%0 Journal Article
%T MAXIMUM TEMPERATURE RECONSTRUCTION FOR ANIMAQING MOUNTAINS OVER PAST 830 YEARS BASED ON TREE-RING RECORDS<br>树轮记录的阿尼玛卿山区过去 830年夏半年最高温变化*
%A Gou Xiaohua
%A Yang Meixue
%A Peng Jianfeng
%A Zhang Yong
%A Chen Tuo
%A Hou Zongdong
%A <br>勾晓华
%A 杨梅学
%A 彭剑峰
%A 张永
%A 陈拓
%A 侯宗东
%J 第四纪研究
%D 2006
%I 
%X Due to the weakness of ecological systems caused mainly by enhanced human activities as well as regional climate changes, the ecological environment in the Yellow River source region is seriously deteriorated. To examine the reasons and mechanism of ecological environment changes in the region, its history should be understood first. Dendroclimatology is one of the important methods for examining the past global climate changes and the tree ring data was used widely as an important archive in paleoclimatic research because of its precise dating, annual resolution, and high correlations with instrumental climate data. Based on tree-ring width and/or density chronologies, long-time-scale climate variations have been reconstructed on both regional and hemispheric spatial scales. The study area, the Animaqing Mountains is located within the Yellew River source region. Cypress (Juniperus prezewalskii) tree-ring cores were taken from living trees from the Animaqing Mountains. Samples were cross-dated with three methods: skeleton-plot cross-dating, visual cross-dating of the ring-width measurement series, and testing of cross-dating using the computer program COFECHA. The oldest tree was sampled as 1532 years old. The cross-dated tree-rings were measured on a Velmex tree-ring width measuring system ( 0.001mm). The computer program ARSTAN was used to develop the chronology. Most tree-ring series were detrended with negative exponential curves or straight line that conforms to the expected biological growth trend model. Few of those that did not fit the negative exponential curves or straight line were standardized using a 67 % smoothing spline. A tree-ring chronology of 830 (1172~2001) years was developed. Before 1172, the expressed population signal (EPS) of the chronology is lower than the recommended threshold of 0.85 because the sample depth is insufficient. The analysis demonstrates that the tree-ring index is correlated negatively with the summer half year (April to September)average maximum temperature significantly.The maximum temperature of the research area was reconstructed based on the correlation analysis model. Test results confirmed the validity of our regression model. The reconstruction contains lots of high frequency signals as well as low frequency trends. The study region has been experienced three significant cooling periods in the past 830 years. One of the cooling periods is during 1820s~1900s, while the global warming is significant. However, the analysis showed that the warming periods are much shorter than the cooling period. While warming speed is higher than cooling, it could lead to severe droughts in the research region. Several warm periods reconstructed coincide with severe droughts that recorded by other archives.
%K Yellow River source region
%K tree-ting
%K chronology
%K maximum temperature
%K reconstruction<br>黄河源区
%K 树木年轮
%K 宽度年表
%K 最高温
%K 重建
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=EA07051745CDC8D89D5F01A3A4CFE6A9&aid=6E85CFBD4629F094&yid=37904DC365DD7266&vid=96C778EE049EE47D&iid=B31275AF3241DB2D&sid=243DE6042D93E88B&eid=EAA944F99AA73B33&journal_id=1001-7410&journal_name=第四纪研究&referenced_num=14&reference_num=44