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冰川冻土 ›› 2013, Vol. 35 ›› Issue (3): 528-540.doi: 10.7522/j.issn.1000-0240.2013.0062

• 冰冻圈与全球变化 • 上一篇    下一篇

积雪和有机质土对青藏高原冻土活动层的影响

张伟1, 周剑1, 王根绪2, Wolfgang Kinzelbach3, 程国栋1, 叶柏生1, 何晓波1, 李弘毅1   

  1. 1. 中国科学院寒区旱区环境与工程研究所, 甘肃 兰州 730000;
    2. 中国科学院成都山地灾害与环境研究所, 山地表生过程与生态调控重点实验室, 四川 成都 610041;
    3. Institute of Environmental Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 15, 8093 Zurich, Switzerland
  • 收稿日期:2012-12-10 修回日期:2013-03-11 出版日期:2013-07-25 发布日期:2013-07-25
  • 作者简介:张伟(1983- ), 男, 河南南阳人, 2013年在兰州大学获硕士学位,现为中国科学院寒区旱区环境与工程研究所在读博士研究生,主要从事寒区水文过程模拟研究.E-mail: zw_2010@lzu.edu.cn
  • 基金资助:

    国家重大科学研究计划项目(2013CBA01806); 国家自然科学基金项目(40925002;41271079); 冻土工程国家重点实验室开放基金(SKLFSE201005)联合资助

Monitoring and Modeling the Influence of Snow Cover and Organic Soil on the Active Layer of Permafrost on the Tibetan Plateau

ZHANG Wei1, ZHOU Jian1, WANG Gen-xu2, Wolfgang Kinzelbach3, CHENG Guo-dong1, YE Bai-sheng1, HE Xiao-bo1, LI Hong-yi1   

  1. 1. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou Gansu 730000, China;
    2. Key Laboratory of Terrestrial Processes in Mountainous Regions and Ecological Control, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu Sichuan 610041, China;
    3. Institute of Environmental Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 15, 8093 Zurich, Switzerland
  • Received:2012-12-10 Revised:2013-03-11 Online:2013-07-25 Published:2013-07-25

摘要:

随着全球气候变暖, 青藏高原冻土活动层正在逐渐加深, 为了理解积雪和表层有机质土壤对冻土活动层的影响机理, 一维水热耦合模型CoupModel被用于模拟气象驱动下土壤冻融的动态过程.基于祁连山冰沟和青藏高原唐古拉站长期监测数据, CoupModel模型被成功的率定和验证.在冰沟站验证的模型被用于研究积雪对冻土活动层的影响, 结果显示: 目前较浅积雪情景(雪深<20 cm)比完全忽略积雪的情景模拟的冬季土壤冻结深度深, 说明青藏高原现状下较浅的积雪有利于冻土发育. 原因是雪面较高的反照率造成地表吸收的太阳辐射减少, 导致雪面温度较低, 加之浅雪的阻热性能又较小, 综合导致浅雪覆盖时表层土壤向大气释放的能量增加. 但随着积雪深度逐渐增加, 模拟的冬季土壤冻结深度反而越来越浅, 说明较厚的积雪(>20 cm的雪深)并不利于冻土的发育, 主要是雪相对于空气低的热传导隔绝了表层土壤向大气的热损失. 在唐古拉站验证的模型被用于研究有机质土对冻土活动层的影响, 结果显示: 随着有机质土壤深度增加, 模拟的活动层夏季融化深度逐渐较小. 有机质土壤较矿物质土壤低的热传导和高的热容性质减少了下伏土壤热状况对太阳辐射和气温波动的响应, 说明有机质土有利于冻土的保护.

关键词: 青藏高原, 冻土活动层, 有机质土壤, 积雪, CoupModel

Abstract:

The most important factors affecting the active layer depth and distribution of permafrost on the plateau are snow cover and thickness of the organic soil layer, except for air temperature and solar radiation.In this study, data from two typical field sites (Binggou Station and Tanggula Station) on the plateau were used.The two stations were established by the CAREERI, CAS to monitor the impact of snow cover and organic soil layer on the energy balance and thermal state within the active layer.In order to find the process-based explanations for the recent monitoring results, the one-dimensional heat and water flow model CoupModel was used to calculate the vertical heat and water fluxes in a soil-snow-atmosphere system for climatic conditions at the two field sites.The model was successfully adjusted and applied to simulate the active layer dynamics under a surface covered by snow and tundra soil conditions.Subsequently, the model was used to investigate the effects of snow cover and organic soil layer on the active layer.The investigation on the influence of snow cover on the active layer at Binggou Station revealed that snow cover depth is the key to the effect of snow cover on the active layer.The shallow snow cover (less than 20 cm) is advantageous to frozen soil development.The thick snow cover in winter obviously insulates the subsoil against energy losses to the atmosphere.The frozen active layer depth is reduced and not conducive to the conservation of permafrost.Sensitivity study shows that the thawing depth of the active layer decreases with organic increasing.The organic layer makes the underlying soil less responsive to solar radiation and air temperature fluctuations, owing to its low thermal conductivity and high heat capacity, and thus provides a protection against permafrost thawing.Both influences are of importance for the behavior of permafrost under global warming.

Key words: Tibetan Plateau, active layer of permafrost, organic soil, snow cover, CoupModel

中图分类号: 

  • P642.14