热脉冲技术测定土壤热通量的原理和方法

正土壤热通量是地表能量平衡的重要组成部分,是研究陆-气能量交换的主要物理量。在农林业研究上,大部分土壤热通量研究主要关注于土壤热通量对种子萌发、植物根系生长、小气候效应、土壤碳氮循环过程的影响1-3];在地球物理学和土木工程学研究上,重点研究土壤热通量在大地热流、埋地管道、地铁工程等方面的应用4-5]。传统的土壤热通量测定方法主要是土壤热通量板直接测定法,但对土壤的扰动比较大。由于存在一定的厚度,土壤热通量板其自身导热材料的传热性能和土壤会存在差异,导致热通量

Soil Heat Flux Measurement Based on Heat Pulse Method

The principles and methods of measuring soil heat flux with three-needle heat pulse sensor are introduced based on the theory of thermophysics. The soil heat flux plate method was employed to validate the heat pulse method. The results indicated that the soil heat flux calculated by the heat pulse method generally agreed well with the soil heat flux plate method. Compared with the soil heat flux plate, the bias of heat pulse method was 0.674 W·m^-2. It proved that the heat pulse method was able to provide accurate soil heat flux measurement. Analysis on the phase of soil heat flux showed that the time of the maximum value occurred had 1 hour's hysteresis for the soil temperature compared to the soil heat flux. Due to the advantage of lower soil disturbance and contact resistance, the heat pulse method will have a wide prospect.