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The ventilation of South Georgia's Deep Waters

南乔治亚深水区的通风

基本信息

批准号：
1830856
负责人：
Ricardo Matano
金额：
$ 52.75万
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：
2018
资助国家：
美国
起止时间：
2018-10-01 至 2021-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1830856&HistoricalAwards=false
关键词：
ventilation South Georgia Deep Waters

项目摘要

This project aims to characterize the physical processes contributing to the entrainment of deep and benthic waters into the surface layers of the South Georgia Island (Southern Ocean) and to assess their sensitivity to climate variability. South Georgia (SG) hosts some of the largest chlorophyll blooms of the Southern Ocean. Observations suggest that the ocean circulation drives these blooms, but the nature of the physical processes underlying the fertilization process are unknown. A process-oriented modeling program will seek, on the one hand, to identify the sources and dynamical mechanisms underlying the fertilization of the SG region and, on the other hand, to evaluate their sensitivity to climate variability and climate change. The research is relevant to the climate and marine ecosystem community research.Understanding of SG's fertilization processes will not only contribute to the forecast of the impact of climate change on the regional ecosystems but also to anticipate the potential feedbacks that those ecosystems will have on the changing climate. Any change in the circulation in the SG, nutrient and iron input to the euphotic zone, continental margin discharge and biological activity will have a substantial effect on the balance of outgassing of natural CO2 and uptake of anthropogenic CO2. Furthermore, this study will provide some insight on which processes and on which scale the climate community model will have to resolve them. This research will also help in the design of field campaigns to address the unresolved questions of primary production in the Atlantic sector of the Southern Ocean and target sites where observations will provide answers to these questions. Graduate training will be an important component of the research.There are very few studies on the physical mechanisms sustaining SG's extraordinary blooms and, in particular, on its regional circulation. This is a matter of concern because observations suggest that South Georgia's blooms, which are an important component of the climate system, are primarily driven by physical processes. There are, for example, few studies on SG's shelf circulation and virtually none on its mass exchanges with the Southern Ocean. A pilot study, however, shows that shelf processes and its interaction with the deep ocean are critical to bio-geochemical balance of this region. The numerical experiments to be analyzed by this project are the state-of-the-art for this region. It is hypothesized that SG high productivity is based on vigorous water exchange between the shelf and the deep ocean and a persistent, albeit still under-appreciated, coastal upwelling system. Further, it is posited that SG fertilization is strongly dependent on wind forcing and the expected strengthening of the SO winds will also amplify the fertilization processes leading, therefore, to a negative feedback for climate change.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.

该项目的目的是描述促使深水和底栖生物水进入南乔治亚岛(南大洋)表层的物理过程，并评估它们对气候变化的敏感性。南乔治亚州(南乔治亚州)拥有南大洋中一些最大的叶绿素水华。观察表明，海洋环流驱动了这些水华，但肥化过程背后的物理过程的性质尚不清楚。一个面向过程的模拟程序一方面将寻求确定SG区肥力的来源和动力机制，另一方面将评估它们对气候变异性和气候变化的敏感性。这项研究与气候和海洋生态系统群落研究有关，了解SG的施肥过程不仅有助于预测气候变化对区域生态系统的影响，而且有助于预测这些生态系统对气候变化的潜在反馈。大气环流、输入到真光层的养分和铁、大陆边缘排放和生物活性的任何变化，都将对自然二氧化碳的放出和人为二氧化碳的吸收的平衡产生重大影响。此外，这项研究将提供一些关于气候社区模型必须解决这些问题的过程和规模的一些见解。这项研究还将有助于设计实地活动，以解决南大洋大西洋区段尚未解决的初级生产问题，以及观测将为这些问题提供答案的目标地点。研究生培训将是这项研究的一个重要组成部分。关于支持SG异常爆发的物理机制，特别是对其区域环流的研究很少。这是一个令人担忧的问题，因为观察表明，南乔治亚州的水华是气候系统的一个重要组成部分，主要是由物理过程驱动的。例如，关于SG的陆架环流的研究很少，几乎没有关于它与南大洋的大规模交换的研究。然而，一项初步研究表明，陆架过程及其与深海的相互作用对该地区的生物地球化学平衡至关重要。该项目将要分析的数值实验是该地区最先进的。假设SG的高生产力是建立在大陆架和深海之间强烈的水交换和持续的、尽管仍然被低估的沿海上升流系统的基础上的。此外，假设SG施肥强烈依赖于风强迫，预期的SO风增强也将放大施肥过程，从而导致对气候变化的负面反馈。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。