Long-term ventilation changes of Subpolar Mode Waters in the North Atlantic Ocean and its impact on the oxygen distribution

北大西洋副极地模态水域的长期通风变化及其对氧分布的影响

• 批准号: 440908407
• 负责人: Dr. Ilaria Stendardo
• 金额: --
• 依托单位: Abteilung Ozeanographie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/440908407?language=en
• 关键词: Long; term; ventilation; changes; Subpolar

Ocean ventilation is a process that transfers properties, such as oxygen and carbon dioxide from the surface into the ocean interior where they are propagating following mainly the circulation pathways. In a warming ocean as a result of climate change, density stratification increases leading to reduced ventilation and loss of oxygen, particularly in the subpolar region. In the subpolar North Atlantic Ocean, Subpolar Mode Waters (SPMWs) are formed during late winter convection following the cyclonic circulation of the subpolar gyre. They participate in the upper flow of the Atlantic overturning circulation (AMOC) and provide much of the water that is eventually transformed into several components of the North Atlantic Deep Water (NADW), the cold, deep part of the AMOC. Thus, understanding how these water masses are affected by ventilation changes will help us to better understand the variability in the AMOC. The objectives of this proposal are: 1) investigate the effect of ventilation changes on the formation of SPMWs and on the volume occupied by these water masses over the last five decades, 2) investigate the long-term variability of SPMW properties with a particular focus on the oxygen variability, 3) evaluate the relationship within the SPMW with respect to changing ventilation ages and oxygen utilization rate (OUR) to better distinguish between the three main mechanisms driving the oxygen changes in the ocean: air-sea gas exchanges, circulation and marine biology and utilize the output of a high resolution model to analyse the mechanisms driving the observed changes.

海洋通风是一个将诸如氧气和二氧化碳等物质从海洋表面转移到海洋内部的过程，在那里它们主要通过循环途径传播。在气候变化导致的海洋变暖中，密度分层增加导致通风减少和氧气损失，特别是在亚极地地区。在北大西洋亚极区，亚极模态水（SPMWs）是在亚极环流气旋环流后的冬末对流过程中形成的。它们参与了大西洋翻转环流（AMOC）的上层流动，并提供了大量的水，这些水最终转化为北大西洋深水（NADW）的几个组成部分，这是大西洋翻转环流中寒冷的深层部分。因此，了解这些水团如何受到通风变化的影响将有助于我们更好地理解AMOC的变异性。本建议的目标是：1)研究近50年来通气变化对SPMW形成和这些水团所占体积的影响；2)研究SPMW性质的长期变异性，特别是氧气变异性；3)评估SPMW内部与通气年龄和氧气利用率（OUR）变化的关系，以更好地区分驱动海洋氧气变化的三种主要机制。海气交换，循环和海洋生物学，并利用高分辨率模型的输出来分析驱动观察到的变化的机制。