近400年来塔克拉玛干沙漠南缘红柳沙包孢粉组合与古气候重建

发布时间：2018-03-02 09:42

  本文关键词： 塔克拉玛干沙漠南缘 策勒 红柳沙包 孢粉 气候　出处：《河北师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：策勒县位于新疆南疆塔克拉玛干沙漠南缘中段(35°17′~39°30′N,80°03′~82°10′E,平均海拔1380m),属于暖温带干旱荒漠气候,干燥度极高,可达20.8;日照时间较长,春夏多大风,多干热天气,沙尘暴频繁,植被种类组成极其贫乏,且植被群落类型单调、结构单一。本文通过对策勒县达玛沟地区红柳沙包剖面的孢粉组合特征研究,利用古气候定量重建方法(WAPLS方法),重建了研究区近400年来的气候变化过程,并探讨了植物群落的演替变化。研究结果显示,近400年来研究区气候和植被演化经历了3个主要阶段和9个次一级的气候波动。1590~1810年,是研究期内历时最长的一次以温暖干旱阶段,但伴有次一级的冷暖和干湿交替,其中包括1590~1650年和1731~1794年的偏湿期,1651~1730年和1795~1810年的偏干期。该阶段形成以蒿属、藜科、禾本科和柽柳科等植物为主的荒漠草原植被。气温为10.5~13.4℃,平均12.0℃,降水量为19.7~60.1mm,平均37.4mm。当时小冰期的低温条件和北大西洋涛动的负异常导致西风带位置南移、强度增强,使得到达研究区的水汽产生变化,促使该阶段的干旱时期相对较长。1811~1945年,是一个由暖干向冷湿的过渡期,气候波动较大,经历了明显的冷湿~冷干~冷湿~暖干的交替过程,其中1811~1838年和1859~1909年为两个冷湿期,1839~1858年,为一个冷干期;1910~1945年,是一个偏暖干期。本阶段植被条件有所改善,形成以柽柳、藜科等植物为主的荒漠灌丛植被,年平均气温为9.8~13.4℃,平均10.9℃,降水量为19.7~83.8mm,平均54.3mm;1946~2010年,气温小幅度下降,降水量明显增多,进入一个相对冷湿阶段,年均温为9.5~12.2℃,平均10.3℃,降水量为37.8~98.5mm,平均68.9mm。植被类型仍以荒漠灌丛为主。孢粉组合中出现大量以大禾本为主的农作物孢粉,人类活动对研究区气候环境影响逐渐增大。20世纪30年代以来,人工绿洲面积迅速扩大,明显的“绿洲效应”使区域气温小幅度下降,降水持续增加;20世纪70年代以后,降水呈现下降趋势。
[Abstract]:Cele County is located in the middle section of the southern edge of Taklimakan Desert in southern Xinjiang, with an average altitude of 1380mg. It is a warm temperate arid desert climate with a high degree of dryness of 20.8.The sunshine time is longer, the spring and summer are windy, the dry and hot weather is more dry and hot, and the sandstorm is frequent. The vegetation species composition is extremely poor, and the vegetation community type is monotonous and the structure is single. This paper studies the sporopollen assemblage characteristics of Hongliu Shabao section in Damagou area, Cele County, China. The paleoclimate quantitative reconstruction method WAPLS method was used to reconstruct the climate change process in the past 400 years in the study area, and the succession changes of plant communities were discussed. In the past 400 years, the climate and vegetation evolution in the study area has experienced three main stages and nine sub-level climatic fluctuations .1590 ~ 1810, which is the longest warm and arid stage in the study period, but accompanied by sub-level cold and warm, dry and wet alternations. It includes the dry periods of 1651 ~ 1730 and 1795 ~ 1730 in the wet period from 1590 to 1650 and from 1731 to 1794. The desert steppe vegetation is formed in this stage, which is dominated by Artemisia, Chenopodiaceae, Gramineae and Tamariaceae. The temperature is 10.50.13.4 鈩，

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