Collaborative Research: An Inverse Model Study of Abrupt Climate Change

根据这项合同，研究所将使用在最佳控制理论和贝叶斯随机反演框架内开发的数据同化技术，将格陵兰古温度记录和大西洋海洋-大气系统的数值模型（一个相对简单的箱模型和更复杂的Stocker/Wright分区平均模型）结合起来。PI希望在海洋同位素阶段3（24.1-59.0 ka BP）期间估计大西洋MOC，Fh和地表淡水强迫的时间演变，这些变化与格陵兰记录和模型中嵌入的物理学相一致。估计的演变，与来自大西洋沉积物的古海洋学记录相一致，将用于评估该理论是否足以解释快速的气候变化。 古气候记录，特别是来自北大西洋地区的记录，记录了末次冰期期间的一系列温暖阶段，通常被称为Dansgaard-Oeschger interstadials（DOI）。格陵兰冰中记录的DOI的开始对应于几十年内发生的极大的温度跳跃（7- 16 ℃）。DOI的发现表明，气候系统在动力学上有可能突然过渡到一个新的气候状态。了解DOI的起源是评估未来“意外”过渡可能性的重要组成部分。一个领先的突变理论调用的纬向翻转环流（MOC）和纬向和深度综合热通量（Fh）在大西洋的敏感性，从北方冰盖的冰川融水排放。

Under this award the PIs will use data assimilation techniques developed in the framework of optimal control theory and Bayesian stochastic inversion, to combine the Greenland paleotemperature record and numerical models of the ocean-atmosphere system in the Atlantic (a relatively simple box model and the more complex Stocker/Wright zonally-averaged model). The PIs hope to estimate the temporal evolutions of the Atlantic MOC, Fh, and surface freshwater forcing during the marine isotope stage 3 (24.1-59.0 ka BP) that are consistent with both the Greenland record and the physics embedded in the models. The estimated evolutions, in concert with paleoceanography records from Atlantic sediments, will be used to assess the adequacy of the theory to explain rapid climate change. Paleoclimate records, in particular those from the North Atlantic area, document a series of warm phases during the last glaciation, commonly referred to as Dansgaard-Oeschger interstadials (DOI). The onsets of DOIs recorded in Greenland ice corresponded to extremely large temperature jumps (7-16oC) that occurred within a span of a few decades. The discovery of DOIs demonstrates that it is dynamically possible for the climate system to make an abrupt transition to a new climate state. Understanding the origin of DOIs is an important part of assessing the possibility for future 'surprise' transitions. A leading theory of abrupt change invokes the susceptibility of the meridional overturning circulation (MOC) and zonally- and depth-integrated heat flux (Fh) in the Atlantic, to glacial meltwater discharges from northern hemisphere ice sheets.