Journal of Arid Meteorology

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Variation Characteristics of Soil Temperature and Moisture During the Freezing and Thawing Periods in Alpine Wetland in Qinghai-Tibetan Plateau

QUAN Chen1, ZHOU Bingrong1, ZHU Shengcui2, XIAO Hongbin1, SHEN Xiaoyan1, LI Fu1   

  1. 1. Institute of Meteorological Science of Qinghai Province, Key Laboratory of Disaster Prevention and Mitigation of Qinghai Province, Xining 810000, China;
    2. Haibei Pastoral Meteorology Experimental Station of Qinghai Province, Haibei 810200, Qinghai, China
  • Online:2018-04-30 Published:2018-04-30

青藏高原高寒湿地冻融过程土壤温湿变化特征

权  晨1周秉荣1朱生翠2肖宏斌1沈晓燕1,李  甫1   

  1. 1.青海省气象科学研究所,青海省防灾减灾重点实验室,青海西宁810000;
    2.青海省海北牧业气象试验站,青海海北810200
  • 通讯作者: 周秉荣(1974— ),男,青海湟中人,高级工程师,主要从事应用气象及生态恢复学研究. E-mail:zbr0515@foxmail.com。
  • 作者简介:权晨(1990— ),男,青海乐都人,工程师,主要从事高寒生态气象及气候变化研究. E-mail:quanchen007@sina.com。
  • 基金资助:

    国家重点研发计划——三江源区退化高寒生态系统恢复技术及示范第三课题“退化高寒湿地近自然恢复及生态功能提升技术与示范”(2016YFC0501903)、第三次青藏高原大气科学试验“青藏高原影响及下游灾害天气的诊断与预报”(GYHY201406001)和青海省科技计划项目(2017-HZ-801)共同资助

Abstract:

As the sources of some large rivers, the freeze-thaw process of alpine wetland in Qinghai-Tibetan Plateau is of great importance to regional and downstream ecosystem and climate regulation. Based on soil temperature and moisture observation data at Longbao test station of Yushu prefecture which is located in three rivers source area on Qinghai-Tibetan Plateau, the diurnal and seasonal variation characteristics of soil temperature and water content in the freezing and thawing processes were analyzed, especially during the freezing and thawing conversion period. The results indicate that the soil temperature and water content of alpine wetland had obvious seasonal variations in the freezing and thawing periods. The soil temperature was high in summer and low in winter. The profile values of soil temperature successively increased at 5 cm, 40 cm, 20 cm, 30 cm, 10 cm depth during the freezing period. On the contrary, it decreased in sequence at 5 cm, 40 cm, 20 cm, 30 cm and 10 cm depth during the thawing period. The soil water content reduced gradually from top to bottom in the freezing period, while it increased from top to bottom during the thawing period. The soil temperature in surface layer (5 cm) and deep layer (40 cm) in alpine wetland had diurnal variation characteristics, the diurnal variation in surface layer was more significant than that in deep layer, and the variation range was biggest in summer. However, the soil water content was stable in a day except for a certain fluctuation in surface layer. The vertical distribution of soil temperature presented a three-layer structure due to the temperature differences between that at 10 cm, 30 cm depth and their adjacent layers during the freeze-thaw transition period, while the soil water content appeared obvious regular changes, it decreased in the freezing period and increased in the thawing period with the increase of depth, and the change of soil water content in deep layer was later than that in shallow layer.

Key words: alpine wetland, soil temperature and moisture, characteristics of freezing and thawing, freezing and thawing conversion period

摘要:

青藏高原高寒湿地作为大江大河支流的发源地,其冻融过程对该地区及下游的生态系统和气候调节有重要意义。利用青藏高原腹地三江源区隆宝高寒湿地试验站的高时间分辨率土壤温湿数据,对冻融过程中土壤温湿的季节、日以及冻融转换期变化特征进行分析和探讨。结果表明:(1)高寒湿地土壤冻融过程中,土壤温度整体表现出夏高冬低的变化特征,冻结期5 cm、40 cm、20 cm、30 cm和10 cm地温依次增大,地温随深度变化存在一定的不规律性,而非冻结期则正好相反;土壤湿度在冻结期自上而下逐渐降低,融化期自上而下逐渐增加。(2)土壤表层5 cm和深层40 cm地温存在显著的日变化特征,表层较深层变化更显著,且夏季变化幅度最大;土壤含水率较稳定,除表层有一定波动,其他各层无明显日变化。(3)冻融转换期,土壤温度垂直分布存在显著的三层结构,10 cm和30 cm处与邻近层的温度差异是导致这种特殊分布的主要原因;随着深度的加深,土壤含水率冻结期(融化期)逐渐增加(减少),且深层比浅层的变化时间明显滞后。

关键词: 高寒湿地, 土壤温湿, 冻融特征, 冻融转换期

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