Physics Linking Shelf Circulation to Estuarine Inflow

控制沃茨从沿海流入河口或峡湾的源头的物理学将使用理论和理想化的数值实验来探索。 具体目标是对水源水的抽取深度和抽取的地理区域进行理论预测。这两个属性将被表示为控制环境变量的函数。参数空间将跨越各种各样的系统，从浅的沿海平原河口的缓坡架，深峡湾毗邻的货架交叉峡谷。这项研究将告知数值模拟人员，为了成功预测流入河口的水的特性，必须在架子上包括哪些物理学。这将允许改进未来的预测，由于在沿海海洋中的水的性质变化，在河口生态地球化学功能的变化。首席研究员和一名格拉德生将把拟议研究的结果直接与他们所在地区的利益相关者联系起来，并将结果传达给其他地区致力于理想社会成果的科学家。基于先前对沿海上升流、峡谷、河流羽流和河口交换流的广泛研究，部分理论框架已经存在。然而，在它到达河口之前，大陆架上的流入动态仍然相对未被探索，与河流羽流相比，观测证据少得多。双层流动的早期解析解将是一个关键的起点。将进行理想化的数值实验，以测试这组解决方案的假设力平衡和流入路径。数值实验中的力平衡将使用三种方法进行分析：（i）拉格朗日动量预算沿着流入粒子轨迹，（ii）向后的粒子跟踪，以有效地确定流入路径，（iii）平均密度（盐度）类，以分离纯粹的平流输送从需要混合。每一个都有优点和缺点，但结合起来，它们应该为推进理论提供明确的指导，特别是从两层到连续分层。在整个项目中，理论解释数值解的重要性质的能力将是成功的考验。

The physics controlling the source of waters flowing from the coastal ocean into the mouth of an estuary or fjord will be explored using theory and idealized numerical experiments. The specific goals are to develop theoretical predictions of the depth from which source water is drawn and the geographical region from which it is drawn. These two properties will be expressed as functions of controlling environmental variables. The parameter space will span a wide variety of systems, from shallow coastal plain estuaries on a gently sloping shelf, to deep fjords adjoining a shelf-crossing canyon. This research will inform numerical modelers about what physics must be included on the shelf in order to successfully predict the properties of water flowing into an estuary. This will allow improved future predictions of the change in estuarine biogeochemical function due to changing water properties in the coastal ocean. The principal investigator and a grad student will connect the results of the proposed research directly with stakeholders in their own region, and will communicate results to scientists working toward desired societal outcomes in other regions.Parts of a theoretical framework already exist, based on extensive previous work on coastal upwelling, canyons, river plumes, and the estuarine exchange flow. However the dynamics of the inflow on the shelf before it reaches the estuary remain relatively unexplored, with substantially less observational evidence than has been gathered for river plumes. Early analytical solutions for two-layer flow will be a key starting point. Idealized numerical experiments will be conducted to test the assumed force balance and inflow paths of this set of solutions. Force balances in the numerical experiments will be analyzed using three methods: (i) Lagrangian momentum budgets along inflow particle tracks, (ii) backward-in-time particle tracking to efficiently determine inflow pathways, and (iii) averaging in density (salinity) classes to separate purely advective transport from that requiring mixing. Each offers advantages and drawbacks, but in combination they should provide clear guidance for advancing the theory, particularly moving from two layers to continuous stratification. Throughout the project the ability of a theory to explain important properties of the numerical solutions will be the test of success.