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

基本信息

批准号：
1829824
负责人：
Rana Fine
金额：
$ 29.84万
依托单位：
University of Miami
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=1829824&HistoricalAwards=false
关键词：
Collaborative Research Water mass variability

项目摘要

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.

最近确定的南半球超埃及（SHSG）是南部亚热带回旋的嵌套系统。它从塔斯曼海扫出，向西运输水，并喂养大西洋热盐循环的上肢。亚抗二极异的模式水（SAMW）和南极中间水（AAIW）显着参与SHSG海洋间连接。通过这种联系，SAMW/AAIW可以分布在三个海盆中。最近的分析表明，已有两个十年的SHSG旋转，以及海间塔斯曼和阿古尔哈斯泄漏的增加。该项目将研究SAMW/AAIW的随时间变化的性质及其与加强SHSG的海界之间的联系。 SAMW/AAIW是大量的水量，占用大量大气气体，这对生命和气候很重要 - 例如氧气和二氧化碳。它们是SHSG界面间连接的两个重要水质量。 SHSG的加强与大气模式相关，例如南环模式（SAM）。但是，预测臭氧层的回收将削弱SAM。因此，SHSG和Tasman和Agulhas是否继续加强是一个悬而未决的问题。同样未知的是这些循环中的可变性如何与SAMW/AAIW的变异性及其界面间连通性联系在一起。数据和模型将用于评估南部回旋的连通性及其与大气模式（Sam，El Nino Southern振荡（ENSO）和印度洋偶极子（IOD））的相关性。此外，从观测值中的估计值将作为模型输出的测试有用。这项研究将通过在观察数据和模型输出的分析中培训加州大学洛杉矶分校的博士后研究员的培训。它将通过建立不同学科（物理和化学海洋学）与不同机构（UCLA和迈阿密大学）之间的合作来增强研究和教育的基础设施。这项工作将是SAMW/AAIW的首次系统研究及其目前的变异性加强SHSG。 SAM的可变性以及十多年来的ARGO数据和最近的模型进步使得研究SAMW/AAIW及其与SHSG界面间连接的联系可能，并且可以及时。总体目标是：（1）估算三个南部亚热带海洋中每年平均的SAMW/AAIW特性和俯冲率，（2）评估多少SAMW/AAIW从一个南部的亚热带Gyre运输到另一个，并评估它们的路径和体积如何随时间变化并与SHSG旋转相关，（3）探索南部亚热带海洋中水质量变异性的原因，特别注意与浮力相关的可变性，SHSG旋转和大气模式。为了实现这些目标，将分析可用的卫星和Argo数据，结果将用于告知海洋一般循环模型的输出和模拟的被动/伴随示踪剂。该奖项反映了NSF的法定任务，并被认为值得通过评估值得支持。利用基金会的知识分子和更广泛的影响审查标准。