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

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。南极中间水（AAIW）是绕极亚南极模态水（SAMW）中密度最大的。AAIW遍布南半球和世界热带海洋，深度为800米至1000米。这些水域在全球淡水收支中很重要，并可能通过其对北大西洋深水（NADW）形成的影响而影响长期气候变率。太平洋AAIW的年代际更新可能与人为气候变化有关。AAIW影响热带海洋的分层，因此AAIW的变化可能影响El Niño/南方涛动的变化。知识价值。该项目的中心目标是表征和量化涡旋解析南大洋状态估计（SOSE）中亚南极模态水和南极中间水的形成，描述它们在涡旋到全球横向尺度的SOSE海洋内部的路径，将结果与观测结果进行比较，并确定SAMW和AAIW形成的关键过程和位置，以支持组织未来的实地工作。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）尺度上。调查人员将综合以前和正在进行的项目的结果，重点关注南大洋模式和中间水观测和模式结果。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）吸收了观测结果，包括最近两次在东南太平洋模态水形成区巡航的观测结果，是可用的。sse允许将观测到的（基于巡航的）南大洋水团在海洋内部形成和扩散的图像与具有前所未有的横向分辨率和海气强迫真实性的数值（同化）海洋的图像进行比较。sse同化地表通量，但将其调整为与海洋场动态一致，水平分辨率均为1/6°。研究人员已经完成了对SOSE海气通量的大尺度格局与文献的详细比较，发现它们比以前的通量产品有了显着的改进，并且还开始了对SOSE中水团的研究，结果表明SOSE通量比标准的NWP通量产品更忠实地捕捉了SAMW/AAIW形成的密度范围。在一个不同的南大洋环流数值模式中对平均流量和涡旋动力学的相关研究将提供机会，将SOSE中的水团性质和分布与具有可比分辨率的独立海洋模式中的水团性质和分布进行比较。Talley教授将领导综合SAMW和AAIW观测和模式结果。作为斯克里普斯海洋研究所的新博士后，马兹洛夫博士将继续sse同化工作，并在时间和数据覆盖范围上进行扩展。更广泛的影响：本分析将详细记录南大洋环流及其对应的海洋表面强迫场的sse数值表示的水文特性，并与现有观测和文献进行比较。这些结果将成为以下工作的基础：(1)计划和评估新的观测研究，(2)计划和评估新的海洋和/或海洋-大气模式研究，特别是旨在评估南大洋过程和/或变化对气候影响的研究。所有sse字段都是公开可用的。

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.