Modelled atmospheric temperatures and global sea levels over the past million years
Modelled atmospheric temperatures and global sea levels over the past million years
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DOI：
10.1038/nature03975
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发表时间：
2005-09-01
期刊：
影响因子：
64.8
通讯作者：
Oerlemans, J
中科院分区：
文献类型：
--
作者：
Bintanja, R;van de Wal, RSW;Oerlemans, J
海洋沉积物氧同位素组成的记录表明，在过去的百万年中，地球的气候经历了一系列的冰期和间冰期。但是氧同位素记录的解释是复杂的，因为冰盖中的同位素储存和深水温度都会影响记录的同位素组成（1-5）。要区分这两种影响，需要对海平面或深海温度进行长期记录，而目前还没有这种记录。在这里，我们使用了一个北方冰盖（6）和海洋温度的耦合模型，被迫匹配从57个全球分布的沉积物岩心中汇编的过去百万年的氧同位素记录，以同时量化两者的贡献。我们发现，冰盖的贡献变化的氧同位素组成的变化从10%的冰期开始到60%的冰川最大，这表明强大的海洋冷却之前缓慢的冰盖建设。该模型产生相互一致的时间序列的大陆平均表面温度之间的40和80度N，冰量和全球海平面。我们发现，在极端冰川阶段，气温比现在低17 +/- 1.8摄氏度，海平面120 +/- 10米相当于大陆冰。
Marine records of sediment oxygen isotope compositions show that the Earth's climate has gone through a succession of glacial and interglacial periods during the past million years. But the interpretation of the oxygen isotope records is complicated because both isotope storage in ice sheets and deep-water temperature affect the recorded isotopic composition(1-5). Separating these two effects would require long records of either sea level or deep-ocean temperature, which are currently not available. Here we use a coupled model of the Northern Hemisphere ice sheets(6) and ocean temperatures, forced to match an oxygen isotope record for the past million years compiled from 57 globally distributed sediment cores, to quantify both contributions simultaneously. We find that the ice-sheet contribution to the variability in oxygen isotope composition varied from ten per cent in the beginning of glacial periods to sixty per cent at glacial maxima, suggesting that strong ocean cooling preceded slow ice-sheet build-up. The model yields mutually consistent time series of continental mean surface temperatures between 40 and 80 degrees N, ice volume and global sea level. We find that during extreme glacial stages, air temperatures were 17 +/- 1.8 degrees C lower than present, with a 120 +/- 10 m sea level equivalent of continental ice present.