青藏高原含砂砾石土壤导热率实验研究

发布时间：2018-02-20 15:06

本文关键词： 导热率青藏高原砂砾石含水量孔隙度　出处：《冰川冻土》2017年02期 　论文类型：期刊论文

【摘要】：土壤导热率是土壤的基本物理参数之一,也是陆面模式的重要输入量,对研究土壤热传输、水热耦合运移有重要意义。青藏高原由于独特的地理环境备受学者关注,但目前常用的土壤水、热属性参数化方案仅仅考虑了沙土、粉土和黏土,就砂砾石重要性的认识还不足,很少有模式模拟砾石对青藏高原多年冻土和高寒草地的影响。采用便携式热导仪(KD2 Pro,DECAGON,美国)测量了青藏高原玛多和北麓河两地典型土壤在冻结和未冻结状态下不同水分条件时的土壤导热率,分析了砂砾石含量对土壤孔隙度的影响及冻结和未冻结状态下,不同水分条件下砂砾石含量对土壤导热率的影响。结果表明:当含水量高于某一阈值时,含水土壤冻结状态下的导热率高于未冻结状态下的导热率;土壤含水量对土壤导热率影响显著,导热率随着含水量的增加而增大,在含水量较小时变化更明显;砂砾石含量比重多的土壤孔隙度较小,且砂砾石含量越大的土壤在冻结状态下导热率高。以上结果表明,砂砾石对土壤导热率有显著影响,在将来的模式模拟研究中必须考虑砂砾石对土壤热属性的影响,进而提高土壤水热过程模拟的精度。
[Abstract]:Soil thermal conductivity is one of the basic physical parameters of soil, and it is also an important input of land surface model, which is of great significance for the study of soil heat transfer and coupled transport of water and heat. The Qinghai-Tibet Plateau has attracted much attention due to its unique geographical environment. However, the commonly used parameterization schemes for soil water and thermal properties only consider sand, silt and clay, and the importance of sand and gravel is not well understood. Few models simulate the effects of gravel on permafrost and alpine grassland over the Qinghai-Xizang Plateau. A portable thermal conductivity instrument KD2 Pron DECAGON (USA) was used to measure the typical soils of Mado and Beilu in the Qinghai-Xizang Plateau under frozen and unfrozen conditions. Soil thermal conductivity under the same water condition, The effect of sand gravel content on soil porosity and the effect of sand gravel content on soil thermal conductivity under different moisture conditions were analyzed. The results showed that when the water content was higher than a certain threshold, The thermal conductivity of water-bearing soil was higher than that of non-frozen soil, and the soil moisture content had a significant effect on the soil thermal conductivity, and the thermal conductivity increased with the increase of water content, and the change of soil moisture content was more obvious when the water content was small. The porosity of the soil with more specific gravity of gravel is smaller, and the higher the content of gravel is, the higher the thermal conductivity of the soil is under the freezing state. The results show that the sand and gravel have a significant effect on the thermal conductivity of the soil. The influence of gravel on soil thermal properties must be taken into account in the future model simulation study, and the accuracy of soil hydrothermal process simulation should be improved.
【作者单位】：中国科学院西北生态环境资源研究院;中国科学院大学;南通大学;
【基金】：国家重点基础研究发展计划项目(2013CBA01807) 国家自然科学基金项目(41271089;41422102)资助
【分类号】：S152

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