Influence of the soil-atmosphere interface interactions on the soil water content and temperature profiles
Résumé
This paper presents the results of a series of numerical analyses aiming to predict temperature, water content, and pore-water pressure changes due to climatic effects in a soil profile during a long term period by considering the soil atmosphere interface interactions. A soil-atmosphere interface model is used to calculate the evaporation rate and heat flux on the soil surface; the water transport equations (liquid--Darcy's law and vapor--Fick's law) coupled to heat flow equation (de Vries 1963) are solved to determine the profiles of soil temperature, water content or pore water pressure. A sensitivity analysis was also carried out to study how the variations of the soil albedo value (i.e., the ratio of reflected to incident solar radiation), the saturated hydraulic conductivity and the Initial Temperature Profiles (ITP) can influence water content, suction and temperature changes. Our analysis uses field measurements in Mormoiron, France, carried out from 2004 to 2005. The results show that the active zone (where the suction profile is influenced by seasonal environmental changes) is generally about 1.5 m deep in the investigated region. The results also suggest that the ITP can affect the temperature profiles but its influence on the suction and water content profiles is very small. During the cold season, precise albedo values are not very important nor very sensitive in influencing the water balance.