HR: 0800h
AN: H21D-0743    [Abstracts]
TI: An Improved Force-Restore Method for Soil Temperature Prediction
AU: Gao, Z
EM: zgao@mail.iap.ac.cn
AF: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physic, Box 9804, Beijing, 100029, China
AU: Horton, R
EM: rhorton@istate.edu
AF: Iowa State University, Department of Agronomy, Ames, IA 50011, United States
AU: * Wang, Z
EM: zfwang@mail.iap.ac.cn
AF: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physic, Box 9804, Beijing, 100029, China
AU: Wang, L
EM: lwang@mail.iap.ac.cn
AF: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physic, Box 9804, Beijing, 100029, China
AB: The force-restore method was originally developed to enable soil temperature predictions. The method is currently used in many hydro-meteorological models. The force-restore method assumes that soil is uniform with depth. The method also assumes that thermal conduction is the only heat transfer mechanism necessary for prediction of soil temperature. These assumptions hamper the applicability of the force-restore method to many natural soil conditions. The main objective of this study is to improve the force-restore method by extending it to include the possibility of soil heterogeneity with depth and to include the possible occurrence of convective heat transfer as well as conduction heat transfer in soil. The improved force-restore method presented in this paper is identical to the current force-restore method for the specific condition of vertically uniform, dry soil. The average soil temperatures calculated by the current and the revised force-restore methods for a shallow soil layer were compared with measured soil temperatures at a bare soil site in the China the Loess Plateau during the period from July 22 to 26, 2005. Results showed that the revised force-restore method gave a realistic estimate of soil temperature, especially during daylight periods, and the current force-restore method, on average, overestimated either the diurnal amplitude or the phase shift for the shallow soil layer. The revised force-restore method underestimated nighttime soil temperature because it did not account for the diurnal variation of convection heat transfer and the condensation of water vapor occurring in soil during nighttimes. Overall, the revised force-restore method estimated shallow soil temperature better than the current force-restore method.
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1847 Modeling
DE: 1849 Numerical approximations and analysis
DE: 1865 Soils (0486)
DE: 1894 Instruments and techniques: modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting