A Numerical Study of the Patagonia Upwelling Region

巴塔哥尼亚上升流区域的数值研究

• 批准号: 0928348
• 负责人: Ricardo Matano
• 金额: $ 58.77万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0928348&HistoricalAwards=false
• 关键词: Numerical; Study; Patagonia; Upwelling; Region

The Patagonia shelf is a broad submarine terrace that extends from the mouth of the La Plata River (~36S) to the tip of Tierra del Fuego (~55S). Satellite and in-situ observations indicate that this region is an active upwelling center harboring some of the largest chlorophyll blooms of the world ocean, the most distinctive of which is located at the shelfbreak. Patagonia's shelfbreak upwelling brings iron and other nutrient from the deep layers of the Southern Ocean to the photic zone, fertilizing not only the shelf waters, but also the entire subpolar portion of the South Atlantic. Satellite observations, for example, show chlorophyll plumes extending from South America to Australia. Yet, in spite of its regional and hemispheric impact, we know little about Patagonia's upwelling regime or its interaction with the deep-ocean circulation, which this project intends to address. This is a modeling study to investigate the dynamical mechanisms driving Patagonia's shelfbreak upwelling and the interactions between the shelf and the deep ocean. The basic premise is that the shelfbreak upwelling is primarily modulated by the along-shelf variations of the bottom topography and time variations of the Malvinas Current transport. The study seeks to quantify the spatial and temporal variability of the upwelling and link it to the atmospheric forcing. It is hypothesized that, although local wind might have little impact over the upwelling, large-scale wind variations, particularly those over the Pacific and Indian basins might significantly influence its variability. The study will also identify the regions of Patagonia with the largest cross-shelf exchanges and identify the dynamical mechanisms controlling these exchanges. It is anticipated that Patagonia entrains Subantarctic waters through the Le Maire Straits and the shelfbreak region between ~50S and 46S, and primarily detrains at the Subtropical Shelf Front.Broader ImpactsThis study will contribute to the development to ongoing and future biological and geochemical projects of the southwestern Atlantic region. For example, the upwelling index that will be developed by this project will help to relate observed changes in the Patagonia's ecosystems to variations in the magnitude of the shelfbreak upwelling and to large-scale modes of climate variability. The identification of cross-shelf exchanges mechanisms (and regions) will contribute to our understanding of carbon cycles and the development of future observational programs. The multi-disciplinary workshop proposed as part of this project will foster international cooperation. The project includes support for a PhD student who, throughout her/his studies, will work in close collaboration with oceanographers in Latin America. This strategy should help to foster the north-south integration of the next generation of scientists interested in shelf dynamics.Intellectual MeritAt its most basic level this project proposes to test new ideas about the dynamical mechanisms generating shelfbreak upwelling and controlling cross-shelf exchanges in regions bounded by cyclonic western boundary currents. The arguments are general enough to be applicable to other similar regions (e.g., New Zealand, Japan, the Weddell Sea, etc), thus broadening the potential impact of the intellectual work developed in this project.

巴塔哥尼亚大陆架是一个广阔的海底阶地，从拉普拉塔河口（~ 36 S）延伸到火地岛的顶端（~ 55 S）。卫星和现场观测表明，这一区域是一个活跃的上升流中心，拥有世界海洋中一些最大的叶绿素水华，其中最具特色的是位于陆架区。巴塔哥尼亚的陆架断裂上升流将铁和其他营养物质从南大洋的深层带到了透光区，不仅覆盖了陆架沃茨，而且覆盖了南大西洋的整个副极地部分。例如，卫星观测显示叶绿素羽流从南美洲延伸到澳大利亚。然而，尽管它的区域和半球的影响，我们知道巴塔哥尼亚的上升流制度或其与深海环流的相互作用，这是本项目打算解决的。这是一个模拟研究，探讨动力机制驱动巴塔哥尼亚的陆架断裂涌升和陆架和深海之间的相互作用。基本的前提是，shelfbreak上升流主要是调制的沿大陆架变化的底部地形和时间变化的马尔维纳斯电流传输。该研究旨在量化上升流的空间和时间变化，并将其与大气强迫联系起来。据推测，虽然当地的风可能有上升流的影响不大，大规模的风的变化，特别是那些在太平洋和印度盆地可能会显着影响其变化。这项研究还将确定巴塔哥尼亚地区最大的跨大陆架交流，并确定控制这些交流的动力机制。据预计，巴塔哥尼亚夹带亚班纳沃茨通过勒梅尔海峡和shelfbreak区域之间的~ 50 S和46 S，主要在亚热带大陆架Front.Broader ImpactsThis研究将有助于发展正在进行的和未来的生物和地球化学项目的西南大西洋地区。例如，本项目将制定的上升流指数将有助于将巴塔哥尼亚生态系统中观察到的变化与陆架断裂上升流的幅度变化和大规模气候变异模式联系起来。跨大陆架交换机制（和区域）的识别将有助于我们对碳循环的理解和未来观测计划的发展。作为这一项目的一部分而提议的多学科讲习班将促进国际合作。该项目包括支持一名博士生，在她/他的研究中，将与拉丁美洲的海洋学家密切合作。这一战略应有助于促进对大陆架动态感兴趣的下一代科学家的南北一体化。智力价值在最基本的层面上，这一项目提议测试关于在以气旋西部边界流为界的区域产生大陆架断裂涌升和控制跨大陆架交换的动力机制的新想法。这些论点足够普遍，可以适用于其他类似地区（例如，新西兰，日本，威德尔海等），从而扩大了该项目中开发的智力工作的潜在影响。