On the triggering mechanism of Heinrich events
On the triggering mechanism of Heinrich events
复制标题
海因里希事件的触发机制研究
DOI：
10.1073/pnas.1116575108
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
G. Ramstein
中科院分区：
文献类型：
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作者：
J. Alvarez;G. Ramstein
尽管对海因里希事件由劳伦蒂德内部冰盖振荡产生的经典解释有一些不足之处，但它的简单性使其得以存在20年。然而，最近的文章终于揭开了海因里希事件是如何引发的谜团。在PNAS中，Marcott等人。(2)报道的来自西北大西洋的镁/钙数据显示，在海因里希事件发生前1000多年，伴随着大规模的次表层变暖的大西洋子午线翻转环流(AMOC)减速。事实上，问题的症结在于海洋的次表层。由于最近在南极洲周围的观察，人们对海洋和冰盖动力学之间鲜为人知的耦合效应已被揭示为理解过去大规模冰山清洗的关键。通过这种方式，观测到的海洋变暖对冰流系统施加的控制(3)，再加上AMOC减速(4)和大的次表层变暖(2)的确认预期，清楚地表明了海因里希事件的气候先兆。因此，该场景可以总结如下(图1说明了专门针对Heinrich事件1的机制)：
Although the classic interpretation of Heinrich events being produced by internal Laurentide ice-sheet oscillations (1) had some deficiencies, its simplicity permitted it to survive 2 decades. However, recent articles finally shed light on the mystery of how Heinrich events are triggered. In PNAS, Marcott et al. (2) reported Mg/Ca data from the northwest Atlantic Ocean revealing an AMOC (Atlantic meridional overturning circulation) slowdown accompanied by a large subsurface warming that occurred more than 1,000 years before Heinrich events. The crux, indeed, resided in the subsurface of the ocean. Thanks to recent observations around Antarctica, the poorly understood coupled effects between ocean and ice-sheet dynamics have been revealed to be crucial for understanding past massive iceberg purges. In this way, the observed control that a warming ocean exerts on the ice-streams regime (3), combined with the confirmed anticipation of an AMOC slowdown (4) and a large subsurface warming (2), clearly indicates a climatic precursor for Heinrich events. The scenario can thus be summarized as follows (Fig. 1 illustrates the mechanism specifically for Heinrich event 1):