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
孙逸晨 1魏江生 2舒洋 3赵鹏武 4齐桂萍 5张静6
作者信息
- 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;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
- 2. 内蒙古农业大学草原与资源环境学院,内蒙古呼和浩特 010011;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;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
- 3. 内蒙古农业大学林学院,内蒙古呼和浩特 010019
- 4. 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;内蒙古农业大学林学院,内蒙古呼和浩特 010019
- 5. 内蒙古赤峰市青山林场,内蒙古赤峰 024200
- 6. 内蒙古赤峰市赛罕乌拉自然保护区管理局,内蒙古赤峰 025150
- 折叠
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.
Abstract
[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,and warmer temperatures are the main driver of seasonal permafrost degradation,making it necessary to monitor changes in seasonal permafrost in the future for better forest management.
关键词
气候变化/季节性冻土/冻土退化/冻融期Key words
climate change/seasonal permafrost/permafrost degradation/freeze-thaw period引用本文复制引用
基金项目
国家重点研发计划(2022YFF0801801)
国家自然科学基金(42230503)
出版年
2024
国家科技期刊平台
NSTL
万方数据