| 可可西里地区中更新世以来气候演化周期特征分析 |
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| 引用本文： | 田庆春,裴瑜,石培宏.可可西里地区中更新世以来气候演化周期特征分析[J].地理研究,2021,40(3):900-911. |
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| 作者姓名： | 田庆春 裴瑜 石培宏 |
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| 作者单位： | 山西师范大学地理科学学院,临汾041000;陕西师范大学地理科学与旅游学院,西安710119 |
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| 基金项目： | 国家自然科学基金项目(41701223) |
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| 摘 要： | 以青藏高原腹地可可西里地区为研究区,于2006年8月取得一湖泊沉积钻孔,进深106m,地理位置35°13′05″N,93°55′52.2″E,命名为BDQ06。选择湖泊沉积物粒度和总有机碳作为气候代用指标。基于古地磁建立的年代框架为基础,分析了可可西里地区929 kaBP以来古气候变化的周期特征。选择的分析方法为功率谱分析、小波分析和奇异谱分析。结果表明地球轨道三要素偏心率（100 ka）、地轴倾角（41 ka）和岁差（23 ka、19 ka）的准周期成分在BDQ06孔沉积中有明显反映,同时也包含84、66、54、36、31、27、17、15、12 、11.5、10 ka等周期成分。说明本区气候变化既受到轨道参数的影响,同时也与地球系统内部其它因素变化有关。小波分析和奇异谱分析显示不同气候周期既可在同一时段内叠加存在,又可在不同的时段内独立存在。780 kaBP左右古气候周期发生转型,在此之前以41 ka为主,同时也存在100 ka周期成分,之后以100 ka周期为主,但580 kaBP开始气候周期信号变得复杂,可能是受到青藏高原构造隆升的影响,导致水动力条件发生变化有关。
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| 关 键 词： | 可可西里 中更新世 气候变化 周期特征 |
| 收稿时间： | 2020-01-06 |
Characteristics of climate evolution cycle since the Middle Pleistocene in the Hoh Xil area |
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| TIAN Qingchun,PEI Yu,SHI Peihong.Characteristics of climate evolution cycle since the Middle Pleistocene in the Hoh Xil area[J].Geographical Research,2021,40(3):900-911. |
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| Authors: | TIAN Qingchun PEI Yu SHI Peihong |
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| Institution: | 1. College of Geographical Science, Shanxi Normal University, Linfen 041000, Shanxi, China2. School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China |
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| Abstract: | As one of the most important geological events in the Cenozoic era, the Tibetan Plateau's (TP) uplift has profoundly influenced the Asian and global climate and environmental evolution. Therefore, the TP has become the focus of geography research subject at home and abroad and has obtained great achievements. However, there are still many problems to be further explored. In this study, Hoh Xil, the hinterland of TP, was taken as the research area, and a 106-meter lake sedimentary borehole called BDQ06 was obtained in August 2006, geographically at 35°13′05″N and 93°55′52.2″E. The grain size and total organic carbon of lake sediments are chosen as climatic indicators. The approaches of Power Spectrum Analysis (PSA), Singular Spectrum Analysis (SSA), and the Continuous Wavelet Transform (CWT) are used to analyze the climate evolution cycle. Based on paleomagnetism's chronological framework, paleoclimatic cycle evolution since the last 929 ka has been investigated. The results show that the quasi-periodic components of the earth's eccentricity (100 ka), obliquity (41 ka), and precession (23 ka and 19 ka) exist in the BDQ06 hole. Meanwhile, the periodic components of 84, 66, 54, 36, 31, 27, 17, 15, 12, 11.5, 10 ka, and so on are found in the record. All this indicates that the climate changes in the Hoh Xil area are influenced not only by the earth's orbital parameters but also by other factors in the inner of the earth system. Furthermore, CWT and SSA show that different climate cycles can be superimposed in the same period and exist in different periods. Besides, an obvious climate transition has been observed at 780 ka. The dominant period is 41 ka though the period of 100 ka existed in the record ahead of this time point. However, after 780 ka, the controlling period shifted to 100 ka. Moreover, the climatic periodic characteristic has become gradually complicated since 580 ka BP, which is possibly affected by the change of hydrodynamic conditions caused by the TP's tectonic uplift. We concluded that although the Hoh Xil's climate cycle characteristics are consistent with global features, but they have apparent regional characteristics. Also, the periodic signals of grain size and total organic carbon are not wholly consistent, so the significance of climate proxy indicators needs to be further explored. |
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| Keywords: | Hoh Xil area Mid-Pleistocene climate change cycle characteristics |
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