Collaborative Research: Estuarine Response to Climate Forcing

将利用盐度观测、统计方法、现实的三维水动力模型和简化的二维数值模型，对河口盐度、层化和环流年际变化的原因进行调查。总体目标是量化河口环流、层化和盐度的年际变化，解释造成这种变化的物理机制，并评估这些指标在应对未来气候变化时可能发生的变化。观测分析和三维模拟将集中在切萨皮克湾和特拉华湾，这些海湾(A)有广泛的盐度数据库，(B)已经开发和验证了一个可靠的数值模式。将进行面向过程的模拟研究，以研究河口如何应对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。将进行多个模式后播，其中评估公海海平面、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，以调查盐分入侵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。对这些河口未来气候影响的预测将利用大西洋中部地区经过广泛评估的最先进气候模型的区域输出。对河口物理过程对气候变化和变化的敏感性的一般见解将通过(1)切萨皮克湾(部分混合)和特拉华湾(完全混合)的不同物理；(2)面向过程和现实的三维模拟研究；以及(3)在河流流量、潮汐速度幅度和河口几何的大参数空间上配置二维半分析模型。目前河口的大部分研究集中在相对较短的时间尺度(潮汐、与天气有关的和季节性的)。关于河口盐度、层化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需要一种严格的、以物理为基础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满足这一需求。这一研究项目将对更广泛的河口科学家和沿海管理者产生影响，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，以及对水质和牡蛎、螃蟹等生物资源的可持续性产生重大影响的因素。切萨皮克和特拉华湾管理社区将在为应对气候变化的影响做准备时获得长期模型模拟和分析产品。还将通过大西洋中部地区正在进行的几项气候评估活动，将结果传达给包括公众在内的广泛利益攸关方。因为这里开发的建模和数据分析方法可以应用于任何河口，而且因为我们将利用简化的二维模型来提供关于气候变化对大类河口的潜在影响的见解，所以这项工作的影响超出了切萨皮克和特拉华湾。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.