Late Quaternary Variability of the Agulhas Thermohaline Valve from Nd Isotopes in Planktonic Foraminifera

阿古拉斯流作为“大洋传送带”浅层暖水回流路线的组成部分，作为世界海洋中最大的西部边界流，计划在向大西洋输送热量和盐分方面发挥重要作用。印度洋水域向南大西洋的“泄漏”加剧了温跃层的盐碱化。这种预适应效应为北大西洋深水(NADW)的形成提供了正反馈，从而可能在驱动经向翻转环流中起到关键作用。这项研究调查了过去30,000年来“阿古拉斯渗漏”(AL)的变化，试图更好地限制通过渗漏进行的海水交换在过去的气候变化中作为大西洋主要环流变化的积极参与者所起的作用。浮游有孔虫的钕同位素组成将被用来重建Agulis泄漏强度和位置的变化。研究围绕4个假设展开：1)气候变暖时期AL较大(反之亦然)；2)在冰川消融期间，AL增加导致NADW出口增加；3)在末次冰期气候过渡期间，AL减少导致NADW出口减少；4)全新世和末次冰期，Agulhas背反射的位置相同。资金支持一名博士后研究人员和一种新的古海洋学代理人的应用。

As a component of the shallow warm water return route of the "great ocean conveyor", and as the largest western boundary current in the world ocean, the Agulhas Current plans an important role in the transfer of heat and salt into the Atlantic Ocean. This "leakage" of Indian Ocean waters into the South Atlantic contributes to increased salinification of the thermocline. This preconditioning effect provides a positive feedback for North Atlantic Deep Water (NADW) formation, and thereby may play a critical role in driving the Meridional Overturning Circulation. This research investigates changes in the "Agulhas Leakage" (AL) over the last 30,000 years, seeking to better constrain the role that the oceanic water exchange via leakage had in past climate changes as an active player in major circulatory changes in the Atlantic. The neodymium isotopic composition of planktonic foraminifera will be used to reconstruct changes in the Agulhas Leakage intensity and position. The research centers around four hypotheses: 1) the AL is greater during warmer climate periods (and vice versa), 2) increases in AL contributed to increases in NADW export during the deglaciation, 3) decreases in AL contributed to decreased NADW export during the climate transition of the last glacial period, and 4) the position of the Agulhas retroflection was the same during the Holocene and LGM. Funding supports a postdoctoral researcher and application of a new paleoceanographic proxy.