High-resolution record of Northern Hemisphere climate extending into the last interglacial period
High-resolution record of Northern Hemisphere climate extending into the last interglacial period
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DOI：
10.1038/nature02805
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发表时间：
2004-09-09
期刊：
影响因子：
64.8
通讯作者：
White, JWC
中科院分区：
文献类型：
--
作者：
Andersen, KK;Azuma, N;White, JWC
20世纪90年代在格陵兰岛中部钻探的两个深冰芯在北半球气候重建中发挥了关键作用，但由于基岩附近的冰折叠，最古老的冰芯段在年代学上受到了干扰。在这里，我们展示了北格陵兰冰芯的未受干扰的气候记录，该冰芯可以追溯到现在之前的12.3万年前，也就是最后一次间冰期。冰层中的氧同位素表明，上一次间冰期气候稳定，气温比今天高5摄氏度。我们发现格陵兰北部的新记录与格陵兰中部未受干扰的岩心部分之间存在着出人意料的巨大温差，这表明北半球的冰范围调整了格陵兰的纬度温度梯度。这一记录表明，标志着上一次冰川时期开始的气温缓慢下降。我们的记录显示，大约115,000年前，在冰川条件完全发育之前，由突然的气候变暖引发了一个迄今未被认识到的暖期。这次事件似乎没有直接的南极对应事件，这表明两个半球之间的气候拉锯战(主导上一次冰川时期)在这个时候没有运行。
Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5 degreesC warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time.