土壤热传导方程解析解和那曲地区土壤热扩散率研究

STUDY ON ANALYTICAL RESOLUTION TO SOIL THERMAL CONDUCTIVE EQUATION AND SOIL THERMAL DIFFUSIVITY OVER NAGQU AREA

文中用Laplace变换推导了土壤热传导方程的解析解和包含热对流项的土壤热传导方程的解析解。用青藏高原 8个土壤湿度、温度廓线观测站 1998年 9月 4日到 10日实测资料基础上 ,根据谐波方法和Laplace变换方法得到了土壤热传导方程的解析解 ,计算了这些站的总体土壤热扩散率 ;用包含热对流项的土壤热传导方程的解析解计算了土壤热扩散率。结果表明 :对于一个深度从 0 .0 4～ 0 .2 0m的浅薄土壤层 ,总体土壤热扩散率的值为 0 .30×10 -6～ 0 .98× 10 -6m2 /s,土壤热扩散率的值为 0 .15× 10 -6～ 0 .72× 10 -6m2 /s。由谐波方法得到的总体土壤热扩散率比由Laplace变换的值稍大 ;

The soil thermal conductive equation and that with thermal convection term contained were solved analytically. Based on the observation data from soil moisture and temperature measurement system(SMTMS)sites during GAME/Tibet over Tibetan Plateau in September 4-10,1998,we calculate the apparent soil thermal diffusivity by harmonic method(HM)and Laplace transform method (LTM), and the soil thermal diffusivity by the analytical resolution to soil thermal conductive equation with thermal convection term contained.This study demonstrates that the apparent soil thermal diffusivity in this area over the Tibetan Plateau is between 0.30×10 -6 and 0.98×10 -6 m 2/s in the upper layer(at depths 0.04 m to 0.20 m)where the soil thermal diffusivity should be between 0.15×10 -6 and 0.72×10 -6 m 2/s. Harmonic method(HM)leads to somewhat greater values of the apparent soil thermal diffusivity than the LTM method,furthermore,apparent soil thermal diffusivity is greater than soil thermal diffusivity.