Agricultural and Forest Meteorology 191 (2014) 64–80 Contentslists availableat ScienceDirect Agricultural and Forest Meteorology j o u r n a l h o me p a g e : w w w . e l s e v i e r . c o m / l o c a t e / a g r f o r m e t A three-sourceSVAT modeling of evaporation: Application to the seasonal dynamics of a grassed vineyard Carlo Montes a,∗ , Jean-Paul Lhomme a , Jérôme Demarty b , Laurent Prévot c , Frédéric Jacob a a InstitutdeRecherche pour le Développement, UMR LISAH, 34060Montpellier, France b InstitutdeRecherche pour le Développement, UMR HSM, 34095Montpellier, France c InstitutNational dela Recherche Agronomique, UMR LISAH, 34060Montpellier, France a r t i c l e i n f o Articlehistory: Received12 June 2013 Receivedin revisedform 5 February2014 Accepted13 February2014 Available online 15 March 2014 Keywords: Latent heat flux Multi-source Sparsevegetation Soil water balance Seasonal course a b s t r a c t A parsimoniousand versatileSoil–Vegetation–Atmosphere Transfer(SVAT) model is proposedfor three component vineyards, which includes vine foliage, grassed soil and bare soil. A three-source energy balance approach describes the energy and mass transfer between the soil–plant continuum and the lower atmospherewith an hourly time step. It is coupled with a soil water balance module running with a daily time step. The model makes use of standard meteorological data together with parame- ters describing foliage development,grass and soil characteristics. The model is calibrated by means of the Multi-objective Calibration Iterative Process (MCIP) algorithm and next validated for evapora- tion and soil moisture over a dataset collected in a Southern France grassedvineyard. The validation exerciseis twofold. It focuses first on the daily course of evaporationderived from the surfaceenergy balancemodule only, forcedwith meteorological variables, net radiationand soil moisture.The compari- son againstEddy Covariance measurements shows a good agreement (R 2 =0.96and RMSE=14.0W m −2 ). Next,a simulation coupling the surfaceenergybalancemodule with the soil water balancemodule is val- idated over Eddy Covariance and soil moisture measurements. Simulations throughout two contrasting growing seasonsprovide good estimatesof daily evaporation(R 2 =0.90 and RMSE=0.43mm d −1 ) and soil water content (R 2 =0.98 and RMSE =6.95mm). Model inaccuracies arise mainly under conditions of strong surfacerunoff. Results also suggestthat the parameterizations relating the surface-atmosphere module with the soil module (i.e. stomatal resistance) should be carefully examinedunder water stress conditions. Finally, the model versatility is addressedthrough a set of simulations. It appearsthat the modeling approach allows assessingthe seasonal water balanceof vineyards with different structure (grassfraction or distancebetween rows) and that it could be applied to similar cropping systems. ©2014 ElsevierB.V. All rights reserved. 1. Introduction Progress in theoretical and applied research aiming at accu- rately assessing crop water consumption in both rain-fed and irrigated conditions is an essential issue for agricultural water management. Since evaporation measurementsare scarce, oper- ational formulations to estimate water consumption at field scale are necessary (Trambouze et al., 1998; Spano et al., 2009). For viticulture regions in Mediterranean and semi-arid environments, actual evaporationrepresentsa major component of surfacewater balance, reaching up to 70%of the yearly precipitation (Moussa ∗ Correspondingauthor at: UMR LISAH, 2 place Pierre Viala, 34060 Montpellier, France.Tel.: +3307 85 40 83 26. E-mail address: ccmontesv@gmail.com (C. Montes). et al., 2007). Knowledge of actual evaporation is also of interest in viticulture, in order to assessand handle the influence of soil water deficit on grapevineyields and berry composition (Vaudour, 2003; Pellegrino et al., 2005). Nevertheless, the physical repre- sentation of the soil–plant–atmosphere system in grapevinesis a complex issue, becausethe sparse structure of vineyards imposes to consider both the foliage and the understory, which requires multi-source modeling. The most frequently used multi-source evaporation model is the one first developedby Shuttleworth and Wallace (1985) (S–W model) and extended by Choudhury and Monteith (1988) and Shuttleworth and Gurney (1990). This model corresponds to an extension of the big-leaf model of Penman–Monteith (Monteith, 1965) into two interacting evaporative layers: the main foliage and the underlying substrate.Subsequently, the S–W model was upgraded by Brenner and Incoll (1997) (“clumped” model) to http://dx.doi.org/10.1016/j.agrformet.2014.02.004 0168-1923/©2014 Elsevier B.V. All rights reserved.