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巴丹吉林沙漠南缘191 a来年降水量重建及初步分析 被引量:9
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作者 张永香 於琍 尹红 《沙漠与绿洲气象》 2015年第1期12-16,共5页
沙漠及其边缘地区生态环境脆弱,对气候变化敏感。但沙漠地区有限的森林资源限制了区域百年到千年尺度上的历史气候变化研究。利用采自巴丹吉林南缘的青海云杉年轮宽度资料,重建了区域近191 a(1815—2005年)来的年降水(前一年7月至当年8... 沙漠及其边缘地区生态环境脆弱,对气候变化敏感。但沙漠地区有限的森林资源限制了区域百年到千年尺度上的历史气候变化研究。利用采自巴丹吉林南缘的青海云杉年轮宽度资料,重建了区域近191 a(1815—2005年)来的年降水(前一年7月至当年8月的总降水量)变化序列。重建的相关系数是0.636,方差解释量为40.4%,调整自由度后的解释方差R2adj为0.392。重建结果稳定可靠。分析区域过去年降水变化结果可见,19世纪该区域干湿变化频繁,20世纪前半段主要以干旱为主,干湿转变较少。20世纪20年代的干旱事件在巴丹吉林南缘的干旱持续时间更长。周期分析的结果表明,区域年降水量变化有2 a、4 a、64 a等周期。 展开更多
关键词 巴丹吉林沙漠南缘 树木 年降水量重建
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A novel procedure for pollen-based quantitative paleoclimate reconstructions and its application in China 被引量:9
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作者 CHEN JianHui LV FeiYa +10 位作者 HUANG XiaoZhong H.John B.BIRKS Richard J.TELFORD ZHANG ShengRui XU QingHai ZHAO Yan WANG HaiPeng ZHOU AiFeng HUANG Wei LIU JianBao WEI GuoYing 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第11期2059-2066,共8页
Traditionally, the evaluation of pollen-based quantitative paleoclimate reconstructions focuses on the ability of calibration sets to infer present climatic conditions and/or the similarity between fossil and modem as... Traditionally, the evaluation of pollen-based quantitative paleoclimate reconstructions focuses on the ability of calibration sets to infer present climatic conditions and/or the similarity between fossil and modem assemblages. Objective criteria for choosing the most appropriate climate parameter(s) to be reconstructed at a specific site are thus lacking. Using a novel approach for testing the statistical significance of a quantitative reconstruction using random environmental data, in combination with the advantageous large environmental gradients, abundant vegetation types and comprehensive modem pollen databases in China, we describe a new procedure for pollen-based quantitative paleoclimatic reconstructions. First, the most significant environmental variable controlling the fossil pollen assemblage changes is identified. Second, a calibration set to infer changes in this targeted variable is built up, by limiting the modem ranges of other environmental variables. Finally, the pollen-based quantitative reconstruction is obtained and its statistical significance assessed. This novel procedure was used to reconstruct the mean annual precipitation (Pann) from Gonghai Lake in the Lvliang Mountains, and Tianchi Lake in the Liupan Mountains, on the eastern and western fringe of the Chinese Loess Plateau, respectively. Both Pann. reconstructions are statistically significant (p〈0.001), and a sound and stable correlation relationship exists in their common period, showing a rapid precipitation decrease since 3300 cal yr BP. Thus, we propose that this procedure has great potential for reducing the uncertainties associated with pollen-based quantitative paleoclimatic reconstructions in China. 展开更多
关键词 POLLEN Quantitative reconstructions Statistical significance Marginal areas of the Asian summer monsoon
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