scholarly journals Comparison of methods for estimating evapotranspiration rate of dry forest canopy: Eddy covariance, Bowen ratio energy balance, and Penman-Monteith equation

2008 ◽  
Vol 113 (D19) ◽  
Author(s):  
Ting-Ting Shi ◽  
De-Xin Guan ◽  
Jia-Bing Wu ◽  
An-Zhi Wang ◽  
Chang-Jie Jin ◽  
...  
Keyword(s):  
Energy Balance ◽  
Eddy Covariance ◽  
Forest Canopy ◽  
Bowen Ratio ◽  
Dry Forest ◽  
Comparison Of Methods ◽  
Evapotranspiration Rate ◽  
Monteith Equation ◽  
Ratio Energy

An evaluation of the water balance technique for the estimation of evapotranspiration for a mixed forest

1991 ◽  
Vol 21 (11) ◽  
pp. 1622-1631 ◽  
Author(s):  
T. N. Papakyriakou ◽  
J. H. McCaughey
Keyword(s):  
Energy Balance ◽  
Water Balance ◽  
Mixed Forest ◽  
Bowen Ratio ◽  
Integration Period ◽  
Evapotranspiration Rate ◽  
Minimum Number ◽  
Balance Technique ◽  
Time Required ◽  
Ratio Energy

In the summer of 1987 a detailed field experiment was conducted at the Petawawa National Forestry Institute at Chalk River, Ontario, to evaluate the performance of the water balance technique for the estimation of evapotranspiration. Bowen ratio – energy balance estimates of evapotranspiration, available over a portion of an intensive measurement period, provided an independent check on the water balance estimates. The daily totals of evapotranspiration were on average 1% less than the Bowen ratio – energy balance estimate. The length of time required to maintain the evapotranspiration estimates below a 10% level of uncertainty using the water balance technique is 13 days. The lowest average daily percent probable error is obtained for an integration period with (i) a minimum number of precipitation events, (ii) a large number of days, and (iii) a high evapotranspiration rate.

scholarly journals Micrometeorological methods to estimate sugarcane evapotranspiration in coastal northeastern region of Brazil

2019 ◽  
pp. 1422-1428
Author(s):  
Adolpho Emanuel Quintela da Rocha ◽  
José Leonaldo de Souza ◽  
Guilherme Bastos Lyra ◽  
Ricardo Araújo Ferreira Junior ◽  
Gustavo Bastos Lyra ◽  
...  
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Eddy Covariance ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Bowen Ratio ◽  
Water Vapour Pressure ◽  
Sensible Heat ◽  
Energy Balance Method ◽  
Ratio Energy

The aim of the present work was to evaluate the performance of Bowen ratio-energy balance method, as well as the energy balance closure by Eddy covariance technique for a sugarcane crop in Brazilian northeastern region. Micrometeorological measurements were carried out between June 7th and November 17th, 2013. Latent and sensible heat fluxes were determined through Eddy covariance technique (EC) and by the Bowen ratio-energy balance method (BREB), considering two approaches. The first, estimated the air temperature and water vapour pressure gradient in two levels above the canopy. The second method measured the air temperature and water vapour pressure at the first level and the surface temperature from radiometric measurements. Latent heat flux was also estimated as energy balance residue from determinations of the sensible heat flux by Eddy covariance. The degree of energy balance closure was dependent on the time of the day considered. Bowen ratio - energy balance estimated from the first approach, showed the best agreement with the eddy covariance measurements to estimate latent heat flux, while in the second case, when the Bowen ratio was estimated using the surface temperature, the linear relationship was the most discrepant. Therefore, the Bowen ratio conventional method is more suitable for estimating latent heat flux in sugarcane.

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 Bower ratio-energy balance associated errors in vineyards under dripping irrigation

2007 ◽  
Vol 22 (2) ◽  
pp. 233-240 ◽  
Author(s):  
José Monteiro Soares ◽  
Pedro Vieira De Azevedo ◽  
Bernado Barbosa Da Silva
Keyword(s):  
Energy Balance ◽  
Soil Surface ◽  
Field Measurements ◽  
Bowen Ratio ◽  
Global Solar Radiation ◽  
Soil Heat Flux ◽  
Vitis Vinifera L ◽  
Data Logger ◽  
And Storage ◽  
Ratio Energy

This study was conducted at the Bebedouro Experimental Station in Petrolina-PE, Brazil, to evaluate the errors associated to the application of the Bowen ratio-energy balance in a 3-years old vineyard (Vitis vinifera, L), grown in a trellis system, irrigated by dripping. The field measurements were taken during fruiting cycle (July to November, 2001), which was divided into eigth phenological stages. A micrometeorological tower was mounted in a grape-plants row in which sensors of net radiation, global solar radiation and wind speed were installed at about 1.0 m above the canopy. Also in the tower, two psicometers were installed at two levels (0.5 and 1.8 m) above the vineyard canopy. Two soil heat flux plates were buried at 0.02 m beneath the soil surface. All these sensors were connected to a Data logger 21 X of Campbell Scientific Inc., programmed for collecting data once every 5 seconds and storage averages for every 15 minutes. A comparative analysis were made among four Bowen ratio accepting/rejecting rules, according to the methodology proposed by Spano et al. (2000): betar1 - values of beta calculated by Bowen (1926) equation; betar2 - values of beta as proposed by Verma et al. (1978) equation; betar3 - exclusion of the beta values obtained as recommended by Unland et al. (1996) and betar4 - exclusion of the beta values calculated as proposed by Bowen (1926), out of the interval (-0.7 < beta < 0.7). Constacted that the Unland et al. (1996) and Soares (2003) accepting/rejection rules were better than that of Verma et al. (1978) for attenuating the advective effects on the calculations of the Bowen ratio. The comparison of betar1 with betar2 rules showed that the statistical errors reaching maximum values of 0.015. When comparing betar1 with betar3 e betar4, the beta errors reaching maximum values of 5.80 and 3.15, respectively.

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