Collaborative Research: Asymmetric Circulation in Wind-Driven Bays

——Intellectual MeritA最近的分析模型预测，当盆地深度大于Ekman深度时，小型沿海盆地的风力环流基本上受地球自转的影响。旋转影响流体包轨迹的性质和复杂性，对混合和停留时间产生重要影响。将结合观测、分析和数值模拟来验证和扩展这一模型。2004-2005年冬季，将在墨西哥下加利福尼亚半岛加利福尼亚湾一侧的巴伊亚康塞普西翁进行实地观测。整个冬季，当海湾垂直混合良好时，海湾会受到强风的影响。观测将包括系泊仪器、船上调查和漂浮物部署，科学目标是：(a)通过观测描述在一个相对较深、混合良好、半封闭、暴露于强风的海湾中，旋转如何影响风力驱动的环流和与海洋的交换；(b)扩展分析模型，以表示潮汐和侧向密度梯度驱动的环流。用数值模型描述平流和垂直分层如何改变这种环流。更广泛的影响小型沿海盆地（海湾、河口、泻湖）的生态和社会重要性与其规模不成比例。在其他生态功能中，泻湖和河口是鸟类迁徙的中转站，是动植物的苗圃，也是某些海洋哺乳动物交配和产仔的场所。与此同时，这些水体也受到了人为活动的深刻影响。通过对控制这些盆地环流和与海洋交换的过程进行动态描述，本研究将通过基于科学的管理和工程实践，帮助最大限度地减少人类的影响，如污水排放。此外，该项目代表了与墨西哥科学家的国际合作，支持两名研究生。其中一名pi是一个代表性不足的群体的成员。这项研究还将让本科生，包括少数族裔，参与研究。

---Intellectual MeritA recent analytical model predicts that the wind-driven circulation in small coastal basins is fundamentally influenced by the Earths rotation when the basin depth is greater than the Ekman depth. Rotation affects the character and complexity of fluid parcel trajectories, with important consequences for mixing and residence times. A combination of observations and analytical and numerical simulations will be conducted to verify and extend this model. Field observations will be done during the winter season 2004-2005 in Bahia Concepcion, on the Gulf of California side of the Baja California peninsula in Mexico. The bay is subject to strong wind forcing throughout the winter, when it is vertically well mixed. The observations will include moored instrumentation, shipboard surveys and drifter deployments and the scientific objectives are:(a) to describe through observations how rotation affects the wind-driven circulation and the exchange with the ocean in a relatively deep, well-mixed, semi-enclosed bay that is exposed to strong winds, and(b) to extend the analytical model to represent the circulation driven by tides and by lateral density gradients, and to describe with numerical models how advection and vertical stratification modify this circulation. Broader ImpactsThe ecological and societal importance of small coastal basins (bays, estuaries, lagoons) is out of proportion with their size. Among other ecological functions, lagoons and estuaries serve as way stations for bird migration, as nurseries for fauna and flora and as mating and calving grounds for certain marine mammals. At the same time these water bodies have been deeply impacted by anthropogenic activities. By developing a dynamical description of the processes that control circulation in these basins and exchange with the ocean, this study will help minimize human impacts such as sewage discharge through science-based management and engineering practices. In addition, this project represents international collaboration with Mexican scientists, supports two graduate students. One of the PIs is a member of an underrepresented group. The study will also expose undergraduates, including minority groups, to research.