Collaborative Research: Water mass variability and connectivity in a strengthening Southern Hemisphere Super-Gyre

合作研究：南半球超级环流增强中的水量变化和连通性

• 批准号: 1829809
• 负责人: Tangdong Qu
• 金额: $ 59.79万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-10-01 至 2022-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1829809&HistoricalAwards=false
• 关键词: Collaborative; Research; Water; mass; variability

The recently identified Southern Hemisphere Super-Gyre (SHSG) is a nested system of the southern subtropical gyres. It sweeps out of the Tasman Sea, transports waters westward, and feeds the upper limb of the Atlantic thermohaline circulation. The Sub-Antarctic Mode Water(SAMW) and Antarctic Intermediate Water (AAIW) are prominently involved in the SHSG inter-ocean connection. Through this connection, the SAMW/AAIW can be distributed among the three ocean basins. Recent analysis has revealed a two-decade-long SHSG spin-up, and an increase in the inter-ocean Tasman and Agulhas Leakages. The project will study the time-varying nature of SAMW/AAIW and their inter-ocean link to a strengthening SHSG. The SAMW/AAIW are large volume water masses that take up substantial quantities of atmospheric gases, which are important for life and climate - such as oxygen and CO2. They are two significant water masses that are involved in the inter-ocean connection of the SHSG. Strengthening of SHSG has been correlated to atmospheric modes, e.g., Southern Annular Mode (SAM). However, recovery of the ozone layer is predicted to weaken the SAM. Thus, whether the SHSG and the Tasman and Agulhas Leakages continue strengthening or not is an open question. Also unknown is how variability in these circulations link to variability in SAMW/AAIW and their inter-ocean connectivity. Data and models will be used to assess connectivity of the southern gyres and their correlations with atmospheric modes (SAM, El Nino Southern Oscillation (ENSO), and Indian Ocean Dipole (IOD)). In addition, estimates from the observations will be useful as tests for model outputs. The research will promote education by the training of a postdoctoral fellow at UCLA in the analysis of observational data and model outputs. It will enhance infrastructure for research and education by establishing collaborations between different disciplines (physical and chemical oceanography) and different institutions (UCLA and University of Miami).This work would be the first systematic study of the SAMW/AAIW and their variability in a presently strengthening SHSG. Variability in the SAM, together with over a decade of Argo data and recent model advances make study of the SAMW/AAIW and their link to the SHSG inter-ocean connection possible and timely. The overall objectives are: (1) To estimate the annually averaged SAMW/AAIW properties and subduction rates in the three southern subtropical oceans, (2) To evaluate how much of the SAMW/AAIW is transported from one southern subtropical gyre into another, and how their pathways and volume transports vary with time and correlate with the SHSG spin-up, and (3)To explore the causes of water mass variability in the southern subtropical oceans with particular attention to variability associated with buoyancy fluxes, the SHSG spin-up and atmospheric modes. To achieve these objectives, available satellite and Argo data will be analyzed, and the results will be used to inform output from ocean general circulation models and simulated passive/adjoint tracers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

最近发现的南半球超级环流（SHSG）是南亚热带环流的嵌套系统。它扫出塔斯曼海，向西输送海水，并为大西洋温盐环流的上肢提供水源。亚南极模式水（SAMW）和南极中层水（AAIW）主要参与SHSG的海洋间连接。通过这种连接，SAMW/AAIW可以分布在三个洋盆之间。最近的分析显示，SHSG 持续旋转了长达两个十年的时间，并且大洋间的塔斯曼和厄加勒斯泄漏有所增加。该项目将研究 SAMW/AAIW 的时变性质及其与加强 SHSG 的跨洋联系。 SAMW/AAIW 是大量水团，吸收大量大气气体，例如氧气和二氧化碳，这些气体对生命和气候很重要。它们是参与 SHSG 海洋间连接的两个重要水体。 SHSG 的加强与大气模态有关，例如南环模（SAM）。然而，臭氧层的恢复预计会削弱 SAM。因此，SHSG以及塔斯曼和厄加勒斯泄漏事件是否继续加强仍是一个悬而未决的问题。同样未知的是这些环流的变化如何与 SAMW/AAIW 及其海洋间连通性的变化联系起来。数据和模型将用于评估南部环流的连通性及其与大气模式（SAM、厄尔尼诺南方涛动（ENSO）和印度洋偶极子（IOD））的相关性。此外，观测估计值可用作模型输出的检验。该研究将通过培训加州大学洛杉矶分校的博士后研究员进行观测数据和模型输出的分析来促进教育。它将通过在不同学科（物理和化学海洋学）和不同机构（加州大学洛杉矶分校和迈阿密大学）之间建立合作来加强研究和教育基础设施。这项工作将是对 SAMW/AAIW 及其在目前加强的 SHSG 中的可变性的首次系统研究。 SAM 的可变性，加上十多年来的 Argo 数据和最近的模型进展，使得对 SAMW/AAIW 及其与 SHSG 海洋间连接的联系的研究成为可能且及时。总体目标是：（1）估计三个南亚热带海洋的年平均 SAMW/AAIW 特性和俯冲率，（2）评估有多少 SAMW/AAIW 从一个南亚热带环流输送到另一个南亚热带环流，以及它们的路径和体积输送如何随时间变化以及与 SHSG 自转的相关性，以及（3）探索南部亚热带水量变化的原因 亚热带海洋，特别关注与浮力通量、SHSG 自旋和大气模式相关的变化。为了实现这些目标，将对可用的卫星和 Argo 数据进行分析，结果将用于为海洋环流模型和模拟被动/伴随示踪剂的输出提供信息。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

An Anti‐Phase Relationship Between the Subtropical Underwater and Eastern Subtropical Mode Water in the South Pacific During 2004–2020

• DOI: 10.1029/2021gl096601
• 发表时间: 2022-01
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Yingying Wang-;Tangdong Qu-;Yiyong Luo-;Rana A. Fine-

Spin‐Up of the Southern Hemisphere Super Gyre

• DOI: 10.1029/2018jc014391
• 发表时间: 2019-01
• 期刊: Journal of Geophysical Research: Oceans
• 作者: T. Qu;I. Fukumori;R. Fine