5 research outputs found
Time-dependent sensitivity and uncertainty analyses of an agro-climatic model for the water status management of vineyard
International audienceThis work describes the global sensitivity analysis (SA) of an agro-climatic model embedded in a decision support system (DSS) for the water status management of vineyard in the Languedoc-Roussillon region, France
Comparison of two modeling approaches for water transfer in the soil-vegetation-atmosphere continuum
As part of a R&D project aiming at providing vineyard managers with a computer-based decision support system for optimizing irrigation, we discuss the validity of two modeling approaches for water transfers in the soil-plant-atmosphere continuum. The two models are an empirical âbucketlikeâ model and a mechanistic model based on the 1D Richardsâ equation. The practical context implying that soil-water parameters are poorly estimated, both models are compared in terms of accuracy and parameterization cost. The models are coupled to the same canopy growth, radiation absorption, evaporation and transpiration models, and the predawn leaf water potential (PLWP) is used as the indicator of soil-water deficit. The parameters of both models are estimated with pedotransfer functions from the single texture and the only additional input for the 1D model is root repartition versus depth. A multi-factor sensitivity analysis relative to the input parameters of the soil-vegetation-atmosphere coupling shows that the hard-to-obtain rooting depth is the key factor of the PLWP sensitivity. It also shows that the computation of PLWP with the 1D model is robust against root distribution uncertainty, so that root distribution can be fixed to a mean value. The accuracy of the two models is evaluated in vineyards varying in soil type, rooting depth and irrigation procedure in the Languedoc region (France), by comparing simulated to measured values of vine transpiration and PLWP. Provided the calibration of rooting depth, both models give results coherent with field measurements, with no significant improvement when the more physical mechanistic model is used
A model-driven decision support system for vineyard water status management: a time-dependent sensitivity analysis
International audienceThe global sensitivity analysis of a dynamic soil water balance model embedded in a Decision Support System for vineyard water management is achieved via the Sobol variance-based method. The sensitivity analysis is applied sequentially at each simulation step so that the variation of parameter influence over time can be followed. Results allow identification of four soil-related parameters having the highest influence at the vine plot scale, and for various climate scenarios. This provides fundamental information for the operational use of the model, i.e. when few input data are available to the end-user