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冰川冻土 ›› 2022, Vol. 44 ›› Issue (2): 355-365.doi: 10.7522/j.issn.1000-0240.2022.0042

• 第二次青藏高原综合科学考察研究 •    

青藏高原热喀斯特湖演化及其对多年冻土的热影响模型计算研究

尹国安(), 牛富俊, 林战举, 罗京, 刘明浩   

  1. 中国科学院 西北生态环境资源研究院 冻土工程国家重点实验室,甘肃 兰州 730000
  • 收稿日期:2021-06-14 修回日期:2022-04-10 出版日期:2022-04-30 发布日期:2022-06-10
  • 作者简介:尹国安,副研究员,主要从事多年冻土变化模拟及灾害效应研究. E-mail: yinguoan@lzb.ac.cn
  • 基金资助:
    第二次青藏高原综合科学考察研究项目(2019QZKK0905);国家自然科学基金项目(41801037)

Study on numerical modeling of thermokarst lake evolution and its thermal impacts on permafrost on the Qinghai-Tibet Plateau

Guo’an YIN(), Fujun NIU, Zhanju LIN, Jing LUO, Minghao LIU   

  1. State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
  • Received:2021-06-14 Revised:2022-04-10 Online:2022-04-30 Published:2022-06-10

摘要:

青藏高原热喀斯特湖分布广泛,近年来在气候变暖背景下快速发展。热喀斯特湖的形成和发展与地下冰含量及气候变化有着密切关系,强烈影响多年冻土的热稳定性。为了更深入理解在气候变暖背景下热喀斯特湖的发展及其对下伏多年冻土的影响,以青藏高原北麓河地区一个典型热喀斯特湖的长期监测数据为资料,发展了耦合大气—湖塘—冻土三个过程要素的一维热传导模型,模拟了四种不同深度热喀斯特湖在气候变暖背景下的发展规律及其对多年冻土的热影响。结果表明:浅湖(<1.0 m)在目前稳定气候背景下处于较稳定状态,湖冰能够回冻至湖底,对下伏多年冻土影响较小;较深湖塘(≥1.0 m)冬季不能回冻至湖底,湖深不断增加,且底部在50年内将会形成不同深度的融区。随着气候变暖,热喀斯特湖的热效应显著,深度快速增加,较深湖塘的最大湖冰厚度减小,底部多年冻土快速融化形成开放融区。研究将有助于理解气候变化对青藏高原多年冻土区地貌演化及水文过程的影响。

关键词: 气候变化, 湖冰, 融区, 地温, 数值模型, 青藏高原, 热喀斯特湖

Abstract:

Thermokarst lakes are widespread and increasing due to climate change on the Qinghai-Tibet Plateau (QTP). They were formed by the ground subsidence in ice-rich permafrost landscapes and have strong impacts on permafrost thermal states. To gain a deep understanding of lake evolution and its thermal impacts on permafrost, here, a one-dimensional numerical model coupled lake and subsidence processes was developed. This model was validated using the field measurements of lake depth, lake ice and ground temperatures in Beiluhe Basin. Impact simulations for thermokarst lake with various depths were performed under current climate conditions as well as under a strong climate warming scenario. The simulation results indicated that in current climate, the shallow lakes (<1.0 m) were stabilized and lake water could freeze back to the bottom in winter, while the deep lakes (≥1.0 m) could deepen constantly and not freeze to their base. These deep lakes rose the bottom temperature and accelerated thawing of the underlying permafrost as well as developing of taliks in 50 years. Under a strong climate warming, all lakes deepened and warmed the underlying permafrost. The ice thickness increased for the shallow lakes, but decreased for the deep lakes. An open talik was likely to form under the deep lakes. Such changes could significantly alter the landforms and hydrology in permafrost regions on the QTP.

Key words: climate change, lake ice, talik, ground temperature, numerical model, Qinghai-Tibet Plateau, thermokarst lake

中图分类号: 

  • P642.14