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首页> 外文学位 >A multi-proxy study of planktonic foraminifera to identify past millenial-scale climate variability in the East Asian Monsoon and the Western Pacific Warm Pool (Globigerinoides ruber, Globigerinoides sacculifer, Neogloboquadrina dutertrei, Globorotalia crassaformis).
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A multi-proxy study of planktonic foraminifera to identify past millenial-scale climate variability in the East Asian Monsoon and the Western Pacific Warm Pool (Globigerinoides ruber, Globigerinoides sacculifer, Neogloboquadrina dutertrei, Globorotalia crassaformis).

机译：一项关于浮游有孔虫的多代理研究，旨在确定东亚季风和西太平洋暖池（千球藻，球果球藻，新球藻dtertrei，球孢藻）的过去千年尺度的气候变化。

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High resolution paleo-climatological data from IMAGES core MD97-2141 (8.80°N, 121.31°E) located in the Sulu Sea within the western tropical Pacific reveal the first evidence of continuous millennial-scale variability in surface ocean conditions over the last 150,000 years. The millennial-scale planktonic foraminiferal oxygen isotope (δ18O) oscillations of Globigerinoides ruber (G. ruber) between 30,000–65,000 years (MIS3) are apparently in-phase with the Greenland ice core record and have amplitudes 1/3 to 2/3 the size of the Sulu Sea glacial-interglacial δ 18O amplitude of 1.3‰. In the same interval variations in planktonic foraminiferal Mg/Ca suggest that millennial-scale sea surface temperature (SST) variations were small (0.6–1°C) and out-of-phase with δ 18O indicating that δ18O variability was mainly driven by changes in surface water salinity. This result implies that the linked East Asian monsoon and the western Pacific Intertropical Convergence Zones, both influencing the Sulu Sea, have fluctuated on the same millennial time scale as higher latitude climatic systems.; To further investigate the origin of the MIS3 δ18O G.ruber variations, the relative abundance of all planktonic foraminifer species and the δ18O values of four planktonic foraminifer species was determined during MIS3. Combined, these data provide a detailed reconstruction of changes in the western tropical Pacific thermocline structure. The δ18O composition of the mixed-layer foraminifera (G. ruber and Globigerinoides sacculifer) and upper thermocline species (Neogloboquadrina dutertrei) displays poor similarity with the δ18O of the sub-thermocline dweller Globorotalia crassaformis. δ18O G.crassaformis shows larger δ18O variations (∼1‰) than the surface dwellers indicating past fluctuations in the influence of high salinity North Pacific Tropical Waters that currently enter the Sulu Sea across the Mindoro Strait during the months of the winter monsoon. The faunal and isotopic data suggest a switch from winter to summer monsoon predominance after 55 kyr. However this predominance is interrupted by at least three episodes of increased winter monsoon between 42–46 kyr.; Comparison of the proxy SST and planktonic foraminiferal δ 18O profiles for the last glacial/interglacial sequence from fourteen cores in tropical and subtropical oceanic settings indicates that termination I in δ18O coincides with SST change at some sites, while δ 18O lags SST by 3,000 years at other locations. A comparison of SST and δ18O shows a linear increase in SST from glacial to interglacial conditions. Sites where SST is leading the δ 18O record indicate fresher conditions during the LGM, and these sites are all located in areas influenced by increased atmospheric water vapor during times of today's La Niña.
机译：来自位于热带西太平洋苏禄海的IMAGES核心MD97-2141（8.80°N，121.31°E）的高分辨率古气候数据揭示了过去15万年来表层海洋状况连续千年尺度变化的初步证据。 。在30,000至65,000年之间（MIS3）的千禧级浮游有孔虫氧同位素（δ 18 O）振荡（italic> Globigerinoides ruber （ G.ruber ）振荡）明显与格陵兰冰芯记录同相，其振幅为苏禄海冰间冰期δ 18 O振幅1.3‰的1/3至2/3。在相同的时间间隔内，浮游有孔虫的Mg / Ca的变化表明，千年尺度海表温度（SST）的变化很小（0.6-1°C），并且与δ 18 O呈异相δ 18 O的变化主要是由地表水盐度的变化引起的。这一结果表明，影响苏禄海的东亚季风和太平洋西太平洋热带辐合带的联系，在与高纬度气候系统相同的千年尺度上波动。为了进一步研究MIS3δ 18 O G.ruber 变异的起源，所有浮游有孔虫种类的相对丰度和δ 18 O值。综合起来，这些数据提供了对热带西太平洋温跃层结构变化的详细重建。混合层有孔虫（ G。ruber 和 Globigerinoides sacculifer ）和上温跃层物种（ Neogloboquadrina dutertrei）的δ 18 O组成与亚热线居民 Globorotalia crassaformis 的δ 18 O相似性较差。 δ 18 O G.crassaformis 的δ 18 O变化（〜1‰）比地面居民更大高盐度的北太平洋热带水域过去的波动，目前在冬季季风的几个月中穿过明多洛海峡进入苏禄海。动物和同位素数据表明，在55年后，冬季风从夏季风转变为夏季风。但是，这种优势至少被42-46年间冬季季风增加至少三集所打断。比较热带和亚热带海洋环境中14个岩心的末次冰川/冰间层序列的代用SST和浮游有孔虫δ 18 O剖面，表明δ 18 O处的终止I与某些站点的海表温度变化吻合，而δ 18 O在其他站点与海表温度相比滞后了3,000年。 SST和δ 18 O的比较表明，从冰期到冰间期，SST呈线性增加。 SST领先δ 18 O记录的地点表明在LGM期间天气较新，这些地点都位于当今拉尼娜时期受大气水汽增加影响的区域。

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