Ice-volume and insolation influences on hydroclimate changes in central eastern China during the antepenultimate glacial period
Ice-volume and insolation influences on hydroclimate changes in central eastern China during the antepenultimate glacial period
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DOI：
10.1007/s11430-021-9979-x
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发表时间：
2022-09
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影响因子：
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通讯作者：
Quan Wang;Shayue Yuan;Yijia Liang;Kan Zhao;Q. Shao;Zhenqiu Zhang;Junji Zhu;X. Kong;Yongjin Wang;Jianghu Lan;Hai Cheng;C. Xia;Yi Li
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作者：
Quan Wang;Shayue Yuan;Yijia Liang;Kan Zhao;Q. Shao;Zhenqiu Zhang;Junji Zhu;X. Kong;Yongjin Wang;Jianghu Lan;Hai Cheng;C. Xia;Yi Li
由于缺乏可靠的降水记录，东亚夏季风区域在轨道时间尺度上的降水变化一直存在争议。本文对中国中东部葫芦岛洞a230年代石笋的δ18O、δ13C、Sr/Ca和Mg/Ca进行了新的多代用记录。多代理记录重建了340 ~ 261kyr BP（距今1000年）的区域水文气候历史，大致覆盖了前次冰期。δ 18o记录以岁差周期为主，表明EASM在轨道时间尺度上响应北半球夏季日晒（NHSI）的变化。δ 13c、Sr/Ca和Mg/Ca的显著相关性表明，一个共同的因子即当地水循环控制了它们的变化，它们的主成分可以作为与区域降雨相关的代理。该复合记录与中国黄土高原的记录具有较好的相似性，显示出倒数冰期前降水逐渐减少的趋势，与全球冰量的变化一致。在长期趋势叠加上，3个相对湿润期对高NHSI期有响应，表明东亚地区降水变率是由全球冰量和NHSI的综合作用引起的。冰盖的增加和NHSI的降低导致经向温度梯度增大，西风带南移，缩短了梅雨和仲夏降水的持续时间。降水记录与石笋δ 18o记录的差异表明，后者代表了与季风环流相关的整体东亚季风强度，但不能直接反映洞穴遗址的降水变化。
The rainfall changes in East Asian summer monsoon (EASM) regions on the orbital timescale remain controversial due to the lack of reliable rainfall records. Here, we present new multiproxy records (δ18O,δ13C, Sr/Ca and Mg/Ca) of a230Th-dated stalagmite from Hulu Cave in central eastern China. Multiproxy records reconstruct a regional hydroclimate history from 340 to 261 kyr BP (thousand years before present), approximately covering the antepenultimate glacial period. Theδ18O record is dominated by the precessional cycles, suggesting that EASM responds to changes in Northern Hemisphere summer insolation (NHSI) on the orbital timescale. Significant correlations amongst theδ13C, Sr/Ca and Mg/Ca suggest that a common factor, i.e., the local hydrological cycle, controlled their variability, and their leading principal component can be used as a proxy linked to regional rainfall. This composite record bears a good similarity to those from the Chinese Loess Plateau, showing a gradually decreasing rainfall during the antepenultimate glacial period, consistent with changes in global ice volume. Superimposed on the long-term trend, three relative wetter intervals were responding to the higher NHSI periods, suggesting that EASM rainfall variability was induced by integrated effects of global ice volume and NHSI. The increased ice sheets and lower NHSI resulted in an increased meridional temperature gradient and southward shift of the westerlies, which shortened the duration of Meiyu and midsummer rainfall. The differences between the rainfall record and the stalagmiteδ18O record indicate that the latter represents the overall EASM intensity linked to monsoon circulation, but does not directly reflect the rainfall changes at the cave sites.