青藏高原唐古拉多年冻土区冻融循环过程中的能量平衡特征
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青藏高原唐古拉多年冻土区冻融循环过程中的能量平衡特征
1.中国科学院 西北生态环境资源研究院 冰冻圈科学国家重点实验室/青藏高原冰冻圈观测研究站,甘肃 兰州 730000
2.中国科学院大学,北京 100049
Surface Energy Processes during Freeze-thaw Cycle in Tanggula Permafrost Region of Qinghai-Tibet Plateau
Abstract: There are few studies on the influence of the freeze-thaw cycle on surface energy in the permafrost region of the Qinghai-Tibet plateau. Based on the measured data of Tanggula permafrost, to divides each stage of the freeze-thaw cycle of the active layer according to the 10 cm soil temperature. Combine with surface energy closure and surface energy fluxes to discuss the influence between freeze-thaw cycle of active layer and water-heat exchange. The results show that: each stage of the freeze-thaw cycle of the active layer is affected by climate change. The starting time of the thawing process is advancing and the starting time of the freezing process is delayed. As a result, the duration of soil complete thawing increases and gradually approaches that of complete freezing; in different freeze-thaw states of shallow soil, the energy closure rate different is large, and the energy closure in the stage of complete thawing is generally better than that in the stage of complete freezing; The net radiation value in the stage of complete melting is higher than that in the stage of complete freezing, sensible heat flux dominates in the stage of complete freezing, latent heat flux dominates in the stage of complete melting, and surface soil heat flux is positive in the stage of complete melting and negative in the stage of complete freezing.
1.Cryosphere Research Station on the Qinghai-Tibet Plateau, State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
2.University of Chinese Academy of Sciences, Beijing 100049, China
摘要:
摘 要:青藏高原多年冻土区冻融循环过程对地表能量及其分配的影响研究相对较少,本文基于青藏高原唐古拉站多年冻土的实测资料,依据10 cm土壤温度划分浅层土壤冻融循环的各个阶段并结合能量闭合率、地表能量各通量等数据探讨浅层土壤冻融循环过程与地气间水热交换过程之间的影响。结果表明:浅层土壤冻融循环过程各阶段均受气候变化的影响,其融化过程起始时间提前同时冻结过程起始时间推后,完全融化阶段持续时间增加,且逐渐接近完全冻结阶段持续时间;在浅层土壤不同冻融状态下,能量闭合率差值较大,其中完全融化阶段能量闭合状况普遍好于完全冻结阶段;净辐射值在完全融化阶段高于完全冻结阶段,净辐射在完全冻结阶段主要转化为感热通量,在完全融化阶段主要转化为潜热通量,地表土壤热通量在完全融化阶段为正值,在完全冻结阶段为负值。
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