ANALYTICAL MODEL TO PREDICT ANNUAL SOIL SURFACE-TEMPERATURE VARIATION

An analytical model is developed to predict the annual variation of so il surface temperature from readily available weather data and soil th ermal properties. The time variation is approximated by a first harmon ic function characterized by an average an amplitude, and a phase lag. A parametric analysis is presented to determine the effect of various factors such as evaporation, soil absorptivity and soil convective pr operties on soil surface temperature. A comparison of the model predic tions with experimental data is presented. The comparative analysis in dicates that the simplified model predicts soil surface temperatures w ithin ten percent of measured data for five locations.