Investigating soil thermodynamic parameters of the active layer on the northern Qinghai-Tibetan Plateau

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• 作者：Ren Li (1)
  Lin Zhao (1)
  Tonghua Wu (1)
  Yongjian Ding (1)
  Yao Xiao (1)
  Yongliang Jiao (1)
  Yanhui Qin (1)
  Yufei Xin (2)
  Erji Du (1)
  Guangyue Liu (1)
  
• 关键词：Qinghai ; Tibetan Plateau ; Active layer ; Permafrost ; Soil thermodynamic parameters ; Unfrozen water content
• 刊名：Environmental Earth Sciences
• 出版年：2014
• 出版时间：January 2014
• 年：2014
• 卷：71
• 期：2
• 页码：709-722
• 全文大小：568 KB
• 作者单位：Ren Li (1)
  Lin Zhao (1)
  Tonghua Wu (1)
  Yongjian Ding (1)
  Yao Xiao (1)
  Yongliang Jiao (1)
  Yanhui Qin (1)
  Yufei Xin (2)
  Erji Du (1)
  Guangyue Liu (1)
  
  1. Cryosphere Research Station on the Qinghai-Tibet Plateau, State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China
  2. Chinese Academy of Meteorological Sciences, Beijing, 100081, China
  
• ISSN：1866-6299

文摘

The soil thermodynamic parameters, including thermal conductivity, diffusivity and volumetric capacity within the active layer on the northern Tibetan Plateau, were calculated using the measured data of soil temperature gradient, heat flux, and moisture at four stations from October 2003 to September 2004. The results showed that the soil thermodynamic parameters exhibited clear seasonal fluctuation. The thermal conductivity and diffusivity in summer and autumn at Beiluhe, Kexinling, and Tongtianhe were larger than those in winter. The volumetric thermal capacity causes an opposite change; it was larger in autumn and winter than in summer. In spring, the soil thermal conductivity at the Kekexili station was larger than that in summer. Generally, fine-grained soils and lower saturation degrees in the topsoil might be a reason for the lower soil thermal conductivity in winter. For a given soil, soil moisture was the main factor influencing the thermodynamic parameters. The unfrozen water content that existed in frozen soils greatly affected the soil thermal conductivity, whose contribution rate was estimated to be 55?%. The thermodynamic parameters of frozen soils could be expressed as a function of soil temperature, volumetric ice content and soil salinity, while for the unfrozen ground the soil moisture content is the dominant factor for those thermal parameters. As for the soil thermal diffusivity, there exists a critical value of soil moisture content. When the soil moisture content becomes less than a critical value, the soil thermal diffusivity increases as the soil moisture content rises.