CAREER: Benthic Boundary Mixing and Dissolved Oxygen Transfer at the Sediment Water Interface in a Stratified Lake

申请号：CTS-9703451首席研究员：Hondzo这是一项CAREER资助，用于研究热分层湖泊中的底栖生物边界混合。将在五个淡水湖进行实地测量。底栖边界层的湍流特性将使用一个带有声学多普勒测速仪的自包含微剖面仪进行研究。用热敏电阻链测量湖盆内波特性。几个问题将被解决，如：(1)在倾斜边界层内产生湍流的主要机制；(2)底栖边界层内上坡体积通量的大小和相关的循环时间尺度。(3)确定湍流边界层厚度是由湍流娱乐决定，还是由倾斜边界附近的内波特性决定。(4)底栖边界层内垂直涡动扩散系数是否与整个湖泊的动态稳定性（湖数）相关？实验室实验将重点关注沉积物-水界面气体传递机制的细节。近床液体湍流和溶解氧（DO）浓度也将在实验室通道中在广泛的雷诺数范围内测量，用于各种底部沉积物。结合近床湍流特性的DO微剖面的确定将解决有关DO分布的广泛问题。研究结果将为验证现有的概念模型提供机会，并促进新模型的开发，从而提高我们预测湖泊、水库和沿海水域水质和运输相关参数的能力。

ABSTRACT Proposal Number: CTS-9703451 Principal Investigator: Hondzo This is a CAREER grant to study benthic boundary mixing within thermally stratified lakes. Field measurements will be conducted in five freshwater lakes. Turbulent properties of the benthic boundary layer will be investigated using a self-contained microprofiler augmented with the acoustic Doppler velocimeter. The internal wave characteristics within the lake basin will be measured with thermistor chains. Several issues will be addressed such as: (1) The primary mechanism for generating turbulence within the sloping boundary layer (2) The magnitude of the up slope volume flux and associated cycling time scales within the benthic boundary layer. (3) Determination of whether the turbulent boundary layer thickness is determined by the turbulent entertainment or by the internal wave characteristics near the sloping boundaries. and (4) Whether the vertical eddy diffusivity within the benthic boundary layer can be correlated with the dynamic stability (Lake Number) of the entire lake? Laboratory experiments will focus on the details of the interfacial gas transfer mechanism at the sediment-water interface. Near-bed liquid turbulence and dissolved oxygen (DO) concentrations will be also be measured in a laboratory channel over a wide range of Reynolds number, for a variety of bottom sediments. The determination of DO microprofiles in conjunction with characterization of near-bed turbulence will address a wide range of questions concerning the distribution of DO. The research results will provide an opportunity to validate the existing conceptual models, as well as enhance the development of new models which can improve our ability to predict water quality and transport related parameters in lakes, reservoirs, and coastal waters.