Topography's crucial role in Heinrich Events.
Topography's crucial role in Heinrich Events.
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地形在海因里希事件中起着至关重要的作用。
DOI：
10.1073/pnas.1414882111
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发表时间：
2014
影响因子：
11.1
通讯作者：
Roberts WH
中科院分区：
文献类型：
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作者：
Roberts WH
海因里希事件是劳伦蒂德冰盖的突然变化，导致了观测充分的海因里希层的出现，被认为对全球气候有很大的影响。大多数关注气候对这些事件的反应的研究的重点一直是冰山融化产生的淡水通量。然而，冰盖高度的变化可能会迫使气候发生变化。在这项研究中，我们介绍了一个新开发的气候/冰盖耦合模式的结果，以显示这种地形变化本身以及与冰山融化的淡水通量相一致的影响。我们发现地形强迫可以解释在海因里希事件期间观察到的一些气候变化，例如佛罗里达的变暖和增湿以及北大西洋中部温暖的海面温度，而单靠淡水强迫是不能解释的。我们还发现了一些地区，例如热带大西洋，那里的反应是两者的混合：在这里，观察可能有助于理清每一种机制的相对重要性。这些结果表明，海因里希事件通过向北大西洋输入淡水而导致气候变化的简单范例需要修改。
Heinrich Events, the abrupt changes in the Laurentide Ice Sheet that cause the appearance of the well-observed Heinrich Layers, are thought to have a strong effect on the global climate. The focus of most studies that have looked at the climate’s response to these events has been the freshwater flux that results from melting icebergs. However, there is the possibility that the varying height of the ice sheet could force a change in the climate. In this study, we present results from a newly developed coupled climate/ice sheet model to show what effect this topographic change has both on its own and in concert with the flux of freshwater from melting icebergs. We show that the topographic forcing can explain a number of the climate changes that are observed during Heinrich Events, such as the warming and wettening in Florida and the warm sea surface temperatures in the central North Atlantic, which freshwater forcing alone cannot. We also find regions, for example the tropical Atlantic, where the response is a mixture of the two: Here observations may help disentangle the relative importance of each mechanism. These results suggest that the simple paradigm of a Heinrich Event causing climate change via freshwater inputs into the North Atlantic needs to be revised.