Combined analysis of energy and water balances to estimate latent heat flux of a sudanian small catchment

Guyot, Adrien, Cohard, Jean-Martial, Anquetin, Sandrine, Galle, Sylvie and Lloyd, Colin R. (2009) Combined analysis of energy and water balances to estimate latent heat flux of a sudanian small catchment. Journal of Hydrology, 375 1-2: 227-240. doi:10.1016/j.jhydrol.2008.12.027


Author Guyot, Adrien
Cohard, Jean-Martial
Anquetin, Sandrine
Galle, Sylvie
Lloyd, Colin R.
Title Combined analysis of energy and water balances to estimate latent heat flux of a sudanian small catchment
Journal name Journal of Hydrology   Check publisher's open access policy
ISSN 0022-1694
Publication date 2009-08-30
Sub-type Article (original research)
DOI 10.1016/j.jhydrol.2008.12.027
Volume 375
Issue 1-2
Start page 227
End page 240
Total pages 14
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Formatted abstract
Actual evapotranspiration is one of the major components of both energy and water budgets, but is often difficult to monitor over long period with sufficient accuracy. Within the framework of the “AMMA-CATCH” program, a project dedicated to the study of the West African Monsoon, a large aperture scintillometer has been installed in a small catchment (12 km2), located in the North of Benin, a region exposed to sudanian climate. The present study is an attempt to estimate the latent heat flux over this small but heterogeneous catchment based on scintillation and ground observations. The analysis covers the end of the dry season (lasting from February to April 2006). During this period two isolated rainfall events occurred, giving a unique opportunity to study energy and water budgets simultaneously.

The comparison between the average sensible heat flux derived from scintillometer observations and the one obtained with conventional eddy correlation shows a relatively good agreement, where the scattering is mainly explained by differences in footprint associated with both instruments. A relevant hourly residual latent heat flux is then obtained through the energy balance equation, with careful attention brought to the net radiation, and the ground heat fluxes. The residual of the energy budget equation is compared to soil water losses from vadose zone and water table, in order to evaluate whether this estimation is consistent with the water budget of the ground. Daily soil water depletion within the first meter of the surface shows a similar dynamic as the one calculated from the energy balance equation, but exhibits a constant 1 mm/day lag. The excess of actual evapotranspiration is supposed to be explained by water table losses and root extraction by trees. Finally, this study shows how combined energy and water budget analysis can help to better understand water transfers at the watershed scale.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Civil Engineering Publications
 
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Created: Thu, 29 May 2014, 22:27:58 EST by Adrien Guyot on behalf of School of Civil Engineering