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| DOI: | 10.1016/j.agwat.2005.06.001 |
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| Web URL(s): | http://www.sciencedirect.com/science/article/pii/S0378377405002805
Last checked: 01/31/2014
Access conditions: Item is within a limited-access website |
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| Publication Type:
| Refereed |
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| Author(s): | Pauwels, Valentijn R. N.;
Samson, Roeland |
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| Author Affiliation: | Pauwels: Laboratory of Hydrology and Water Management; Samson: Laboratory of Plant Ecology, Ghent University, Ghent, Belgium |
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| Title: | Comparison of different methods to measure and model actual evapotranspiration rates for a wet sloping grassland |
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| Source: | Agricultural Water Management. Vol. 82, No. 1/2, April 10 2006, p. 1-24. |
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| Publishing Information: | [Amsterdam]: Elsevier Scientific Pub. |
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| # of Pages: | 24 |
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| Keywords: | TIC Keywords: Evapotranspiration; Evapotranspiration rate; Slope; Latent heat; Slope surface; Energy balance; Energy exchange; Correlation; Moisture; Testing; Topography; Resistance
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| Abstract/Contents: | "Accurate maesurements of the turbulent exchanges of mass and energy at the land surface are necessary for a good understanding of the various components of the hydrological cycle. The two most commonly used methods to measure evapotranspiration rates are the Bowen ratio energy balance (BREB) and the Eddy correlation (EC) methods. These methods are applicable when a number of requirements, mostly with respect to terrain topography and homogeneous fetch extension, are fulfilled. On the other hand, meterological variables can be used to calculate evapotranspiration rates. The two most frequently used methods for this purpose are the Penman-Monteith (PM) combination equation and the Priestly-Taylor (PT) apporximation. The objective of this paper is to compare these different methods under non-ideal conditions, more specifically for a wet sloping grassland. The BREB-based and EC-based latent heat fluxes are intercompared, and a good agreement between the estimates from both methods is found. A comparison between the results of the PM and PT methods are the measured latent heat fluxes is then done. A strong annual cycle is the calculated values for the PT alfa factor (Α), with a mean annual average value of 1.21 ^D+-0.79, has been observed. This annual cycle is related to the annual cycle of the humidity of the soil, which can be evaluated by either the soil moisture or the vapor deficit of the air. A strong annual cycle in the inverted surface resistances has also been observed. A relationship between inverted surface resistance and Α has been found, in which the highest values for Α coincide with low surface resistance, and vice versa. The results indicate that the methods to measure and calculate latent heat fluxes are in a good agreement, and that imposing an annual cycle in the surface resistance and Α leads to an improvement in the estimated evapotranspiration rates. The results suggest that it is possible to measure or model evapotranspiration rates in situations where the theoretical requirements (more specifically a non-sloping surface) are met." |
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| Language: | English |
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| References: | 31 |
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| Note: | Figures
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Pauwels, V. R. N., and R. Samson. 2006. Comparison of different methods to measure and model actual evapotranspiration rates for a wet sloping grassland. Agric. Water Manage. 82(1/2):p. 1-24. |
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| DOI: 10.1016/j.agwat.2005.06.001 |
| Web URL(s):
http://www.sciencedirect.com/science/article/pii/S0378377405002805
Last checked: 01/31/2014
Access conditions: Item is within a limited-access website |
| 
MSU catalog number: b2205878a |
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