scholarly journals Energy and Water Balances of a Bog in Central Sweden

1997 ◽  
Vol 28 (4-5) ◽  
pp. 263-272 ◽  
Author(s):  
Mattias Phersson ◽  
Ola Pettersson
Keyword(s):  
Energy Balance ◽  
Groundwater Level ◽  
Evaporation Rate ◽  
Bowen Ratio ◽  
Groundwater Table ◽  
Ratio Method ◽  
Considerable Part ◽  
Balance Study ◽  
Energy Balances ◽  
Low Precipitation

Fens and bogs represent a considerable part of the boreal forest area of Scandinavia, but have not received much attention. To understand their role in the water and energy balances an investigation was carried out during the spring and summer of 1994 as a part of the NOPEX program. Groundwater level, precipitation and energy budget parameters were measured at the Ryggmossen bog, 35 km Northwest of Uppsala. The evaporation (10 min averages) was determined by the Energy Balance Bowen Ratio method and a reference evaporation (10 min averages) was also calculated according to Penman (1948). The results of the evaporation and energy balance study showed that the actual evaporation was 60% of the reference evaporation and that the evaporation rate was dependent on the groundwater depth. The weather during the period was warm with extremely low precipitation. The evaporation therefore decreased during the summer in response to the increased depth to the groundwater table. A relation was found between the groundwater level recession rate and the evaporation rate. The albedo increased during the summer and any occasional decrease could be attributed to individual rain storms.

scholarly journals Avaliação da Evapotranspiração de Pastagem pelo Método do Domo (Evaluation of Grassland Evapotranspiration by Dome Method)

2014 ◽  
Vol 7 (4) ◽  
pp. 716
Author(s):  
Irami Buarque Amazonas ◽  
Antônio Celso Dantas Antonino ◽  
Willames Albuquerque Sores ◽  
José Romualdo Sousa Lima ◽  
Suzana Maria Gico Lima Montenegro
Keyword(s):  
Experimental Data ◽  
Energy Balance ◽  
Bowen Ratio ◽  
Botanical Garden ◽  
Ratio Method ◽  
Satisfactory Performance ◽  
De Se ◽  
Para Determinar ◽  
The Town ◽  
Semi Arid

A região semiárida nordestina necessita de formas alternativas confiáveis economicamente e viáveis de se estimar a evaporação (E) ou a evapotranspiração (ET), uma vez que apresenta um regime de chuvas irregular e a ET se constitui na principal perda de água no sistema solo-planta-atmosfera. Dentre os vários métodos de se determinar a ET, o domo tem sido comparado com outros métodos, apresentando desempenho satisfatório e, por ser mais barato do que os demais, pode se tornar uma alternativa viável para medidas rápidas e pontuais. O domo consiste em uma cúpula de acrílico colocada sobre o solo, onde se determina a E ou ET a partir de medidas de temperatura e umidade no seu interior. Neste trabalho o domo foi usado para determinar a ET de uma pastagem, no município de São João-PE, e os resultados foram confrontados com os obtidos pelo balanço de energia-razão de Bowen. Verificou-se que o método do domo apresentou resultados satisfatórios na determinação da ET, sendo a média diária de 3,33 e 4,05 mm d-1, obtidas pelo domo e pela razão de Bowen, respectivamente. A metodologia do domo possui a desvantagem de não ser automatizada e subestimar a ET nos horários de maior incidência de radiação.    A B S T R A C T The semi-arid northeastern need of alternative reliable and economically feasible to estimate evaporation (E) or evapotranspiration (ET), since it presents an irregular rainfall and ET constitutes the main loss of water in the soil-plant-atmosphere. Among the various methods of determining the ET, the dome has been compared with other methods, showing satisfactory performance, and because it is cheaper than the others, it can become a viable alternative for rapid and punctual measures. The dome consists of an acrylic dome placed over the soil, where it determines the E or ET from measurements of temperature and humidity inside. In this work, the dome was used to determine the ET of grassland in the town of São João, in the Pernambuco state, and the results were compared with experimental data obtained from the energy balance-Bowen ratio method. It has been found that the method of the dome was satisfactory in determining ET of the grassland and the average daily ET was 3.33 and 4.05 mmd-1, obtained by the dome and by Bowen ratio, respectively. The methodology of the dome has the disadvantage of not being automated and underestimates the evapotranspiration in times of highest incidence of radiation. Keywords: Native fruits, Flora of Brazil, Phenology, Botanical Garden 

scholarly journals A field study on Ground Energy Balance calculation for typical communities in South China

2020 ◽  
Vol 172 ◽  
pp. 25003
Author(s):  
Riyi Li ◽  
Yufeng Zhang ◽  
Chongyun Huang ◽  
Chundian He
Keyword(s):  
Energy Balance ◽  
Solar Radiation ◽  
Latent Heat ◽  
South China ◽  
Convective Heat Transfer Coefficient ◽  
Bowen Ratio ◽  
Ground Temperature ◽  
Ratio Method ◽  
Subtropical Climate ◽  
Ground Energy

Urban heat island (UHI) greatly influences human health, comfort and building energy. The ground temperature plays an important role in understanding UHI, and the method based on the ground energy balance (GEB) is fundamental in the predictions of urban ground temperature and UHI. South China is fast developed and highly urbanized, with special humid subtropical climate and particular urban design characteristics. Although amounts of methods or formulas have been previously proposed for urban GEB calculation, few of them has been testified in field in South China. In this study, two typical urban communities in South China in the aligned and enclosed layout were measured during the summer sunny days in Aug. 2017, with the focus on incident solar radiation, sensible heat, and latent heat of the ground. The measured data were compared with the calculated ones by various methods. The results show that the two calculation methods, i.e., with and without reflections, showed comparable performances (difference on RMSE 3-13 W/m2) in the prediction of solar radiation incident into the community ground. The previously proposed formulas performed poorly in the prediction of surface convective heat transfer coefficient for the community hard pavement, and the power function regressed by using the measuring data performed well, with the air speed at the reference height of 0.13 m as variable and R2 of 0.74. The Bowen ratio method performed better in the prediction of latent heat for the community permeable sidewalk, with RMSE of 156 W/m2 and the consistency index of 0.93. This study provides the field evidences and reliable methods for urban GEB calculation, and potentially contributes to the UHI prediction and mitigation in South China.

scholarly journals Dynamics of the status of groundwater in the Polish Lowland: the River Gwda catchment example

Geologos ◽  
2019 ◽  
Vol 25 (3) ◽  
pp. 193-204
Author(s):  
Izabela Jamorska ◽  
Katarzyna Kubiak-Wójcicka ◽  
Arkadiusz Krawiec
Keyword(s):  
Groundwater Level ◽  
Catchment Area ◽  
Meteorological Parameters ◽  
Groundwater Table ◽  
Annual Precipitation ◽  
Observation Well ◽  
Total Annual Precipitation ◽  
Drainage Zone ◽  
The Status ◽  
Low Precipitation

Abstract The aim of the present study is to monitor changes in the location of the groundwater table in the catchment area of the River Gwda within the Quaternary and Neogene water-bearing level over a 35-year period, between 1981 and 2015. In addition, on account of very diverse total annual precipitation levels in particular parts of the catchment, attempts were made to determine the influence of precipitation on the location of the groundwater table. By correlating groundwater level and meteorological parameters (precipitation), it was discovered that precipitation in the previous year made the largest impact on the groundwater table. Moreover, low precipitation totals in the southern part of the catchment are not discernible in groundwater table fluctuations, which is linked to the location of the observation well within the drainage zone as well as to water ascension from deeper aquifers.

Long-term energy balance measurements at three different mountain permafrost sites in the Swiss Alps

2020 ◽  
Author(s):  
Martin Hoelzle ◽  
Christian Hauck ◽  
Jeannette Noetzli ◽  
Cécile Pellet ◽  
Martin Scherler
Keyword(s):  
Energy Balance ◽  
Air Temperature ◽  
Bowen Ratio ◽  
Heat Fluxes ◽  
Swiss Alps ◽  
Ratio Method ◽  
Fine Grained ◽  
Mountain Permafrost ◽  
Ice Content

<p>The surface energy balance is one of the most important influencing factors for the ground thermal regime. It is therefore crucial to understand the interactions of the individual heat fluxes at the surface and within the subsurface layers as well as their relative impacts. A unique set of high-altitude meteorological measurements has been analysed to determine the energy balance at three mountain permafrost sites in the Swiss Alps, where data is being collected since the late 1990s in collaboration with the Swiss Permafrost Monitoring (PERMOS). The three stations have a standardized equipment with sensors for four-component radiation, air temperature, humidity, wind speed and direction as well as ground temperatures and snow height. The three sites differ considerably by their surface and ground material composition ranging from a coarse blocky active layer above ice supersaturated permafrost at rock glacier Murtèl-Corvatsch to deeply weathered micaceous shales, which are covered by fine grained debris of sandy and silty material with a low ice content at the Northern slope of Schilthorn summit. The third site at the Stockhorn plateau shows intermediate ice contents and heterogeneous surface conditions with medium-size debris, fine grained material and outcropping bedrock. Ice content estimation and general ground characterisation are based on geophysical surveying and borehole drilling.</p><p> </p><p>The energy fluxes are calculated based on around two decades of field measurements. While the determination of the radiation budget and the ground heat flux is comparatively straightforward (by the four-component radiation sensor and thermistor measurements within the boreholes, respectively), larger uncertainties exist for the determination of sensible and latent turbulent heat fluxes. They are therefore determined on the one hand by the bulk aerodynamic method using the bulk Richardson number to describe the stability of the surface layer relating the relative effects of buoyancy to mechanical forces and on the other hand by the bowen ratio method.</p><p> </p><p>Results show that mean air temperature at Murtèl-Corvatsch (1997–2018, elevation 2600 m asl.) is –1.66°C and has increased by about 0.7°C during the observation period. The Schilthorn (1999–2018, elevation 2900 m asl.) site shows a mean air temperature of –2.48°C with a mean increase of 1.0°C and the Stockhorn (2003–2018, elevation 3400 m asl.) site shows lower air temperatures with a mean of –5.99°C with an increase of 0.6°C. Measured net radiation, as the most important energy input at the surface, shows substantial differences with mean values of 33.41 Wm<sup>-2</sup> for Murtèl-Corvatsch, 40.65 Wm<sup>-2</sup> for Schilthorn and 24.88 Wm<sup>-2</sup> for Stockhorn. The calculated turbulent fluxes show values of around 7 to 12 Wm<sup>-2</sup> using the bowen ratio method and 8 to 18 Wm<sup>-2</sup> using the bulk method at all sites. Large differences are observed regarding the energy used for melting of the snow cover: at Schilthorn a value of 12.41 Wm<sup>-2</sup>, at Murtèl-Corvatsch of 7.31 Wm<sup>-2</sup> and at Stockhorn of 3.46 Wm<sup>-2</sup> is calculated reflecting the differences in snow height at the three sites.</p>

Innovative energy and mass balance of a continuous evaporating crystallizer

2019 ◽  
pp. 646-654
Author(s):  
Jan Iciek ◽  
Kornel Hulak ◽  
Radosław Gruska
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Working Conditions ◽  
Crystallization Process ◽  
Heat Losses ◽  
Inert Gas ◽  
Gas Removal ◽  
Energy Balances ◽  
Heat Released ◽  
Mass And Energy Balances

The article presents the mass and energy balances of the sucrose crystallization process in a continuous evaporating crystallizer. The developed algorithm allows to assess the working conditions of the continuous evaporating crystallizers and the technological and energy parameters. The energy balance algorithm takes into account the heat released during the crystallization of sucrose, which was analyzed in this study, heat losses to the environment and heat losses due the vapor used for inert gas removal.

BOWEN RATIO-ENERGY BALANCE ESTIMATES OF EVAPOTRANSPIRATION AND CROP COEFFICIENT FOR TOMATO PLANTS

1996 ◽  
pp. 121-126
Author(s):  
A.M.R. Abdel-Mawgoud ◽  
S.O. El-Abd ◽  
A.F. Abou-Hadid ◽  
T.C. Hsiao
Keyword(s):  
Energy Balance ◽  
Crop Coefficient ◽  
Bowen Ratio ◽  
Tomato Plants ◽  
Ratio Energy

scholarly journals Evaporation from (Blue-)Green Roofs: Assessing the Benefits of a Storage and Capillary Irrigation System Based on Measurements and Modeling

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1253 ◽  
Author(s):  
Dirk Cirkel ◽  
Bernard Voortman ◽  
Thijs van Veen ◽  
Ruud Bartholomeus
Keyword(s):  
Energy Balance ◽  
Urban Areas ◽  
Evaporation Rate ◽  
Climate Adaptation ◽  
Irrigation System ◽  
Green Roof ◽  
Green Roofs ◽  
C3 Plants ◽  
Rapid Decline ◽  
Air Temperatures

Worldwide cities are facing increasing temperatures due to climate change and increasing urban density. Green roofs are promoted as a climate adaptation measure to lower air temperatures and improve comfort in urban areas, especially during intensive dry and warm spells. However, there is much debate on the effectiveness of this measure, because of a lack of fundamental knowledge about evaporation from different green roof systems. In this study, we investigate the water and energy balance of different roof types on a rooftop in Amsterdam, the Netherlands. Based on lysimeter measurements and modeling, we compared the water and energy balance of a conventional green roof with blue-green roofs equipped with a novel storage and capillary irrigation system. The roofs were covered either with Sedum or by grasses and herbs. Our measurements and modeling showed that conventional green roof systems (i.e., a Sedum cover and a few centimeters of substrate) have a low evaporation rate and due to a rapid decline in available moisture, a minor cooling effect. Roofs equipped with a storage and capillary irrigation system showed a remarkably large evaporation rate for Sedum species behaving as C3 plants during hot, dry periods. Covered with grasses and herbs, the evaporation rate was even larger. Precipitation storage and capillary irrigation strongly reduced the number of days with dry-out events. Implementing these systems therefore could lead to better cooling efficiencies in cities.

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