气候变化下大兴安岭南段季节冻土退化特征  

Seasonal Permafrost Degradation Characteristics in Southern Part of Greater Khingan Mountains under Climate Change

作　　者：孙逸晨 魏江生 舒洋 赵鹏武 齐桂萍[6] 张静 SUN Yi-chen;WEI Jiang-sheng;SHU Yang;ZHAO Peng-wu;QI Gui-ping;ZHANG Jing(College of Grassland Resources and Environment,Inner Mongolia Agricultural University,Hohhot 010011,Inner Mongolia,China;Saihanwula National Forest Ecosystem Research Station,Chifeng 025150,Inner Mongolia,China;College of Forestry,Inner Mongolia Agricultural University,Hohhot 010019,Inner Mongolia,China;Inner Mongolia Key Laboratory of Soil Quality and Nutrient Resource,Hohhot 010018,Inner Mongolia,China;Key Laboratory of Agricultural Ecological Security and Green Development at Universities of Inner Mongolia Autonomous,Hohhot 010018,Inner Mongolia,China;Qingshan Forest Farm,Chifeng 024200,Inner Mongolia,China;Saihanwula Nature Reserve Administration,Chifeng 025150,Inner Mongolia,China)

机构地区：[1]内蒙古农业大学草原与资源环境学院,内蒙古呼和浩特010011 [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]内蒙古农业大学林学院,内蒙古呼和浩特010019 [4]内蒙古自治区土壤质量与养分资源重点实验室,内蒙古呼和浩特010018 [5]农业生态安全与绿色发展自治区高等学校重点实验室,内蒙古呼和浩特010018 [6]内蒙古赤峰市青山林场,内蒙古赤峰024200 [7]内蒙古赤峰市赛罕乌拉自然保护区管理局,内蒙古赤峰025150

出　　处：《林业科学研究》2024年第3期86-94,共9页Forest Research

基　　金：国家重点研发计划课题(2022YFF0801801);国家自然科学基金(42230503)。

摘　　要：[目的]季节冻土退化会直接影响生长季初期的水分补给,进而影响区域森林健康。然而,目前大兴安岭南段的冻土退化,特别是气候变化下冻土如何退化尚不清楚。[方法]在内蒙古赛罕乌拉国家级自然保护区长期实验森林中,定位观测2014-2022年气温、土壤温度、土壤体积含水量等环境因子,分析森林季节冻土退化特征。[结果]研究表明:大兴安岭南段气温加速上升,1997-2022年间年平均气温上升速率为0.42℃·(10 a)^(-1),比1973-1996年间的升温速率[0.34℃·(10 a)^(-1)]加快了23.5%;且冻融期(当年11月-次年6月)平均气温上升速率更快[0.46℃·(10 a)^(-1)]。土壤的冻融模式呈自上而下单向冻结,单向融化;冻结速率、融化速率随着土壤深度的增加而变快,在40~80 cm土层达到最大值(冻结速率2.23 cm·d^(-1)、融化速率4.50 cm·d^(-1))。季节冻土持续退化,观测到的最大冻结深度由80 cm减少至40 cm;冻融期显著缩短,开始冻结时间推迟,完全融化时间提前,导致年冻融期缩短15.21%。应用本文建立的冻融多元线性回归模型计算得出,积温升高对研究区季节冻土退化的贡献率超过90%,是该区域季节冻土退化的最主要原因。[结论]在大兴安岭南段,冻土退化主要表现为冻融期缩短,气温升高是导致季节冻土退化的主要驱动因素,今后有必要监测季节冻土的变化,从而更好地进行森林经营。[Objective]Seasonal permafrost degradation directly changes water recharge at the beginning of the growing season,which in turn affects regional forest health.At present,the degradation of perma-frost in Southern Part of Greater Khingan Mountains is still unclear,especially the degradation characterist-ics under climate change.[Method]:In the long-term experimental forest of Saihanwula National Nature Reserve in Inner Mongolia,environmental factors such as air temperature,soil temperature,and volumet-ric soil water content were observed from 2014—2022 to analyze the characteristics of permafrost degrad-ation in forest seasons.[Result]:The temperature in Southern Part of Greater Khingan Mountains rose in shortly.The rise rate of annual average temperature was 0.42℃·(10 a)^(-1) in 1997-2022,which was larger 23.5%of the rate of 0.34℃·(10 a)^(-1) in 1973-1996,in Southern Part of Greater Khingan Mountains.It is particularly significant that the average temperature during the freeze-thaw period(i.e.,November to June)rose faster with the rate of 0.46℃·(10 a)^(-1).The freeze-thaw pattern of soil was characterized by top-down unidirectional freezing and unidirectional melting;The freezing rate and thawing rate became faster with in-creasing soil depth,reaching a maximum in the 40~80 cm soil layer(freezing rate 2.23 cm·d-1,thawing rate 4.50 cm·d^(-1)).Seasonally frozen soil continued to degrade,with the observed maximum freezing depth reduced from 80 cm to 40 cm.The freeze-thaw period was significantly shortened,the start of freezing was delayed,and the complete thaw time was advanced,resulting in a shortening of the annual freeze-thaw period by 15.21%.Applying the freeze-thaw multiple linear regression model established in this paper,the contribution of elevated air temperature accumulation to seasonal permafrost degradation in the study area was more than 90%.[Conclusion]:In the Southern Part of Greater Khingan Mountains,permafrost de-gradation is mainly characterized by shortening of the freeze-thaw period,

关 键 词：气候变化 季节性冻土 冻土退化 冻融期 

分 类 号：S714[农业科学—林学]