Collaborative Research: Estuarine Response to Climate Forcing

利用盐度观测、统计方法、现实三维水动力模型和简化二维数值模型，对河口盐度、分层和环流的年际变化原因进行研究。总体目标是量化河口环流、分层和盐度的年际变化，解释造成这种变化的物理机制，并对这些指标响应未来气候变化的可能变化进行评估。观测分析和三维建模将集中在切萨皮克和特拉华湾，其中(a)存在广泛的盐度数据库，(b)已经开发并验证了一个强大的数值模型。以过程为导向的模拟研究将进行，以检查河口如何响应河流径流和陆架盐度的年际变化、海平面上升以及潮汐和风混合的潜在变化。将进行多种模式的预测，评估公海海平面、河流流量、陆架盐度和气象强迫的年际变化的个别影响。统计模型将应用于历史盐度数据，研究盐侵入长度和河口分层如何随河流流量、陆架盐度和海平面上升而变化。对这些河口的未来气候影响的预估将通过使用已在中大西洋地区广泛评估过的最先进的气候模式的区域输出来进行。(1)切萨皮克湾（部分混合）和特拉华湾（完全混合）的不同物理特性将提供关于河口物理过程对气候变率和变化的敏感性的一般见解；(2)面向过程和现实的三维建模研究；(3)在河流流量、潮汐速度幅值和河口几何等大参数空间上配置二维半解析模型。知识价值。目前的河口研究大多集中在相对较短的时间尺度上（潮汐、天气相关和季节性）。人们对河口盐度、分层和环流的年际变化知之甚少。海平面上升和气候变化的必然性要求一种严格的、基于物理的方法来量化它们的影响。该项目通过在数值模拟、河口动力学、气候变化影响和时间序列分析方面具有互补专业知识的两个团队之间的合作努力来解决这一需求。更广泛的影响。该研究项目将影响更广泛的河口科学家和沿海管理人员，因为它将更好地量化气候变化对河口盐度和分层的潜在影响，这些因素极大地影响水质和牡蛎和螃蟹等生物资源的可持续性。长期模型模拟和分析产品将提供给切萨皮克和特拉华湾管理社区，因为他们准备应对气候变化的影响。结果还将通过中大西洋地区正在进行的几项气候评估活动，传达给广泛的利益攸关方，包括公众。由于这里开发的建模和数据分析方法可以应用于任何河口，并且因为我们将利用简化的二维模型来提供有关气候变化对广泛类型河口的潜在影响的见解，因此这项工作的影响超出了切萨皮克湾和特拉华湾。该提案的教育影响是通过支持河口动力学和气候变化学科界面的研究生和博士后研究。

An investigation into the causes of interannual variability in estuarine salinity, stratification and circulation will be conducted using salinity observations, statistical methods, realistic 3-Dimensional hydrodynamic models, and simplified 2-Dimensional numerical models. The overall objective is to quantify interannual variability of estuarine circulation, stratification, and salinity, to explain the physical mechanisms responsible for such variability, and provide an assessment of the likely changes in these metrics in response to future climate change. Observational analysis and 3-Dimensional modeling will be focused on Chesapeake and Delaware Bays, for which (a) extensive salinity databases exist, and (b) a robust numerical model has been developed and validated. Process-oriented modeling studies will be conducted to examine how the estuaries respond to interannual variability in river runoff and shelf salinity, sea-level rise and potential changes in tidal and wind mixing. Multiple model hindcasts will be conducted in which the individual impacts of interannual variability in open-ocean sea level, river flow, shelf salinity, and meteorological forcing are assessed. Statistical models will be applied to the historical salinity data to investigate how salt intrusion length and estuarine stratification vary with river flow, shelf salinity and sea level rise. Projections of future climate impacts on these estuaries will be made by using the regional output of state-of-the art climate models that have been extensively evaluated for the Mid-Atlantic region. General insights into the sensitivity of estuarine physical processes to climate variability and change will be afforded by (1) the differing physics of Chesapeake Bay (partially mixed) and Delaware Bay (well mixed); (2) process oriented and realistic 3-Dimensional modeling studies; and (3) configuration of 2-Dimensional semi-analytical models over a large parameter space of river flow, tidal velocity amplitude, and estuarine geometry.Intellectual Merit. Much of current estuarine research focuses on relatively short time scales (tidal, weather-related, and seasonal). Little is known of interannual variability in estuarine salinity, stratification, and circulation. The inevitability of sea-level rise and climate change demands a rigorous, physically based approach for quantifying their impacts. This project addresses that need with a collaborative effort between two teams with complementary expertise in numerical modeling, estuarine dynamics, climate change impacts, and time-series analysis.Broader Impacts. This research project will impact the broader community of estuarine scientists and coastal managers as it will better quantify the potential impacts of climate change on estuarine salinity and stratification, factors that greatly influence water quality and the sustainability of living resources such as oysters and crabs. The long-term model simulations and analysis products will be made available to the Chesapeake and Delaware Bay management communities as they prepare for the impacts of climate change. Results will also be communicated to a broad range of stakeholders, including the general public, through several climate assessment activities underway in the Mid-Atlantic Region. Because the modeling and data analysis approaches developed here can be applied to any estuary, and because we will utilize simplified 2-Dimensional model to provide insights about the potential impacts of climate change on a broad class of estuaries, the impacts of the work extend beyond Chesapeake and Delaware Bays. Educational impacts of the proposal are through the support of graduate and post-doctoral research at the interface of the disciplines of estuarine dynamics and climate change.