树轮稳定氧同位素重建东大山过去205年来水汽压变化  

Vapor pressure variations reconstructed by tree-ring stable oxygen isotopes in Dongda Mountain during the past 205 years

作　　者：李强[1,2,3] 邓若兰[4,1] 刘若时 刘禹 LI Qiang;DENG Ruolan;LIU Ruoshi;LIU Yu(State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,China;CAS Center for Excellence in Quaternary Science and Global Change,Xi’an 710061,China;Joint Center for Global Change Studies(JCGCS),Beijing 100875,China;Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region,School of Water and Environment,Chang’an University,Xi’an 710054,China;Department of Environmental Science and Technology,School of Human Settlements and Civil Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710061 [2]中国科学院第四纪科学与全球变化卓越创新中心,西安710061 [3]全球变化研究协同创新中心,北京100875 [4]长安大学水利与环境学院旱区地下水文与生态效应教育部重点实验室,西安710054 [5]西安交通大学人居环境与建筑工程学院环境科学与技术系,西安710049

出　　处：《地球环境学报》2020年第6期639-647,共9页Journal of Earth Environment

基　　金：国家自然科学基金项目(41873021,U1803245,41991251);中国科学院青年创新促进会(2017451);中国科学院“西部之光”(西部青年学者A类);黄土与第四纪地质国家重点实验室培育基金。

摘　　要：对采自河西走廊东大山的青海云杉(Picea crassifolia)树轮样本提取纤维素并测定其稳定氧同位素比率(δ^(18)O),建立过去205年来树轮δ^(18)O年表序列。与观测数据相关分析发现树轮δ^(18)O年表与周边7—8月平均水汽压具有显著的负相关关系(r=−0.643,n=59,p<0.001),因此重建了河西走廊东大山周边过去205年的7—8月平均水汽压变化序列,重建方程方差解释量达41.4%,分段检验表明水汽压重建结果稳定可靠。在重建的205年中,水汽压力偏大阶段有6个,偏低阶段有7个。该重建序列与周边地区的水文气候重建的干湿阶段变化及西北地区极端干旱历史事件具有一定的同步性,并可代表大区域范围水汽压变化,进一步证明了本文重建序列的准确性。空间相关分析结果暗示研究区7—8月水汽主要受亚洲季风影响,同时伴有少量西风水汽传输。Background,aim,and scope Due to the global warming,the regional climate and hydrological processes are undergoing the major changes,the surface water vapor pressure in the northwest arid region is closely related to the water vapor content and precipitation.The water vapor is the most active component in the global water cycle processes.It is of great significance to grasp the facts and laws of water vapor pressure change for understanding the regional water circulation process and its response to the global change.However,the recording history of the instrumental data is too short to be used in the study of long-time scale climate change.The tree rings have an incomparable advantage in the study of past climate change in the arid areas.This study is intended to provide the research data of tree rings in the Dongda Mountain of Hexi Corridor,the facts of regional climate change are revealed,the basic data are provided for understanding the causes of climate change in the northwestern China,and the scientific reference is provided for the utilization of water resources in the arid areas.Materials and methods The total 66 sample cores of 39 Picea crassifolia were collected in the Dongda Mountain nature reserve of Hexi Corridor(39°00′—39°04′N,100°45′—100°51′E)in April 2012.After the sample core is air-dried,the cross dating is carried out and the width chronology is established,the quality of dating is inspected by use of the COFECHA program.On the basis of the exact dating,the 4—5 sample cores with wider rings and fewer missing rings are selected for stripping year by year.The stripped sample is moved to the filter tube for the organic solvent extraction;subsequently,the sodium hypochlorite and acetic acid are used to remove the lignin;the sodium hydroxide solution is used to remove the hemicellulose;finally,the samples is homogenized by the ultrasonic cell crushing apparatus,and then it is dried and preserved after the freeze-drying in vacuum,so theα-cellulose is obtained.The cellulose samples is

关 键 词：树轮δ18O 水汽压重建 东大山 青海云杉 

分 类 号：S791.18[农业科学—林木遗传育种] P467[农业科学—林学]