Collaborative Research: Asymmetric Circulation in Wind-Driven Bays

-Knowledge Merita最近的分析模型预测，当盆地深度大于Ekman深度时，沿海小盆地的风生环流基本上受到地球自转的影响。旋转影响液体颗粒轨迹的性质和复杂性，对混合和停留时间有重要影响。将进行观测以及分析和数值模拟相结合的方法来验证和推广该模型。2004-2005年冬季期间，将在墨西哥下加利福尼亚半岛加利福尼亚州海湾一侧的巴伊亚康塞普西翁进行实地观测。整个冬天，当海湾在垂直方向上很好地混合时，它受到强风的影响。观测将包括系泊仪器、船上测量和漂流物部署，科学目标是：(A)通过观测说明旋转如何影响风驱动的环流以及在一个相对较深、混合良好、半封闭、有强风的海湾中如何影响风驱动环流以及与海洋的交换；(B)扩展分析模型，以说明潮汐和横向密度梯度驱动的环流，并用数值模型描述平流和垂直层结如何改变这种环流。更广泛的影响沿海小流域(海湾、河口、泻湖)的生态和社会重要性与它们的大小不成比例。在其他生态功能中，泻湖和河口是鸟类迁徙的中转站，是动植物的托儿所，也是某些海洋哺乳动物的交配和产卵场所。同时，这些水体也深受人类活动的影响。通过对控制这些盆地中的循环并与海洋进行交换的过程进行动态描述，这项研究将有助于通过基于科学的管理和工程实践将污水排放等人类影响降至最低。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是代表人数不足的团体的成员。这项研究还将使本科生，包括少数族裔群体，接触到研究。

---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.