Modélisation directe par différences finies du fonctionnement d’une sonde TDR - Etude de la sensibilité spatiale tridimensionnelle - Fayçal REJIBA, Philippe COSENZA, Christian CAMERLYNCK, Alain TABBAGH UMR 7619 Sisyphe, Université Pierre et Marie Curie, case 105, 4 place. Jussieu, 75252 Paris cedex 05, France Abstract A three-dimensional (3D) transient electromagnetic modeling based on a full-wave formulation (Maxwell’s equations) has been undertaken in order to study the impact of heterogeneities located near a Time Domain Reflectometry (TDR) probe. We focused on 3D eneities located around the ends of rods: (a) interface perpendicular to the probe plane located below the end of rods and (b) 3D (cubic and parallelepipedic) heterogeneities whose characteristic lengths are similar to that of the probe. Whatever the rod separation and whatever the dielectric constant contrasts, an interface located just beneath the end of the rod does not affect significantly a simulated TDR signal when the interface is farther than one-rod diameter. However, all the simulations carried out with cubic and parallelepipedic heterogeneities located along TDR rods have shown that a significant longitudinal sensitivity exists. Introduction L’évaluation de la teneur en eau en proche surface dans les milieux non saturés est actuellement un objectif majeur pour la caractérisation des sols et la compréhension des mécanismes dynamiques liés au transfert ...