Am\'elioration de l'\'etude de l'\'etude de l'humidit\'e de sols par radiom\'etrie. Caract\'erisation et mod\'elisation di\'electriques de profils g\'eologiques

TL;DR

This paper develops a numerical model to simulate geological structures and their dielectric properties to improve soil moisture estimation using radiometry, considering various environmental and soil parameters.

Contribution

It introduces a comprehensive numerical model that accounts for complex geological and environmental factors affecting microwave radiometry measurements.

Findings

Successful simulation of geological structures' dielectric properties.

Enhanced accuracy in soil moisture estimation from radiometric data.

Identification of key parameters influencing microwave emission signals.

Abstract

The surface soil moisture is a key variable to describe the exchange of water and energy between the land and the atmosphere. In hydrology, and meteorology, the amount of water in the upper soil layers permits (0-5 cm from the surface) the evaluation of the relationship between the real evaporation and the potential evaporation of the bare soil. It is also possible to determine the distribution of rainfall or other variables such as hydraulic conductivity. Studies have shown that microwave sensors could be used to scan the surface soil moisture. The solution choose by the team associated with the SMOS mission (Soil Moisture and Ocean Salinity) is to use a radiometer (1.4 GHz) to identify soil microwave emissions . The measurements are made on the site of CESBIO in Toulouse where a 1.4 GHz radiometer is installed . The effect of vegetation cover, soil temperatures, snow cover, topography or moisture variations have an important role in the broadcast microwave surface. Other parameters such as the presence of inclusions in the ground (holes, stones), or soil texture can also disrupt measurements. The aim of the work that we present in this paper is to develop a numerical model to simulate complex geological structures. This model must take into account all parameters that can affect the equivalent permittivity measured by the radiometer (surface, moisture variation ,... inclusions). The purpose of this model is to calculate the equivalent permittivity of these geological structures in order to be able to associate with each radiometer measurement an equivalent moisture.