城市土壤热扩散率实验研究

Experiment of Soil Thermal Diffusivity in Cities

为了获得城市边界层能量特征,于2004年7～8月分别在合肥、南京两地采集土壤温度数据,并分析获得两地的土壤热扩散率v_g。由于数据采集存在差异,采用不同的处理方式分析数据:采用振幅变化法分析合肥地区水银地温温度计及计算机系统采集的数据,得到其深度15cm以上土壤层的土壤热扩散率v_g值为1.665×10^(-7)～4.687×10^(-7)m^2/s,v_g值随深度加深而增加;利用热传导方程设计的差分格式分析合肥(铂电阻地温温度计-计算机采集系统采集数据)、南京浦口两地数据,结果表明合肥土壤深度10cm处的v_g值为2×10^(-7)m^2/s,南京土壤深度5～20 cm之间的v_g值为2.1×10^(-7)～6.5×10^(-7)m^2/s,其v_g值随深度变化而变化,趋势与合肥一致。最后比较了合肥、南京两地土壤热扩散率v_g值的差异,对同一土壤深度,南京地区的土壤热扩散率v_g值略大于合肥地区。

For the characteristics of urban boundary layer and energy budget, experiments were carried in Hefei and Nanjing city during the summer of 2004, and values of the soil thermal diffusivity Vg were obtained. Accoding to the characteristics of the data, they were processed in two ways. The amplitudes of soil temperature fluctuation were analyzed in the data collected by mercurial geothermometer and platonic geothermometer linked with a computer in Hefei. The value of Vg above the depth of 15 cm is 1.665 ×10^-7 - 4.687 × 10^-7 m^2/s, and the Vg increased with the depth. Different methods from heat conduct equation were used to calculate Vg. The value of Vg in depth of 10 cm was 2.1 × 10^-7 m^2/s in Hefei. In Nanjing, the values of Vg in the depth between 5 cm and 20 cm ranged from 2.1 × 10^-7 m^2/s to 6.5 × 10^-7 m^2/s, and they increased with the depth too. In the end, the values of Vg were discussed and compared between Hefei and Nanjing. For the same depth, the values of Vg in Nanjing are larger than them in Hefei.