Collaborative Research: An Inverse Model Study of Abrupt Climate Change

根据该合同，pi将使用在最优控制理论和贝叶斯随机反演框架下开发的数据同化技术，将格陵兰岛古温度记录与大西洋海洋-大气系统的数值模型（一个相对简单的箱形模型和更复杂的Stocker/Wright纬向平均模型）结合起来。PIs希望估算在海洋同位素阶段3 （24.1-59.0 ka BP）期间大西洋MOC、Fh和地表淡水强迫的时间演变，这与格陵兰记录和模型中嵌入的物理一致。估计的进化，与来自大西洋沉积物的古海洋学记录相一致，将被用来评估该理论解释快速气候变化的充分性。古气候记录，特别是北大西洋地区的记录，记录了末次冰期的一系列暖期，通常被称为Dansgaard-Oeschger间冰期（DOI）。格陵兰冰中记录的doi的开始与几十年内发生的极大温度跳变（7-16℃）相对应。doi的发现表明，气候系统突然过渡到一个新的气候状态在动态上是可能的。理解doi的起源是评估未来“意外”转变可能性的重要组成部分。一个主要的突变理论认为大西洋经向翻转环流（MOC）以及纬向和深度积分热通量（Fh）对北半球冰盖冰川融水排放的敏感性。

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.