Circulation of the Ross Gyre

罗斯环流是南大洋两个主要环流之一，在维持全球翻转环流中起着重要作用。然而，由于其偏远的位置和不利的天气条件，该地区的采样和了解很少。目前对罗斯环流的认识非常有限，需要新的观测和分析来了解罗斯环流和南极绕极流之间的热、氧、营养物质和盐的输送。新的海洋数据将与美国、新西兰和澳大利亚的合作伙伴一起收集和分析，以确定与罗斯环流有关的大尺度通量的结构和特征。此外，从该项目中获得的知识将增强我们对受气候变化强烈影响的全球翻转环流的理解。一名研究生和一名博士后研究员将接受在恶劣的自然环境中工作的培训，他们将获得国际合作的经验。该项目将利用以大学为基础的REU（本科生研究经验）计划，向本科生介绍海洋学研究和数据分析技术。总的来说，拟议的工作解决了一个及时和重要的主题，这对于理解南大洋和全球的环流至关重要。罗斯环流中的大尺度环流、涡旋通量和平流在南极环极流和南极边缘之间产生净交换。本项目旨在通过分析大尺度动力学和性质输运，确定低位涡度环极深水（CDW）与该地区边缘的净源和净汇，将这些过程联系起来。主要目标是确定罗斯环流和相关子环流的结构和输送，量化ACC和罗斯环流之间的相互作用，包括地形在局部经向交换中的作用，并确定南极斜坡流和罗斯环流之间的联系。主要假设是，在环流的西部边界，向北流动的边界流靠近ACC，经过修正的环极深水沿着环流的西缘进入环流，被涡流强烈混合，消除了环流的许多特征。环流的东段经历了高度变化的风强迫和强烈的ACC不稳定性，增强了CDW在环流中的混合，并被带到大陆边缘。因此，三个过程：环流、涡流通量和上升流协同作用。利用水文和浮子剖面资料分析和南大洋状态估计（SOSE）模式分析，了解罗斯环流的大尺度环流、涡旋通量和平流。水文测量部分将包括两项主要活动，重点是基于船舶的水文测量和基于浮子的水文测量。建议在罗斯环流中专门部署15个剖面浮标，以提高环流的覆盖范围；这些浮存金将得到美国各项目以及澳大利亚和意大利同行的额外浮存金的补充。

The Ross Gyre, one of two main gyres in the Southern Ocean, serves an important role in maintaining the global overturning circulation. However, due to its remote location and unfavorable weather conditions, this area is poorly sampled and understood. The current knowledge of the Ross Gyre is very limited and new observations and analyses are needed to understanding the transport of heat, oxygen, nutrients and salt between the Ross Gyre and the Antarctic Circumpolar Current (ACC). New ocean data will be collected and analyzed in collaboration with partners in the US, New Zealand, and Australia to determine the structure and characteristics of large-scale fluxes associated with the Ross Gyre. In addition, the knowledge gained from the project will enhance our understanding of global overturning circulation, which is strongly influenced by climate change. A graduate student and a postdoctoral researcher will trained in working within a harsh natural environment and they will gain experience with international collaborations. The project will leverage a university-based REU (Research Experience for Undergraduates) program to introduce undergraduate students to oceanographic research and data analysis techniques. Overall, the proposed work addresses a timely and important topic that is critical to understanding circulation in the Southern Ocean and globally. The large-scale gyre circulation, eddy fluxes, and advection in the Ross Gyre act to produce net exchange between the Antarctic Circumpolar Current (ACC) and the Antarctic margin. This project aims to relate these processes by analyzing the large-scale dynamics, property transports, and determine the net sources and sinks of low potential vorticity Circumpolar Deep Water (CDW) to the margin in this region. The main objectives are to determine the structure and transport of the Ross Gyre and associated sub-gyres, to quantify the interactions between the ACC and Ross Gyre, including the role of topography in localizing meridional exchange and to determine the connection between the Antarctic Slope Current and the Ross Gyre The main hypothesis is that in the western limits of the gyre, where northward flowing boundary currents are in proximity of the ACC, modified Circumpolar Deep Water entering the gyre along its western rim is strongly mixed by eddies, removing much of its identifying characteristics. The eastern sector of the gyre experiences highly variable wind forcing and strong ACC instabilities, enhancing the mixing of CDW into the gyre where it is carried toward the continental margin. Thus three processes: gyre circulation, eddy fluxes, and upwelling act in concert. A program of hydrographic and float profile data analyses and an analysis of the Southern Ocean State Estimate (SOSE) model will be used to understand the large-scale gyre circulation, eddy fluxes and advection in the Ross Gyre. The hydrographic component will involve two primary activities, focused ship-based hydrography and float-based hydrography. A dedicated deployment of 15 profiling floats in the Ross Gyre is proposed to enhance coverage in the gyre; these floats will be complemented with additional float contributions from US programs and colleagues in Australia and Italy.