| 青藏高原地区过去2000年来的气候变化 |
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| 引用本文： | 杨保.青藏高原地区过去2000年来的气候变化[J].地球科学进展,2003,18(2):285-291. |
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| 作者姓名： | 杨保 |
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| 作者单位： | 中国科学院寒区旱区环境与工程研究所,甘肃,兰州,730000 |
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| 基金项目： | 国家自然科学基金项目"青藏高原过去2千年气候变化与气候模拟研究"(编号:40201011),中国科学院知识创新工程重大项目"西部生态环境演变规律与水土资源可持续利用研究"第二课题"近2000年来西部环境变化研究"(编号:KZCX1 10 02)联合资助 |
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| 摘 要： | 依据冰芯、树轮、沉积物分析和冰川波动等各单点古气候代用资料,以及重建的综合温度变化曲线,分析了近 2000年青藏高原温度变化的整体性和区域性特征。全青藏高原综合温度曲线显示中世纪暖期（1150-1400年）、小冰期（1400-1900年）以及公元 3～5世纪冷期的存在。青藏高原温度变化具有明显的区域性特征。在 9～11世纪,青藏高原东北部以温暖为特征,而青藏高原南部和西部表现为寒冷。青藏高原南部和西部分别于1150-1400年（此时段在高原东北部表现为弱暖期）和1250-1500年经历了气候变暖。与中国东部文献记录的最新综合研究结果比较,高原东北部与中国东部的温度变化最为一致。而且,许多重大气候事件,如1100-1150年、1500-1550年、1650-1700年和1800-1850年的冷事件在高原和中国东部同时出现,而后 3次冷期与小冰期期间中国西部发生的冰川前进相匹配。
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| 关 键 词： | 青藏高原 近2000年 温度变化 冰芯、树轮和沉积物 冰川波动 |
| 文章编号： | 1001-8166(2003)02-0285-07 |
| 收稿时间： | 2002-02-20 |
| 修稿时间： | 2002年2月20日 |
CLIMATE HISTORY OF THE TIBETAN PLATEAU DURING THE LAST TWO MILLENNIA |
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| Yang Bao.CLIMATE HISTORY OF THE TIBETAN PLATEAU DURING THE LAST TWO MILLENNIA[J].Advance in Earth Sciences,2003,18(2):285-291. |
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| Authors: | Yang Bao |
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| Institution: | Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China |
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| Abstract: | The reconstruction of long climatic series spanning the past few centuries and millennia is important both for understanding natural climate variations at those timescales and for estimating anthropogenic influence on the climate system. Our view of past climatic conditions, however, is heavily biased by the data from high-latitude northern and southern hemispheres. To test and validate climatic models on a global scale, it is essential to expand this database to all regions of the Earth’s surface. The Tibetan plateau affects the large-scale atmospheric circulation over Asia including the monsoon over South Asia and the south China sea. Therefore, the climate history of the Tibetan plateau is an important component in reconstructing the Earth's climate history. In the last decades, many paleoclimatic records, such as ice cores, tree rings, lake sediments and glacier fluctuations covering the last two millennia, have been recovered on the Tibetan plateau. In this paper, the above various proxy data are used to reconstruct the regional-scale temperatures of the Tibetan plateau during the last two millennia. The reconstructions display temperature fluctuations in different parts of the Tibetan plateau. Generally, the northeastern Tibetan plateau experienced distinct warming in 800-1100 AD, slight warming in 1150-1350 AD, and three cold periods during the “Little Ice Age” between 1400-1900 AD. In contrast, the southern Tibetan plateau witnessed an early warming in the6-8th centuries, an obvious cooling in 800-1150 AD, a dramatic warming in1150-1400 AD, and the coldest conditions in the 17th century. In addition, the warmer and cooler periods correspond well to glacier fluctuations in the northeastern and southern Tibetan plateau. For the western Tibetan plateau, the δ18O records of the Guliya ice core indicate that the temperatures in the “Little Ice Age” were higher than that in the middle ages, which would contrast with all other regions of the plateau. On the other hand, a 1400-year-long tree-ring chronology established in the northwest Karakorum, Pakistan, shows that the warmest period was from 800 AD and 1139, whereas an obvious cool period was recorded in 1140-1874 AD with the coldest period in the first half of the 17th century. More proxy records from the western Tibetan plateau are needed to arrive at firm conclusions.
A number of lines of evidence suggested that the “Medieval Warm Period” was not global in extent, although relatively warm conditions might have prevailed during some parts of the middle ages for some areas of the globe. As described above, in China, the warm climate during this period varied in time and space. Evidence from Dunde, Dulan, Tianjun, Qinghai lake, and other independent proxy records indicates that a warm period between 800 AD and 1100 AD occurred in the northeastern Tibetan Plateau and eastern China, which was also indicated by tree-ring chronology in the Karakorum. Five lines of evidence (Qamdo, Ximen lake, Hidden lake, Chencou lake, and the southern Tibet records)indicate that the southern Tibetan plateau experienced a warm period in 1150-1400 AD, which was also recorded in the temperature reconstructions for the whole plateau. Therefore, the two warm periods of 800-1100 AD and 1150-1400 AD can be referred to as correlative of the “Medieval Warm Period”, regardless of their regional differences. Several circulation patterns-winter monsoon, west wind drift, and summer monsoon (south-west and south-east monsoon), might have been responsible for these regional temperature differences. |
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| Keywords: | Tibetan plateau Climate change The last two millennia Ice core Tree ring Lake sediments Glacier fluctuations |
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