Dynamics of Shelfbreak Processes and Shelf/Slope Exchange South of New England

最近的研究确定了西北大西洋大陆架水域的显着变暖趋势，以及2012年上半年等极端变暖事件。这些对大陆架生态系统和商业渔业都产生了重大影响。目前尚不清楚陆架水质量性质和环流的变化如何影响陆架断裂过程和陆架/坡度交换，以及交换过程如何反过来改变陆架水团。这个项目是一个更大的研究计划的初始阶段，最初设计的目的是探索多种交换机制，包括锋面蜿蜒、温暖核环的撞击和风力强迫。为了解决陆架/坡度交换的这些问题，将分析最近委托的海洋观测站倡议的先锋阵列的观测结果、其他历史和最近的水文测量结果以及遥感产品。研究人员还将进行面向过程的数值模拟，以研究主导交换过程的动力学机制，并量化它们的相对贡献。更大努力的最终目标是充分了解陆架/坡度交换过程及其对关键锋面和强迫参数的依赖。这个为期一年的项目将侧重于评估先锋阵列数据的质量和数量，并展示其在解决交换过程中的科学效用。这项研究的结果将通过与罗德岛商业渔业研究基金会的联合会议传达给商业捕鱼业成员。将与国家海洋渔业局的渔业科学家分享关于交换过程的动态、频率和年际变化的结果，以深入了解陆架/坡度交换过程可能如何在季节和年度间时间尺度上影响海洋生物资源。将在不同的公共场所发表演讲，讨论科学成果及其社会影响。假设i)搁置锋面曲折、墨西哥湾流暖核环的撞击和风的强迫都会引起显著的跨陆架交换，以及ii)这些交换过程受上游、近海和大气条件变化的影响，在广泛的时间范围内。。最近发展的关于搁置锋面有限振幅曲折的最不稳定波长和增长率的理论将通过观测得到验证。将对在温暖核环外围向近海移动的陆架水飘流的输送进行量化，并将其与最近根据实验室实验和有限观测得出的标度进行比较。先锋阵列数据连同大陆架上的其他水文数据，包括商业渔民收集的数据，将用于调查斜坡水或温暖核心环水的地下侵入频率和跨陆架渗透。将使用面向过程的区域模型进行动态分析和数据解释。

Recent studies have identified a significant warming trend in the shelf waters of the northwest Atlantic Ocean as well as extreme warming events such as during the first half of 2012. These have had major impacts on both the continental shelf ecosystem and commercial fisheries. It is unclear at this time how changing continental shelf water mass properties and circulation affect shelfbreak processes and shelf/slope exchange and how the exchange processes in turn modify shelf water masses. This project is the initial phase of a larger research plan originally devised to explore multiple exchange mechanisms involving the meandering of fronts, impingement of warm core rings and wind forcing. To address these issues of shelf/slope exchange, observations from the recently commissioned Ocean Observatories Initiative's Pioneer Array, other historical and recent hydrographic measurements, and remote sensing products will be analyzed. The investigators will also conduct process-oriented numerical modeling to investigate the dynamical mechanisms of dominant exchange processes and to quantify their relative contribution. The ultimate goal of the larger effort is to obtain sufficient understanding of shelf/slope exchange processes and their dependence on key frontal and forcing parameters. This one-year project will focus on assessing the quality and quantity of Pioneer Array data and demonstrating its scientific utility to resolve the exchange processes. The results from this study will be communicated to members of the commercial fishing industry through joint meetings with the Commercial Fisheries Research Foundation of Rhode Island. Results on the dynamics, frequency, and inter-annual variability of exchange processes will be shared with fisheries scientists of the National Marine Fisheries Service to gain insight into how shelf/slope exchange processes may be affecting living marine resources on seasonal and inter-annual time scales. Presentations will be made at various public venues to talk about the scientific results and their societal implications.It is hypothesized that i) shelfbreak frontal meanders, impingement of Gulf Stream warm-core rings, and wind forcing all induce significant cross-shelf exchange, and ii) these exchange processes are subject to the influences by the changing upstream, offshore, and atmospheric conditions over a broad range of time scales. . A recently developed theory for the most unstable wavelength and growth rate of finite amplitude meanders of a shelfbreak front will be validated against observations. Transports for streamers of shelf water that move offshore in the periphery of warm core rings will be quantified and compared to a recent scaling developed from laboratory experiments and limited observations. The Pioneer Array data along with other hydrographic data over the continental shelf, including data collected by commercial fishermen, will be used to investigate the frequency and cross-shelf penetration of subsurface intrusions of slope water or warm core ring water. A process-oriented regional model will be used for the dynamical analysis as well as data interpretation.