• 标题：Evaluation of 11 soil thermal conductivity schemes for the permafrost region of the central Qinghai-Tibet Plateau
• 关键词：Soil thermal conductivity;Scheme;Freeze-thaw cycle;Permafrost;Qinghai-Tibet Plateau
• 作者：

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Soil thermal conductivity (λ), which describes the ability of the soil to transfer heat, is critical to understand the thermal regime of ground surfaces. In this study, in situ measurements of λ were conducted at two field sites in the permafrost region of the central Qinghai-Tibet Plateau (QTP) and the results were used to evaluate 11 schemes of λ at depths of 10–50 cm during the freeze-thaw cycle period. Our analyses revealed that λ had a remarkable seasonal variation, due to the significant effects of soil moisture content and ice-water phase changes as temperature changed during the freeze-thaw cycle period. Among the selected schemes, the Johansen scheme, its three derivatives (i.e., the He scheme, Yang scheme and Zhao scheme), and the Campbell scheme were significantly superior to others. Moreover, the Johansen scheme ranked among the top schemes for frozen soil, while the Campbell scheme gave the most accurate values for unfrozen soil. The effects of different estimation methods of quartz content (q), dry λ and the Kersten number (Ke) on the predicted schemes results were also evaluated. The results showed that, the methods used for the estimation of q and Ke had the greatest influence on the calculation results for the permafrost region. Overall, this research provides insights for the development of a λ scheme for the permafrost region of the central QTP.