Pycnocline Mixing in Shelf Seas

大陆架海在河口和海洋之间提供了一个过渡区，碳、营养物质、沉积物和污染物可以通过这个过渡区进行交换。欧洲西北部大陆架的潮流和混合主要由与海床相互作用的潮汐控制，密度分层发生在夏季，覆盖该地区约80%的地区。这些地区的生物初级生产水平很高。然而，通过层化流体的这些临界界面的营养物质和碳的交换知之甚少，在数值模型中也是如此。该项目旨在汇编世界上最大的陆架海跃层湍流和水文测量观测数据库，并利用最先进的计算机模拟和新的观测技术来调查、量化和参数化负责跨越该临界界面的通量的物理机制和过程。特别是，我们将对切变不稳定促进的跃层湍流和混合有更好的理解。我们将测试假设，这些机制，或机制之间的相互作用，驱动跃层切变到超过一个临界阈值的水平，超过这个临界值，就会出现灾难性的稳定性损失，导致幕式混合。将开发和测试这种混合的参数。

The continental shelf seas provide a transition zone between estuaries and the ocean across which carbon, nutrients, sediments and contaminants are exchanged. The currents and mixing on the NW European continental shelf are dominated by the tide interacting with the sea bed, with density stratification occurring during summer months across ~80% of the region. Significant levels of biological primary production occur in these regions. However, the exchange of nutrients and carbon across these critical interfaces of stratified fluid is poorly understood and so is poorly represented in numerical models.This project aims to compile the world's largest observational data base of shelf sea pycnocline turbulence and hydrographic measurements and to exploit state-of-the-art computer modelling and new observational technology to investigate, quantify, and parameterise the physical mechanisms and processes responsible for the fluxes across this critical interface. In particular we will develop improved understanding of pycnocline turbulence and mixing promoted by shear instability. We will test the hypothesis that these mechanisms, or interaction between mechanisms, drives pycnocline shear to levels which exceed a critical threshold beyond which there is a catastrophic loss of stability resulting in episodic mixing. Parameterisations for this mixing will be developed and tested.