Cold event at 8200 yr B.P. recorded in annually laminated lake sediments in eastern Europe
Cold event at 8200 yr B.P. recorded in annually laminated lake sediments in eastern Europe
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距今8200年的寒冷事件
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
A. Ojala
中科院分区：
文献类型：
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作者：
S. Veski;H. Seppä;A. Ojala
根据东欧爱沙尼亚每年层状湖泊沉积物序列进行的定量年平均温度重建表明，在8400- 8080年B. P.（=公元2000年之前）有一个明显的寒冷期;时间与格陵兰冰芯数据和西欧各种高分辨率记录中所见一致。在8250-8150年B. P.的最大冷却期间，爱沙尼亚的年平均气温比冷却前低2.0 °C，比冷却后低3.0 °C。花粉地层学和沉积学的数据表明，特别寒冷和多雪的冬季条件。冷事件的持续时间和幅度与北大西洋地表水突然变淡和随后的温盐环流扰动的模拟影响一致。假设这次冷事件是由从劳伦泰德冰盖融化到北大西洋的淡水脉冲引起的，则结果表明，至少在26°E以上，北大西洋海洋强迫与东欧气候之间存在着很强的遥相关，这可能是由纬向大气环流强度的变化所介导的。
A quantitative annual mean temperature reconstruction from an annually laminated lake-sediment sequence in Estonia, eastern Europe, shows a distinct cold period at 8400– 8080 yr B.P. (= before A.D. 2000); the timing is consistent with that seen in the Greenland ice-core data and various high-resolution records from western Europe. During maximal cooling at 8250–8150 yr B.P., the annual mean temperature in Estonia was ∼2.0 °C colder than prior to and ∼3.0 °C colder than after the cooling. The pollen-stratigraphic and sedimentological data suggest especially cold and snowy winter conditions. The duration and amplitude of the cold event agree with the modeled impact of a sudden freshening of the North Atlantic surface water and subsequent perturbation of the thermohaline circulation. Provided that the cold event was caused by a pulse of freshwater—from the melting Laurentide Ice Sheet—to the North Atlantic, the results indicate a strong teleconnection between the North Atlantic oceanic forcing and the east European climate at least up to long 26°E, mediated probably by the changing intensity of the zonal atmospheric circulation.