CAREER: Fluxes and Structures in Double-Diffusive Convection

在过去几年中，双扩散混合对于水团转换和确定所有海洋的温-盐关系结构的重要性日益明显。双扩散对流最有趣的方面之一是它能够将光滑的垂直梯度转化为由薄分层界面隔开的混合层组成的阶梯结构。来自热带大西洋的最新现场数据表明，与具有类似层结的非阶梯区域相比，温盐阶梯内盐指造成的垂直通量显著增加(数量级)。(Schmitt等人，2005年)。因此，提高我们对温盐阶梯的形成、演化和大尺度后果的认识是至关重要的。在这个职业奖项中，海军研究生院的一名研究人员将量化平滑坡度和温盐楼梯中的双扩散传输，以更清楚地了解楼梯的起源，并详细说明提供信息的条件。这项工作将包括数值过程建模和理论分析相结合。理论和模型运行的推论将被用来解释海洋细微结构数据和实验室实验的结果。这项研究的结果将解决关于温盐阶梯的动力学、热和盐混合速率的大小以及它们随环境参数的变化的争议。主要研究人员新发展的理论将引用混合层的厚度和由此产生的昼夜通量，将被探索。除了这项工作的智力价值外，拟议的教学活动将针对海军研究生院的学生，通过开发一门专题课程、扩大远程学习计划并为几名研究生提供建议，使他们接触到海洋微结构的物理。

The significance of double-diffuse mixing for water-mass transformation and determining the structure of the temperature-salinity relationship in all oceans is becoming increasingly clear over the last few years. One of the most intriguing aspects of double-diffuse convection is related to its ability to transform smooth vertical gradients into the stepped structures consisting of mixed layers separated by thin stratified interfaces. Recent field data from the tropical Atlantic has shown that vertical fluxes due to salt fingers within thermohaline staircases are significant (by order of magnitude) enhanced over non-staircase regions with similar stratifications. (Schmitt et al., 2005). Thus, it is vital to improve our understanding of the thermohaline staircase formation, evolution and the large scale consequences. In this CAREER award, a researcher at the Naval Postgraduate School will quantify the double-diffusive transport in both smooth gradients and thermohaline staircases, developing a clearer insight into the origin of staircases and specifying the conditions for their information. The work will involve a combination of numerical process modeling and theoretical analysis. Inferences from the theory and model runs will be used to interpret the oceanic fine-and microstructure data and results of the laboratory experiments. The results from this study will resolve the controversy with regard to the dynamics of the thermohaline staircases, the magnitude of the heat and salt mixing rates, and their variation with environmental parameters. The newly developed theory by the principle investigator will invoke the thickness of the mixed layers and the resulting diapycnal fluxes, will be explored. In addition to the intellectual merit of the work, the proposed teaching activities will target the Naval Postgraduate School students and expose them to the physics of the ocean microstructure by developing a special topics course, expanding the distance learning program, and advising several graduate students.