Eddy/tidal Water Mass Transformation and Transport in the Weddell Sea

威德尔海支持一系列对南极和全球范围的海洋环流和气候至关重要的过程。温暖的深水(WDW)，发现在近海的中等深度，入侵到大陆架，有可能推动费尔奇纳-罗恩冰架的快速后退。WDW的一种改进形式与沿海冰川产生的高盐度陆架水混合，并与海洋末端冰川底部融化产生的冰架水混合，产生南极底层水(AABW)。AABW的净出口为大约50%的地下海洋提供了通风，全球储存的碳大约是大气的30倍。因此，过去几十年观测到的AABW显著变暖和变新可能表明南极环流的重新安排，对深海氧气浓度、大气二氧化碳浓度和海平面上升的长期变化产生了影响，这些变化尚未量化。本项目使用高性能数值模拟(高分辨率MIT全球环流模式)来评估潮汐和涡旋在导致ABW产生的一系列水团转化中的相对作用。湍流特征，如中尺度和亚中尺度特征(有时称为海洋天气)都很小，使得它们在模型中的空间和时间表示需要大量的计算。正在提出的关键问题是，中尺度涡旋在将环极地温暖的深水向上输送到大陆架上并在那里放弃热量的过程中所起的作用，以及将AABW输出到中央深层韦德尔环流的过程中所起的作用。众所周知，中尺度、次中尺度和潮汐涡旋对于理解AABW水团转化和更广泛的南大洋环流是至关重要的。南极海洋环流特征的变化或重新安排反过来可能对海洋吸收多余的二氧化碳和热量、南极冰架的稳定性和海平面上升产生影响。该项目将提供一个博士后研究职位，并帮助开始职业生涯早期的教职员工的职业生涯。将向更广泛的科学界提供区域模型速度场和属性场，以规划观测活动，并促进未来的合作，以调查南极大陆边缘周围的生物地球化学示踪剂输送和大气-海洋交换。

The Weddell Sea supports a range of processes that are critical to the Antarctic and global-scale ocean circulation and to climate. Warm Deep Water (WDW), found offshore at mid-depth, makes incursions up onto the continental shelf that have the potential to drive rapid retreat of the Filchner-Ronne ice shelf. A modified form of WDW mixes with High Salinity Shelf Water produced in coastal polynyas, and with Ice Shelf water produced by basal melting of marine-terminating glaciers produces Antarctic Bottom Water (AABW). The net export of AABW ventilates around 50% of the subsurface ocean, and globally stores around 30 times as much carbon as the atmosphere. Thus the significant observed warming and freshening of AABW over the past few decades may indicate a rearrangement of the Antarctic circulation, with implications for long-term changes in deep-ocean oxygen concentration, atmospheric carbon dioxide concentration, and rises in sea level that are yet to be quantified. This project is using high performance numerical simulation (high-res MIT Global Circulation Model) to evaluate the relative roles of tides and eddies in the series of water mass transformation that leads to ABW production. Turbulent features such as mesoscale and sub-mesoscale features (sometimes called ?ocean weather?) are small, making their spatial and temporal representation in models computationally intensive. Key questions being asked are the role of mesoscale eddies in transporting circumpolar Warm Deep Water up onto the continental shelves where they give up their heat, and in export of AABW into the deep central Weddell Gyre. Mesoscale, submesoscale and tidal eddies are known to be critical to understanding AABW water mass transformation, and to the broader Southern Ocean circulation.Changes or rearrangements in Antarctic oceanic circulation features in turn may have implications for the uptake of excess CO2 and heat into the oceans, stability of the Antarctic ice shelves, and sea level-rise. The project will provide a post-doctoral research position and help commence the career of an early career faculty member. Regional model velocity and property fields will be made available to the wider scientific community for the purpose of planning observational campaigns, and in order to foster future collaborations to investigate biogeochemical tracer transport and atmosphere-ocean exchange around the Antarctic continental margins