Comprehensive analysis of Atlantic Circulation during Heinrich-Event 1 & 2

大西洋经向翻转环流（AMOC）是全球气候系统的重要组成部分。它对热量和碳从表层到深海的再分配以及从深海到表层的再分配有着至关重要的影响。因此，评估AMOC的敏感性是古气候学的一个重大挑战。这里的重点是如何通过大陆冰融化过量的淡水输入可以影响其翻转的活力，因此，热量供应到高北方纬度。这种强迫可以通过调查其在末次冰期极端冰山排放事件（所谓的海因里希事件）期间进入开放的北大西洋的行为来测试。近年来，大量的海洋沉积物中231 Pa/230 Th的测量结果表明，该示踪剂在海洋沉积物中的应用对海洋有机碳自然变化的重建具有重要价值。在这个项目中，我们测量Pa/Th在众多的沉积物芯在海因里希事件1和2，从而大大增强了现有的数据库的Pa/Th的调查大西洋深环流研究。在进行这些测量的同时，还测定了沉积物样品中的生物蛋白石含量。在Heinrich-Event 1和2之前、期间和之后的AMOC的强度和几何形状可以以逆模型方法从该新数据库导出。通过这一点，我们的目标是回答这个问题，如果海因里希事件要么导致AMOC的中止，或者如果相反，海因里希事件是AMOC变化的结果。因此，在潜在的冰盾融化和降水增加的背景下，在北大西洋北方，海因里希事件可能会显示一个模型的情况下，提高我们的理解即将到来的AMOC对气候变化的反应。

The dynamic of the Atlantic Meridional Overturning Circulation (AMOC) is one of the key players in the global climate system. It crucially influences the redistribution of heat and carbon from surface into the deep sea and vice versa. Therefore, assessing the sensitivity of the AMOC is a major challenge for paleoclimatology. Here the focus is set on how excessive freshwater input through melting of continental ice can affect its overturning vigour and, hence, heat supply to high northern latitudes. Such forcing can be tested by investigating its behaviour during extreme iceberg discharge events into the open North Atlantic during the last glacial period, so called ¿Heinrich-Events¿. In recent years numerous studies have provided a wealth of 231Pa/230Th measurements in marine sediments, successfully demonstrating the important value of this tracer for the reconstruction of the natural variability of the AMOC. In this project we measure Pa/Th in numerous sediment cores across Heinrich events 1 and 2 thus strongly augmenting the available database of Pa/Th for the investigation of the Atlantic Ocean deep circulation studies. These measurements are accompanied by the determination of the biogenic opal content of the sediment samples. Strength and geometry of the AMOC before, during and after the Heinrich-Events 1 and 2 can be derived from this new database in an inverse model approach. By this we are aiming for answering the question if Heinrich-Events either caused cessations of AMOC or if maybe in contrast Heinrich-Events are the result of AMOC changes. Thus, in the context of potential ice shield melting and increasing precipitation in the northern North Atlantic, Heinrich-Events may display a model scenario improving our understanding of the upcoming response of AMOC on climate changes.