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首页> 外文期刊>Paleoceanography >Rapid switches in subpolar North Atlantic hydrography and climate during the Last Interglacial (MIS 5e)
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Rapid switches in subpolar North Atlantic hydrography and climate during the Last Interglacial (MIS 5e)

机译：上一次冰期间（MIS 5e）期间，北极亚极水文学和气候的快速变化

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At the peak of the previous interglacial period, North Atlantic and subpolar climate shared many features in common with projections of our future climate, including warmer-than-present conditions and a diminished Greenland Ice Sheet (GIS). Here we portray changes in North Atlantic hydrography linked with Greenland climate during Marine Isotope Stage (MIS) 5e using (sub)centennially sampled records of planktonic foraminiferal isotopes and assemblage counts and ice-rafted debris counts, as well as modern analog technique and Mg/Ca-based paleothermometry. We use the core MD03-2664 recovered from a high accumulation rate site (～34 cm/kyr) on the Eirik sediment drift (5726.34N, 4836.35W). The results indicate that surface waters off southern Greenland were ～3-5C warmer than today during early MIS 5e. These anomalously warm sea surface temperatures (SSTs) prevailed until the isotopic peak of MIS 5e when they were interrupted by a cooling event beginning at ～126 kyr BP. This interglacial cooling event is followed by a gradual warming with SSTs subsequently plateauing just below early MIS 5e values. A planktonic δ ~(18)O minimum during the cooling event indicates that marked freshening of the surface waters accompanied the cooling. We suggest that switches in the subpolar gyre hydrography occurred during a warmer climate, involving regional changes in freshwater fluxes/balance and East Greenland Current influence in the study area. The nature of these hydrographic transitions suggests that they are most likely related to large-scale circulation dynamics, potentially amplified by GIS meltwater influences.
机译：在前一个冰期间的高峰期，北大西洋和亚极气候与我们对未来气候的预测具有许多共同点，包括比现在暖和的条件和格陵兰冰盖（GIS）的减少。在这里，我们使用浮游有孔虫同位素的百年采样记录，组合计数和浮冰碎片计数以及现代模拟技术和Mg /来描绘与海洋同位素阶段（MIS）5e相关的北大西洋水文学与格陵兰岛气候相关的变化。基于钙的古温度计。我们使用从Eirik沉积物漂移（5726.34N，4836.35W）上的高堆积率站点（〜34 cm / kyr）回收的岩心MD03-2664。结果表明，在MIS 5e早期，格陵兰岛南部的地表水比今天温暖了约3-5℃。这些异常温暖的海表温度（SSTs）一直持续到MIS 5e的同位素峰为止，当它们被〜126 kry BP开始的冷却事件中断时。在此间冰期降温事件之后，逐渐变暖，SST随后稳定在MIS 5e早期值以下。降温过程中的最小浮游δ〜（18）O表示降温伴随着地表水明显清新。我们建议，在变暖的气候下，发生在极地回旋水文学中的切换，涉及淡水通量/平衡的区域变化以及研究区域的东格陵兰海流影响。这些水文过渡的性质表明，它们最有可能与大规模的环流动力学有关，可能会因GIS融水影响而放大。

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