Circulation of the Ross Gyre

罗斯环流是南大洋的两个主要环流之一，在维持全球倾覆环流方面发挥着重要作用。然而，由于地理位置偏远，气候条件不利，该地区的样本和了解程度很低。目前对罗斯环流的了解非常有限，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量、氧气、营养物质和盐分的输送。将与美国、新西兰和澳大利亚的合作伙伴合作收集和分析新的海洋数据，以确定与罗斯环流相关的大范围通量的结构和特征。此外，从该项目中获得的知识将增强我们对全球翻转环流的理解，全球翻转环流受到气候变化的强烈影响。一名研究生和一名博士后研究员将接受在恶劣自然环境中工作的培训，他们将获得国际合作的经验。该项目将利用大学为基础的REU(本科生研究经验)计划，向本科生介绍海洋研究和数据分析技术。总体而言，拟议的工作涉及一个及时而重要的专题，该专题对于了解南大洋和全球的环流至关重要。罗斯环流中的大尺度涡旋环流、涡通量和平流在南极绕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、性质输送将这些过程联系起来，并确定该地区边缘低位涡绕极深水(CDW)的净源和汇。主要目的是确定Ross Gyre和相关次环流的结构和输送，量化ACC和Ross Gyre之间的相互作用，包括地形在定位经向交换方面的作用，以及确定南极坡流和Ross Gyre之间的联系。主要假设是，在向北流动的边界流靠近ACC的环流西端，沿其西缘进入该环流的修正环极深水强烈地被涡旋混合，消除了它的许多特征。环流东段经历了高度多变的风强迫和强的ACC不稳定，增强了CDW进入环流的混合，在那里它被带到大陆边缘。因此，三个过程：涡旋环流、涡旋通量和上升流共同作用。将使用水文和浮标剖面数据分析程序以及南大洋状态估计(SOSE)模式的分析来了解罗斯环流中的大尺度涡旋环流、涡旋通量和平流。水文学部分将涉及两项主要活动，重点是船舶水文学测量和浮标水文学测量。建议在罗斯环流中专门部署15个剖面花车，以加强环流的覆盖范围；这些花车将得到美国项目以及澳大利亚和意大利同事的额外贡献。

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.