干旱区研究 ›› 2019, Vol. 36 ›› Issue (6): 1568-1575.

• 陆面过程 • 上一篇    下一篇

季节性冻土区土体冻融过程及其对水热因子的响应

乌艺恒1,赵鹏武12,周梅12,魏江生3,冯倩倩1   

  1. 1.内蒙古农业大学林学院,内蒙古 呼和浩特 010019; 2.内蒙古赛罕乌拉森林生态系统国家野外观测研究站,内蒙古 赤峰 025150; 3.内蒙古农业大学草原与资源环境学院,内蒙古 呼和浩特 010011
  • 收稿日期:2019-01-10 修回日期:2019-03-08 出版日期:2019-11-15 发布日期:2019-11-15
  • 通讯作者: 周梅
  • 作者简介:乌艺恒(1992-),女,博士研究生,从事森林生态学研究. E-mail: uykhan@163.com
  • 基金资助:
    国家自然科学基金重点项目(41530747)资助

Freezing-thawing Process of Seasonal Frozen Soil and Its Response to Moisture and Temperature

WU Yi-heng1, ZHAO Peng-wu1, 2, ZHOU Mei1, 2, WEI Jiang-sheng3, FENG Qian-qian1   

  1. 1. College of Forestry, Inner Mongolia Agricultural University, Hohhot 010019, China;
    2. Saihanwula National Forest Ecosystem Research Station, Chifeng 025150, Inner Mongolia, China;
    3. College of Grassland Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011 China

  • Received:2019-01-10 Revised:2019-03-08 Online:2019-11-15 Published:2019-11-15

摘要: 利用内蒙古赛罕乌拉森林生态系统国家野外观测研究站试验地的森林小气候观测塔,根据2015—2016年冻融期野外观测的气温、降水量、土壤温度和水分数据,对该区季节性冻土的冻融过程和特点进行了分析,研究了土壤冻结和解冻过程中各土壤层的垂直温度和水分的变化,以及对气温和降水量的响应。结果表明:①季节性冻土的土壤温度随着土层深度增加,土壤冻结和融化滞后天数也会增加,同时与气温的相关性也逐渐减小;②季节性冻土解冻的速度要快于冻结的速度;③在进入解冻期前,3月中旬到5月中旬,各层土壤温度始终保持在-1~1 ℃之间,不随气温波动;④降水量并不大的解冻期,土壤未冻水含量会迅速增加,说明冻融过程确实能够保存土壤水分,这将有利于植被应对春季干旱。

关键词: 季节性冻土, 冻融过程, 水热条件, 赛罕乌拉, 内蒙古

Abstract: The data of air temperature, precipitation and soil temperature and moisture content during the soil freezing-thawing period from 2015 to 2016 were obtained from the forest microclimate observation tower of Saihanwula National Forest Ecosystem Research Station in Inner Mongolia. The freezing-thawing process and characteristics of seasonal frozen soil in this area were analyzed. The vertical changes of soil temperature and moisture content and their responses to temperature and precipitation were studied. The results showed: ①The temperature of the seasonal frozen soil at different stages changed, the shallow soil began to freeze or thaw at first, and the lag time of freezing-thawing process increased gradually with the increase of soil depth. Moreover, the correlation between the air temperature and soil temperature decreased gradually; ②The thawing speed of frozen soil was higher than that of freezing: ③Before thawing (roughly from mid-March to mid-May), soil temperature at different depths maintained in a range of -1-1℃ and did not fluctuate with air temperature; ④The unfrozen water content in soil increased rapidly during the thawing period when the precipitation was not high, which indicated that the freezing and thawing processes could hold soil moisture and benefit the vegetation growth against spring drought.

Key words:  seasonal frozen soil; freezing-thawing process, moisture and temperature condition, Saihanwula, Inner Mongolia