Components of the energy balance of the ground surface and their effect on the thermics of the substrata of the vegetation oasis at Henryk Arctowski Station, King George Island, South Shetland Islands

Polar Record ◽  
2000 ◽  
Vol 36 (196) ◽  
pp. 3-18 ◽  
Author(s):  
P. Prosek ◽  
M. Janouch ◽  
K. Láska
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Soil Temperature ◽  
Sensible Heat Flux ◽  
Ground Surface ◽  
South Shetland Islands ◽  
Radiation Balance ◽  
Sensible Heat ◽  
King George Island ◽  
Shetland Islands

AbstractThis article presents the results of measurements of the components of ground-surface energy balance (radiation balance, sensible heat flux, latent heat flux, and ground heat flux) taken during the 1994/95 summer season at Poland's Henryk Arctowski Station, King George Island, South Shetland Islands (62°09'42”S, 58°28'10”W). This was the first time that these complex measurements had been taken in the central part of the South Shetlands archipelago. The results are evaluated at the level of daily and seasonal fluctuations. The consequences of energy balance on the temperature conditions of the soil substrata are highlighted. The verification of the degree of influence of a subset of energy-balance components on soil temperature allowed analysis of the relationships among soil temperature, radiation balance, and sensible heat flux. This analysis leads to the conclusion that there is a rapid reaction of the soil temperature to the radiation balance and sensible heat flux to a depth of 5 cm. The boundary atmosphere and soil substrate represent the basic components of the ecotops of the Antarctic vegetation oasis, so these results are interpreted in pedological or botanical studies in the search for environmental influences on the vegetation.

scholarly journals Energy Balance Calculations for the Ablation Period 1982 at Vernagtferner. Oetztal Alps

1985 ◽  
Vol 6 ◽  
pp. 158-160 ◽  
Author(s):  
Heidi Escher-Vetter
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Longwave Radiation ◽  
Radiation Balance ◽  
Sensible Heat ◽  
The Individual ◽  
The Relationship ◽  
Climatic Pattern

In this paper, some features of energy balance terms will be discussed in respect to the melting capacity available at the surface of Vernagtferner in the Oetztal Alps. The climatic pattern of summer 1982 is described, then the method of calculating individual terms (shortwave and longwave radiation balance, sensible and latent heat flux) from records of radiation, air temperature, humidity and wind. The results of these calculations are discussed for ice, firn and snow areas of the glacier. In particular the relationship between the four terms is shown for 15 July 1982, the day with highest meltwater production in 1982. These values are then compared with the maximum values of the individual terms, showing that the highest meltwater production is caused by the combination of quite high values of the individual terms, but not of the absolutely highest ones. The importance of sensible heat flux for meltwater production in 1982 is discussed: comparison between meltwater production for the whole summer and measured runoff shows reasonable accordance.

scholarly journals Energy Balance Calculations for the Ablation Period 1982 at Vernagtferner. Oetztal Alps

1985 ◽  
Vol 6 ◽  
pp. 158-160 ◽  
Author(s):  
Heidi Escher-Vetter
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Longwave Radiation ◽  
Radiation Balance ◽  
Sensible Heat ◽  
The Individual ◽  
The Relationship ◽  
Climatic Pattern

In this paper, some features of energy balance terms will be discussed in respect to the melting capacity available at the surface of Vernagtferner in the Oetztal Alps. The climatic pattern of summer 1982 is described, then the method of calculating individual terms (shortwave and longwave radiation balance, sensible and latent heat flux) from records of radiation, air temperature, humidity and wind. The results of these calculations are discussed for ice, firn and snow areas of the glacier. In particular the relationship between the four terms is shown for 15 July 1982, the day with highest meltwater production in 1982. These values are then compared with the maximum values of the individual terms, showing that the highest meltwater production is caused by the combination of quite high values of the individual terms, but not of the absolutely highest ones. The importance of sensible heat flux for meltwater production in 1982 is discussed: comparison between meltwater production for the whole summer and measured runoff shows reasonable accordance.

scholarly journals Response of the Energy Balance on the Margin of the Greenland Ice Sheet to Temperature Changes

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Temperature Response ◽  
Greenland Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.

scholarly journals The impact of broadleaved woodland on water resources in lowland UK: II. Evaporation estimates from sensible heat flux measurements over beech woodland and grass on chalk sites in Hampshire

2005 ◽  
Vol 9 (6) ◽  
pp. 607-613 ◽  
Author(s):  
J. Roberts ◽  
P. Rosier ◽  
D. M. Smith
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Excellent Agreement ◽  
Sensible Heat Flux ◽  
Late Summer ◽  
Eddy Correlation ◽  
Sensible Heat ◽  
Flux Measurements ◽  
Shallow Soils ◽  
The Impact

Abstract. The impact on recharge to the Chalk aquifer of substitution of broadleaved woodland for pasture is a matter of concern in the UK. Hence, measurements of energy balance components were made above beech woodland and above pasture, both growing on shallow soils over chalk in Hampshire. Latent heat flux (evaporation) was calculated as the residual from these measurements of energy balances in which sensible heat flux was measured with an eddy correlation instrument that determined fast response vertical wind speeds and associated temperature changes. Assessment of wind turbulence statistics confirmed that the eddy correlation device performed satisfactorily in both wet and dry conditions. There was excellent agreement between forest transpiration measurements made by eddy correlation and stand level tree transpiration measured with sap flow devices. Over the period of the measurements, from March 1999 to late summer 2000, changes in soil water content were small and grassland evaporation and transpiration estimated from energy balance-eddy flux measurements were in excellent agreement with Penman estimates of potential evaporation. Over the 18-month measurement period, the cumulative difference between broadleaved woodland and grassland was small but evaporation from the grassland was 3% higher than that from the woodland. In the springs of 1999 and 2000, evaporation from the grassland was greater than that from the woodland. However, following leaf emergence in the woodland, the difference in cumulative evaporation diminished until the following spring.

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

2014 ◽  
Vol 8 (1) ◽  
pp. 125-135 ◽  
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.

scholarly journals Diurnal Energy Balance in a Mango Orchard in the Northeast of Pará, Brazil

2018 ◽  
Vol 33 (3) ◽  
pp. 537-546 ◽  
Author(s):  
Paulo Jorge de Oliveira Ponte de Souza ◽  
Juliana Chagas Rodrigues ◽  
Adriano Marlisom Leão de Sousa ◽  
Everaldo Barreiros de Souza
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Soil Cover ◽  
Sensible Heat Flux ◽  
Sensible Heat ◽  
Net Radiation ◽  
Growing Seasons ◽  
Available Energy

Abstract This study aimed to evaluate the diurnal energy balance during the reproductive stage of two growing seasons of a mango orchard in the northeast of Pará, Brazil. Therefore, a micrometeorological tower was installed and instrumented, in the center of the experimental area, to monitor meteorological variables, besides the phenological evaluation of the mango orchard, which was carried out during growing seasons of 2010-2011 (October 2010 to January 2011) and of 2011-2012 (September 2011 to January 2012). The energy balance was obtained by the bowen ration technique, and the available energy partitioned into heat flux to the ground, sensible heat and latent heat. The amount of rainfall was crucial to the partition of the net radiation in the energy balance components. It provided the variation in the consumption of available energy between 69% and 78% as latent heat flux, and between 23% and 32% as sensible heat flux. The heat flux to the ground was small, representing less than 1% of the net radiation, showing that the mango orchard exhibits good soil cover preventing large variations in soil heating.

scholarly journals Response of the Energy Balance on the Margin of the Greenland Ice Sheet to Temperature Changes

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Temperature Response ◽  
Greenland Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.

Comparison of energy fluxes from eddy covariance and scintillometer over an agricultural field

2020 ◽  
Author(s):  
Matěj Orság ◽  
Milan Fischer ◽  
Josef Eitzinger ◽  
Miroslav Trnka
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Eddy Covariance ◽  
Latent Heat ◽  
Soil Heat Flux ◽  
Radiation Balance ◽  
Energy Balance Closure ◽  
Sensible Heat ◽  
Agricultural Field ◽  
Available Energy

<p>In this study we compare turbulent energy fluxes obtained from eddy covariance (EC) (LI-7500A, LI-COR + Windmaster, Gill Instruments) and large aperture scintillometer (BLS900, Scintec) over an agricultural field (wheat field, straw and bare soil). As the EC method provides direct measurements of sensible heat (H<sub>EC</sub>) and latent heat (LE<sub>EC</sub>) fluxes we use it as a reference method. The EC method enables to determine fluxes within a footprint centered around the point of measurement in the middle of the field. The scintillometer provides an estimation of sensible heat flux (H<sub>SC</sub>), derived from air refractive index fluctuation integrated over the measurement path length, in this case 570 m diagonally across whole field. The reference measurements of the radiation balance components consist of 4-component net radiometer for net radiation (Rn) (NR01, Hukseflux), three soil heat flux plates for soil heat flux (G) monitoring (HFP01, Hukseflux), including thermocouples for quantification of the heat storage above the soil heat flux plates. The scintillometer-based latent heat (LE<sub>SC</sub>) is calculated as a residuum from available energy (Rn-G) and H<sub>SC</sub>, provided by scintillometer. The measurement of radiation balance components was located at the top of 3.5 m mast with the EC system, while the soil heat flux plates were collocated around in 5 cm depth. The site is a flat, rectangular agricultural field (app. 16.5 ha), in the north-eastern Austria, Danube river lowland (48.21N, 16.622E), sown with winter wheat during growing season 2019. The measurement campaign was established in February 2019 with aim for multi-seasonal monitoring. The EC measurement height is 2.7 m, the scintillometer transmitter and receiver are fixed on 4 m masts, facing towards each other from NW and SE corners of the field.</p><p>Comparison of the EC-based turbulent fluxes (H<sub>EC</sub>+LE<sub>EC</sub>) and the available energy (Rn-G) during the period March to Mid-June showed a very good agreement, resulting in the energy balance closure of 0.96 (R<sup>2 </sup>= 0.93). This suggest high accuracy and robustness of the measurement setup together with the ability of the EC method to capture all scales of eddies responsible for energy transport at this site. The comparison of methods indicates that H<sub>SC</sub> overestimated H<sub>EC</sub> by 10 % (R<sup>2 </sup>= 0.74) and LE<sub>SC</sub> underestimated LE<sub>EC</sub> by 13 % (R<sup>2 </sup>= 0.81). Related to Rn, the H<sub>EC</sub>, LE<sub>EC</sub> and G fluxes accounted for 22 % (R<sup>2 </sup>= 0.53), 59 % (R<sup>2 </sup>= 0.70) and 15% (R<sup>2 </sup>= 0.62) of the Rn flux, respectively. We assume that the combination of EC and scintillometer method has a potential to bring deeper insight into the analysis of the energy balance closure problem.</p>

scholarly journals Evaluation of a Two-Source Snow–Vegetation Energy Balance Model for Estimating Surface Energy Fluxes in a Rangeland Ecosystem

2014 ◽  
Vol 15 (1) ◽  
pp. 143-158 ◽  
Author(s):  
Cezar Kongoli ◽  
William P. Kustas ◽  
Martha C. Anderson ◽  
John M. Norman ◽  
Joseph G. Alfieri ◽  
...  
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Surface Energy ◽  
Snow Cover ◽  
Sensible Heat Flux ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat ◽  
Energy Fluxes ◽  
Surface Energy Fluxes

Abstract The utility of a snow–vegetation energy balance model for estimating surface energy fluxes is evaluated with field measurements at two sites in a rangeland ecosystem in southwestern Idaho during the winter of 2007: one site dominated by aspen vegetation and the other by sagebrush. Model parameterizations are adopted from the two-source energy balance (TSEB) modeling scheme, which estimates fluxes from the vegetation and surface substrate separately using remotely sensed measurements of land surface temperature. Modifications include development of routines to account for surface snowmelt energy flux and snow masking of vegetation. Comparisons between modeled and measured surface energy fluxes of net radiation and turbulent heat showed reasonable agreement when considering measurement uncertainties in snow environments and the simplified algorithm used for the snow surface heat flux, particularly on a daily basis. There was generally better performance over the aspen field site, likely due to more reliable input data of snow depth/snow cover. The model was robust in capturing the evolution of surface energy fluxes during melt periods. The model behavior was also consistent with previous studies that indicate the occurrence of upward sensible heat fluxes during daytime owing to solar heating of vegetation limbs and branches, which often exceeds the downward sensible heat flux driving the snowmelt. However, model simulations over aspen trees showed that the upward sensible heat flux could be reversed for a lower canopy fraction owing to the dominance of downward sensible heat flux over snow. This indicates that reliable vegetation or snow cover fraction inputs to the model are needed for estimating fluxes over snow-covered landscapes.

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

2014 ◽  
Vol 15 (3) ◽  
pp. 1078-1090 ◽  
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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