STIC model (STIC1.2) that integrates the Moderate Resolution Imaging Spectroradiometer (MODIS) derived TR and ancillary land surface variables in conjunction with NLDAS (North American Land Data Assimilation System) atmospheric variables into a combined structure of the PM and Shuttleworth–Wallace (SW) framework for estimating ET at 1 km × 1 km spatial resolution. Evaluation of STIC1.2 at 13 core AmeriFlux sites covering a broad spectrum of climates and biomes across an aridity gradient in the conterminous US suggests that STIC1.2 can provide spatially explicit ET maps with reliable accuracies from dry to wet extremes. When observed ET from one wet, one dry, and one normal precipitation year from all sites were combined, STIC1.2 explained 66 % of the variability in observed 8-day cumulative ET with a root mean square error (RMSE) of 7.4 mm/8-day, mean absolute error (MAE) of 5 mm/8-day, and percent bias (PBIAS) of −4 %. These error statistics showed relatively better accuracies than a widely used but previous version of the SEB-based Surface Energy Balance System (SEBS) model, which utilized a simple NDVI-based parameterization of surface roughness (zOM), and the PM-based MOD16 ET. SEBS was found to overestimate (PBIAS = 28 %) and MOD16 was found to underestimate ET (PBIAS = −26 %). The performance of STIC1.2 was better in forest and grassland ecosystems as compared to cropland (20 % underestimation) and woody savanna (40 % overestimation). Model inter-comparison suggested that ET differences between the models are robustly correlated with gA and associated roughness length estimation uncertainties which are intrinsically connected to TR uncertainties, vapor pressure deficit (DA), and vegetation cover. A consistent performance of STIC1.2 in a broad range of hydrological and biome categories, as well as the capacity to capture spatio-temporal ET signatures across an aridity gradient, points to the potential for this simplified analytical model for near-real-time ET mapping from regional to continental scales.

scholarly journals Influences of tidal energy advection on the surface energy balance in a mangrove forest

2012 ◽  
Vol 9 (8) ◽  
pp. 11739-11765 ◽  
Author(s):  
J. G. Barr ◽  
J. D. Fuentes ◽  
M. S. DeLonge ◽  
T. L. O'Halloran ◽  
D. Barr ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Mangrove Forest ◽  
Surface Energy Balance ◽  
Energy Transport ◽  
Tidal Energy ◽  
Water Levels ◽  
Energy Output ◽  
Tidal Flows ◽  
The Impact

Abstract. Mangrove forests are ecosystems susceptible to changing water levels and temperatures due to climate change as well as perturbations resulting from tropical storms. Numerical models can be used to project mangrove forest responses to regional and global environmental changes, and the reliability of these models depends on surface energy balance closure. However, for tidal ecosystems, the surface energy balance is complex because the energy transport associated with tidal activity remains poorly understood. This study aimed to quantify impacts of tidal flows on energy dynamics within a mangrove ecosystem. To address the research objective, an intensive study was conducted in a mangrove forest located along the Shark River in the Everglades National Park, FL. Forest-atmosphere energy exchanges were quantified with an eddy covariance system deployed on a flux tower. The lateral energy transport associated with tidal activity was calculated based on a coupled mass and energy balance approach. The mass balance included tidal flows and accumulation of water on the forest floor. The energy balance included temporal changes in enthalpy, resulting from tidal flows and temperature changes in the water column. By serving as a net sink or a source of available energy, tidal flows reduced the impact of high radiational loads on the mangrove forest. Including tidal energy advection in the surface energy balance improved the 30-min daytime energy closure from 73% to 82% over the study period. Also, the cumulative sum of energy output improved from 79% to 91% of energy input during the study period. Results indicated that tidal inundation provides an important mechanism for heat removal and that tidal exchange should be considered in surface energy budgets of coastal ecosystems. Results also demonstrated the importance of including tidal energy advection in mangrove biophysical models that are used for predicting ecosystem response to changing climate and regional freshwater management practices.

scholarly journals The influence of föhn winds on annual and seasonal surface melt on the Larsen C Ice Shelf, Antarctica

2020 ◽  
Vol 14 (11) ◽  
pp. 4165-4180
Author(s):  
Jenny V. Turton ◽  
Amélie Kirchgaessner ◽  
Andrew N. Ross ◽  
John C. King ◽  
Peter Kuipers Munneke
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Model Driven ◽  
Area Of Interest ◽  
Surface Melt ◽  
The Individual ◽  
The Impact

Abstract. Warm, dry föhn winds are observed over the Larsen C Ice Shelf year-round and are thought to contribute to the continuing weakening and collapse of ice shelves on the eastern Antarctic Peninsula (AP). We use a surface energy balance (SEB) model, driven by observations from two locations on the Larsen C Ice Shelf and one on the remnants of Larsen B, in combination with output from the Antarctic Mesoscale Prediction System (AMPS), to investigate the year-round impact of föhn winds on the SEB and melt from 2009 to 2012. Föhn winds have an impact on the individual components of the surface energy balance in all seasons and lead to an increase in surface melt in spring, summer and autumn up to 100 km away from the foot of the AP. When föhn winds occur in spring they increase surface melt, extend the melt season and increase the number of melt days within a year. Whilst AMPS is able to simulate the percentage of melt days associated with föhn with high skill, it overestimates the total amount of melting during föhn events and non-föhn events. This study extends previous attempts to quantify the impact of föhn on the Larsen C Ice Shelf by including a 4-year study period and a wider area of interest and provides evidence for föhn-related melting on both the Larsen C and Larsen B ice shelves.

Sign in / Sign up

Export Citation Format

Share Document