Davide Canone

Estimation of Surface Characteristics Using GNSS LH-Reflected Signals: Land Versus Water

Estimating the characteristics of soil surface represents a significant area in applications such as hydrology, climatology, and agriculture. Signals transmitted from Global Navigation Satellite Systems (GNSSs) can be used for soil monitoring after reflection from the Earths surface. In this paper, the feasibility of obtaining surface characteristics from the power ratio of left-hand (LH) reflected signal-to-noise ratio (SNR) over direct right-hand (RH) is investigated. The analysis was done regardless of the surface roughness and the incoherent components of the reflected power. First, the analysis was carried out on data collected during several in situ measurements in controlled environments with known characteristics. Then, further data were collected by a GNSS receiver prototype installed on a small aircraft and analyzed. This system was calibrated on the basis of signals reflected from water. The reflectivity and the estimated permittivity showed good correlation with the types of underlying terrain.

Evaluation of Stemflow Effects on the Spatial Distribution of Soil Moisture Using TDR Monitoring and an Infiltration Model

AbstractThe partitioning of crop canopy water may affect soil water distribution and this may in turn affect sprinkler irrigation application efficiency. The aim of this work was to develop a methodology to evaluate spatial and temporal soil water content distribution in the case of sprinkler irrigation application efficiency considering stemflow. Time domain reflectometry (TDR) soil moisture monitoring was carried out on eight soil water sensor locations for both center pivot and traveling big gun irrigation in different phenological and tillage cases. The two case studies were chosen because they show the two opposite limits of the methodology’s application. Two water distribution estimation methods were employed: raw measured soil moisture and model simulation of the infiltration process. The infiltration process was modeled by means of the two-dimensional (2D) Richard’s equation. The simulations were calibrated on the data measured at eight soil water sensor locations. The stemflow and surface runoff ...

The Finite Volume Formulation for 2D Second-Order EllipticProblems with Discontinuous Diffusion/Dispersion Coefficients

We propose a finite volume method for the numerical resolution of two-dimensional steady diffusion problems with possibly discontinuous coefficients on unstructured polygonal meshes. Our numerical method is cellcentered, secondorder accurate on smooth solutions and based on a special numerical treatment of the diffusion/dispersion coefficients that makes its application possible also when such coefficients are discontinuous. Numerical experiments confirm the convergence of the numerical approximation and show a good behavior on a set of benchmark problems in two space dimensions.