Inverse Modeling of the Glacial Ocean

冰川海洋的反演模拟

• 批准号: 0524927
• 负责人: Olivier Marchal
• 金额: $ 35.8万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0524927&HistoricalAwards=false
• 关键词: Inverse; Modeling; Glacial; Ocean

Under this award the PIs will use an inverse modeling approach first pioneered by LeGrand and Wunsch (1995), to try to solve the origin of nutrient-rich waters below a depth of about 2.5 km in the Atlantic during the Last Glacial Maximum (around 21,000 years before present). This feature has been known for about two decades from measurements of d13C and Cd/Ca on fossil shells of benthic foraminifera. The inverse model will be used to test the validity of three possible mechanisms: a change in the deep circulation, a change in the nutrient concentration of the water mass end-members, and a change in the rates of organic matter remineralization at depth. Several critical extensions of the LeGrand and Wunsch will be undertaken: (i) the non-conservative character of the nutrients will be considered; (ii) benthic Cd/Ca and Zn/Ca data, in addition to benthic a 13C and a18O, will be incorporated; (iii) new benthic a13C data from the western Atlantic basin, which is a main flow path of deep waters, will be used; and (iv) the model domain will be extended to include the South Atlantic, where the nutrient proxy database has been largely improved since LW95.The project will include four major tasks: (I) a critical assessment of the existing nutrient proxy data, culminating with an estimate of the uncertainty of each datum; (II) the development of an inverse model of the circulation in the deep Atlantic; (III) the combination of the model with modern observations to test the model and to provide a reference state for hypothesis testing; and (IV) the combination of the model with data to test various hypotheses of nutrient enrichment in the glacial abyssal Atlantic. The project will involve a graduate student and a post-doc investigator and will contribute to fill the gap that exists today between the community of paleoceanographers and the community of physical oceanographers. It will bring together a modeler, a paleoceanographer and a physical oceanographer.

根据这一奖项，PIS将使用由LeGrand和Wunsch(1995)首创的反向建模方法，试图解决最后一次冰川盛期(大约比现在早21,000年)期间大西洋深度约2.5公里以下营养丰富的水域的起源问题。通过对底栖有孔虫化石壳的d13C和Cd/Ca的测量，这一特征已被发现约20年。反模型将被用来检验三种可能机制的有效性：深层循环的变化，水团末端成员营养浓度的变化，以及深层有机质再矿化速率的变化。将对LeGrand和Wunsch进行几个关键的扩展：(1)将考虑营养物质的非保守性；(2)除了海底a~(13)C和a~(18)O外，还将纳入海底Cd/Ca和Zn/Ca数据；(3)将使用来自大西洋西部盆地的新的海底a~(13)C数据，这是深水的主要流动路径；该项目将包括四项主要任务：(1)对现有营养物质替代数据进行关键评估，最终估计每一数据的不确定性；(2)开发一个大西洋深层环流的逆模型；(3)将该模型与现代观测相结合，以检验该模型并为假设检验提供一个参考状态；(4)将该模型与数据相结合，以检验关于大西洋冰川深海营养物质丰富的各种假说。该项目将涉及一名研究生和一名博士后调查员，并将有助于填补目前古海洋学家社区和物理海洋学家社区之间存在的空白。它将汇集一名模型师、一名古海洋学家和一名物理海洋学家。