青藏高原那曲地区非均质土壤导温率的变化及土壤温度数值模拟

土壤中的热传输是地-气能量交换的组成部分,而非均质土壤导温率/导热率的获得是研究土壤热传输过程中的一个难点,是至今仍未很好解决的问题.分析了一维热传导方程在非均质土壤条件下的适用形式,利用青藏高原那曲站实测土壤温度资料,计算了非均质土壤导温率,计算结果表明,土壤导温率有明显的随深度和季节的变化.利用考虑非均质土壤导温率参数的土壤温度数值模式,对那曲地区各层土壤温度的年变化进行了模拟试验,模拟结果显示,按冷季和暖季分别采用两组不同的土壤导温率,对土壤温度的年变化已有较好的模拟效果.

Variation of Thermal Diffusivity and Temperature Simulation of Soils of Vertical Heterogeneity in Nagqu Prefecture in the Tibetan Plateau

Soil thermal transport is an important constituent part in energy exchange process between land and atmosphere.Variances of soil thermal diffusivity in soil of vertical heterogeneity are the key factors in soil thermal transport.But it is difficult and still not solved commendably to get the soil thermal diffusivity in soil of vertical heterogeneity.In this paper,the practicable form of the one-dimension thermal conduction equation in soil of vertical heterogeneity is analyzed.The thermal diffusivities of soil of vertical heterogeneity are calculated based on the observation data of multilevel soil temperatures in Nagqu Prefecture in the Tibetan Plateau.The calculation results show that the soil thermal diffusivity has obvious variation with depth and season.The annual variations of soil temperature at each level are simulated by using a simple soil temperature numerical model which the thermal diffusivities of soil of vertical heterogeneity are employed.Using two set of soil thermal diffusivity values in the cold and warm seasons,the simulation results show that the simulating effect is better for annual variation process of soil temperature.