ANALYTICAL MODEL TO PREDICT NONHOMOGENEOUS SOIL-TEMPERATURE VARIATION

This paper presents an analytical model to predict the temperature var iation within a multilayered soil. The soil surface temperature is ass umed to have a sinusoidal time variation for both daily and annual tim e scales. The soil thermal properties in each layer are assumed to be uniform. The model is applied to two-layered, three-layered, and to no nhomogeneous soils. In case of two-layered soil, a detailed analysis o f the thermal behavior of each layer is presented. It was found that a s long as the order of magnitude of the thermal diffusivity of soil su rface does not exceed three times that of deep soil; the soil temperat ure variation with depth can be predicted accurately by a simplified m odel that assumes that the soil has constant thermal properties.