Timing and impact of variable Arctic outflow on the Atlantic Meridional Overturning Circulation

北极流出量变化对大西洋经向翻转环流的时间和影响

基本信息

批准号：
NE/X011690/1
负责人：
Pierre Josso
金额：
$ 8.86万
依托单位：
British Geological Survey
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FX011690%2F1
关键词：
Timing impact variable Arctic outflow

项目摘要

The North Atlantic Deep Water (NADW) constitutes the major deep oceanic current of the Atlantic Overturning Meridional Circulation (AMOC), distributing heat throughout the globe and affecting nutrients distribution sustaining marine ecosystems and human fishing grounds, whilst variations in its intensity have been linked to changes in productivity, current strength, regional and global climate throughout the Cenozoic. The NADW is a mixture of deep currents originating from the Labrador Sea and the Arctic Ocean. Contribution from the latter component to NADW is largely influenced by the depth of the two gateways connecting the Nordic Sea to the North Atlantic basins on either side of Iceland. These gateways are shallower than 1500 m and the volume of Arctic overflow will vary directly in response to changes in the relative depth of the passages. Lower sea level during glaciations and periodic increased mantle activity under Iceland, effectively raising land and seafloor, will directly constrain the influx of cold and dense Arctic Water, weakening the NADW and overall AMOC on geological time scales.This project will exploit the capacity of ferromanganese crusts to record the signature of oceanic currents in their stratigraphy to track past changes in the strength, source, and provenance of the NADW components. Using samples from two key localities in the North Atlantic, high-resolution isotope records will be produced to investigate how the NADW varied over the last 20-30 Ma in response to glaciations and mantle pulses. These records will be dated using a new method for time calibration based on astronomical parameters and their influence on the chemical signature of these samples. The information gained will be used to inform future climate models predicting the response of this major oceanic current to disturbances.

北大西洋深水（NADW）构成了大西洋推翻子弹循环（AMOC）的主要深海电流，在全球范围内散发热量，并影响持续的养分分布海洋生态系统和人类捕鱼场，而其强度的变化与生产力的变化相关，当前的强度和全球强度与全球强度相关，遍布整体，遍布整体。 NADW是源自拉布拉多海和北极海洋的深水的混合物。从后者到NADW的贡献在很大程度上受到将北欧海与冰岛任一侧北大西洋盆地相连的两个门户的深度的影响。这些网关大于1500 m，并且北极溢流的体积会随着通道相对深度的变化而直接变化。冰岛下的海拔较低的海平面和周期性增加的地幔活动有效地增加了土地和海底，将直接限制寒冷和茂密的北极水的涌入，削弱NADW和对地质时间尺度的整体AMOC。该项目将利用这些项目的能力，以记录其在阶层中的构成构成的构图，以追踪其阶层的构成，这些层次是构成了海洋的范围，这些阶层的构成源于海洋的范围，这些阶层的范围是众所周知的，构成了海洋的范围，构成了海洋的范围。成分。使用来自北大西洋两个关键地区的样品，将生成高分辨率同位素记录，以研究NADW在对冰川和地幔脉冲的响应中如何在最后20-30 mA中变化。这些记录将使用一种基于天文学参数及其对这些样品化学特征的影响的新方法进行日期进行时间校准。获得的信息将用于告知未来的气候模型，以预测这一主要海洋电流对干扰的反应。