Subantarctic Mode Water and Antarctic Intermediate Water mass formation and distribution: an observational-model synthesis using a Southern Ocean state estimate

亚南极模式水和南极中层水团的形成和分布：使用南大洋状态估计的观测模型综合

• 批准号: 0850869
• 负责人: Ivana Cerovecki
• 金额: $ 37.5万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 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: 2009-06-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0850869&HistoricalAwards=false
• 关键词: Subantarctic; Mode; Water; Antarctic; Intermediate

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Antarctic Intermediate Water (AAIW) is the densest of circumpolar Subantarctic Mode Waters (SAMW). AAIW fills the southern hemisphere and world tropical oceans at depths of 800 m to 1000 m. These waters are important in the global freshwater budget and may impact long-term climate variability through their influence on North Atlantic Deep Water (NADW) formation. Decadal freshening of Pacific AAIW may be associated with anthropogenic climate change. AAIW affects the stratification of the tropical ocean, and variability in AAIW may thus influence variations in the El Niño/Southern Oscillation. INTELLECTUAL MERIT. The central goal of this project is to characterize and quantify the formation of Subantarctic Mode Water and Antarctic Intermediate Water in an eddy resolving Southern Ocean State Estimate (SOSE), to describe their pathways in the SOSE ocean interior at eddy to global lateral scales, to compare the results with the observations, and to identify key processes and locations for SAMW and AAIW formation in support of organizing future fieldwork. The work will also include assessing the fidelity of estimated atmospheric forcing fields, especially at smaller (meso) scales. The investigators will synthesize the results of previous and ongoing projects, focusing on Southern Ocean mode and intermediate water observations and model results. Two years (2005 and 2006) of an eddy permitting (1/6° horizontal resolution) Southern Ocean State Estimate (SOSE) that assimilates observations, including those from two recently cruises in the southeastern Pacific mode water formation region, are available. SOSE permits comparison of the observational (cruise-based) picture of Southern Ocean water mass formation and spreading in the ocean interior with that in a numerical (assimilating) ocean of unprecedented lateral resolution and realism of air-sea forcing. SOSE assimilates surface fluxes, but adjusts them to be dynamically consistent with the oceanic fields, all with horizontal resolution of 1/6°. The investigators have completed a detailed comparison of large scale pattern of SOSE air-sea fluxes with those in the literature, finding them to be a notable improvement over previous flux products, and has also begun a study of water masses in SOSE, which shows that the SOSE fluxes more faithfully capture the density ranges within which SAMW/AAIW is formed than do the standard NWP flux products. A related study of mean flow and eddy dynamics in a different numerical model of Southern Ocean circulation will provides the opportunity to compare water mass properties and distributions in SOSE with those in a stand-alone ocean model of comparable resolution. The co-PI, Professor Talley will provide leadership in synthesizing SAMW and AAIW observations and model results. As a new post-doc at Scripps Institution of Oceanography funded through another project, Dr. Mazloff will continue the SOSE assimilation, extending it in time and data coverage.BROADER IMPACTS: This analysis will document in detail the hydrographic properties of the SOSE numerical representations of Southern Ocean circulation and of their corresponding ocean surface forcing fields in comparison with existing observations and literature. The results will be a foundation upon which to (i) plan and evaluate new observational studies, and to (ii) plan and evaluate new ocean and or ocean-atmosphere model studies, particularly studies intended to evaluate the effects of processes and/or changes in the Southern Ocean on climate. All SOSE fields are publicly available.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。南极中层水（AAIW）是环极亚南极模式沃茨（SAMW）的定义。AAIW填充南半球和世界热带海洋800米至1000米深处。这些沃茨在全球淡水收支中很重要，并可能通过影响北大西洋深水的形成而影响长期的气候变化。太平洋AAIW的年代际淡化可能与人为气候变化有关。AAIW影响热带海洋的分层，因此AAIW的变化可能会影响厄尔尼诺/南方涛动的变化。智力优势。该项目的中心目标是表征和量化的形成亚南极洲模态水和南极中层水在涡分辨南大洋状态估计（SOSE），描述其路径在SOSE海洋内部在涡全球横向尺度，比较结果与观察，并确定关键的过程和位置SAMW和AAIW的形成，以支持组织未来的实地考察。这项工作还将包括评估估计的大气强迫场的保真度，特别是在较小的（中）尺度上。调查人员将综合以前和正在进行的项目的结果，重点是南大洋模式和中层水观测和模式结果。两年（2005年和2006年）的涡流允许（1/6°水平分辨率）南大洋状态估计（SOSE），该估计吸收了观测结果，包括最近在东南太平洋模式水形成区进行的两次巡航的观测结果。SOSE允许比较南大洋水团形成和在海洋内部扩散的观测（基于巡航）图片与前所未有的横向分辨率和现实主义的海气作用力的数值（同化）海洋。SOSE同化地表通量，但调整它们以使其与海洋场动态一致，所有这些都具有1/6°的水平分辨率。研究人员已经完成了SOSE海气通量的大尺度模式与文献中的详细比较，发现它们比以前的通量产品有显着的改进，并且还开始研究SOSE中的水团，这表明SOSE通量比标准NWP通量产品更忠实地捕获SAMW/AAIW形成的密度范围。在一个不同的数值模式的南大洋环流的平均流量和涡动动力学的相关研究将提供机会，比较SOSE与那些在一个独立的海洋模式的可比分辨率的水团特性和分布。共同PI，塔利教授将提供综合SAMW和AAIW观测和模型结果的领导。Mazloff博士将继续SOSE同化，在时间和数据coverage.BROADER IMPLEMENTARY：这项分析将详细记录南大洋环流的SOSE数值表示及其相应的海洋表面强迫场与现有观测和文献相比的水文特性。研究结果将作为基础，以便㈠规划和评价新的观测研究，㈡规划和评价新的海洋和/或海洋-大气模型研究，特别是旨在评价南大洋的过程和/或变化对气候的影响的研究。所有SOSE字段都是公开可用的。