A 125-ka record of northern South American precipitation and the role of high-to-low latitude teleconnections
A 125-ka record of northern South American precipitation and the role of high-to-low latitude teleconnections
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DOI：
10.1016/j.quascirev.2021.107159
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发表时间：
2021-10
影响因子：
4
通讯作者：
A. Zhuravleva;Matthias Hüls;R. Tiedemann;H. Bauch
中科院分区：
文献类型：
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作者：
A. Zhuravleva;Matthias Hüls;R. Tiedemann;H. Bauch
格陵兰冰和次极地海洋沉积物岩芯中末次冰期温度的快速变化，即所谓的Dansgaard-Oeschger（D-O）循环，证明了这些北方纬度地区的区域气候紧密相连。相比之下，在D-O周期的高纬度到低纬度遥相关背后的过程不太清楚，由于交叉定年海洋和冰芯记录的不精确性和普遍缺乏坚实的多代理记录从热带地区。在这里，我们的目标是研究的热带海洋-大气系统的响应D-O变率，通过使用沉积物芯从加勒比海南部，位于热带辐合带（ITCZ）和大西洋纬向翻转环流（AMOC）的直接影响下。在D-O循环，在沉积的细粒陆源物质来源于奥里诺科河和亚马逊河的突变被确认。这些沉积物的变化与ITCZ的位置和AMOC强度的波动，通过其各自的影响，对水文气候的北方南美洲和强度的洋流提供河流物质的研究网站。稳定氧同位素数据进一步表明，在stadial事件期间，加勒比海东南部的上层海洋温度增加。由于这些变暖趋势与南极温度相关，它们似乎包含两极跷跷板和AMOC变化的印记，表明我们的核心位置受到两个半球普遍存在的过程的影响。
The occurrence of rapid last glacial temperature shifts in both Greenland ice and subpolar marine sediment cores, so-called Dansgaard-Oeschger (D-O) cycles, is evidence of a tight regional climate connectivity in these northern latitudes. By contrast, processes behind high-to-low-latitude teleconnections during the D-O cycles are less well understood, due to imprecisions in cross-dating marine and ice core records and a general lack of solid multi-proxy records from the tropical region. Here we aim to study the response of the tropical ocean-atmosphere system to D-O variability by using a sediment core from the southern Caribbean Sea, located under the direct influence of the Intertropical Convergence Zone (ITCZ) and the Atlantic meridional overturning circulation (AMOC). During D-O cycles, abrupt shifts in the deposition of fine-grained terrigenous material sourced from the Orinoco and Amazon rivers are recognized. These sedimentary changes were associated with fluctuations in both the ITCZ location and the AMOC strength through their respective influence on the hydroclimate of northern South America and strength of ocean currents delivering fluvial material to the study site. Stable oxygen isotope data further suggest increase in the upper ocean temperatures in the southeastern Caribbean Sea during stadial events. As these warming trends correlate with Antarctic temperatures, they seem to contain imprints of the bipolar seesaw and AMOC variability, demonstrating that our core location was influenced by processes prevalent in both hemispheres.