THE SUBSURFACE TRANSPORT OF HEAT AND MOISTURE AND ITS EFFECT ON THE ENVIRONMENT - A NUMERICAL-MODEL

A numerical model was developed to study the transport of heat and vapor under the surface of bare soil and soil covered by some materials such as asphalt and concrete under no rainfall conditions. The computational results provide a good match with the experimental data. The results show that the transport of water vapor inside the soil has an important effect on the subsurface distribution of temperature, especially for bare soil. Because of evaporation, the temperature of bare soil is much lower than that under covered surfaces throughout the day and the temperature of the surface covered by asphalt is extremely high - higher than the atmospheric temperature even at night. An increase of thickness of the covering material further increases the temperature and heat stored under surfaces. Tle stored heat is released to the atmosphere at night, contributing to environmental effects such as the urban heat island.