Ocean convection and mixing: from signature to parameterization

我请求支持继续研究海洋混合和水团交换的动力学。我的主要兴趣在于，由于模型分辨率较低，无法通过数值模型直接处理的关键现象。为了对海洋和气候系统进行可靠的数值模拟，需要对这种现象进行基于动态的参数化。 在资助期间，我的研究计划将建立在两个具有极大科学兴趣和实际重要性的主题上，一个与西北航道的冰有关，另一个与斯科特大陆架上的水团相互作用有关。这项工作将与学生一起进行，计划与渔业和海洋部合作伙伴的密切合作将极大地促进毕业生的职业潜力。 主题1：受冰影响区域的对流热通量 我的研究小组将利用部署在巴罗海峡的先进剖面仪获得的细微尺度特征，研究海洋湍流和对流对沿海水域冰盖的影响。这是在西北航道，所以一个关键的初始目标将是改进对冰盖周期的统计预测，这是航行的一个主要因素。通过在整个水柱中加入签名，该方法将改进以前使用逐点测量的预测。然而，改善涉及的不仅仅是统计能力。我们还将应用湍流文献中的结果来推断热通量，并应用对流文献中的结果来推断冰的转变。另一个目标是将这些东西与背景状态联系起来，开发更可靠的对研究区域冰盖的预测。这项工作将为改进用于一般受冰影响地区的模型的参数化铺平道路。 主题2：利用基于滑翔机的仪器推断侧向交错 海洋滑翔机越来越多地被用来观察沿海水域。它们的锯齿形剖面运动产生了高空间采样密度，揭示了传统船基调查难以解决的海洋变化。我们将利用这一增强的分辨率来研究斯科特陆架上的细微尺度锋面特征，特别是由准横向交错引起的跨锋交换。我在过去几年进行的滑翔机调查试验表明，对交错运动和相关的水文变化进行足够详细的跟踪是可行的，以改善对跨锋面交换的参数化的动力学约束。这一结果将加深对有关新斯科舍省洋流的水如何与墨西哥湾流产生的水相互作用的重要问题的理解。取样和分析方法方面的预期进展也将有利于对水团碰撞的许多其他沿海地区的研究。

I request support for continuing research on the dynamics of ocean mixing and watermass exchange. My main interest is in key phenomena that cannot be handled directly by numerical models, owing to coarse model resolution. Dynamically-based parameterizations of such phenomena are needed for reliable numerical simulation of the ocean and climate system. Over the funding period, my research program will build on two themes of great scientific interest and practical importance, one related to ice in the Northwest Passage and the other to watermass interactions on the Scotian Shelf. The work will be carried out with students, and the planned close collaboration with partners in Department of Fisheries and Oceans should contribute greatly to the career potential of the graduates. Theme 1: convective heat fluxes in ice-influenced domains My research group will study the effects of ocean turbulence and convection on ice cover in coastal waters, using fine-scale signatures acquired with an advanced profiling instrument deployed in Barrow Strait. This is in the Northwest Passage, so a key initial objective will be to improve on statistical predictions of the periods of ice cover, a prime factor for navigation. By incorporating signatures throughout the water column, the methodology will improve upon previous predictions using point-wise measurements. However, the improvement involves more than mere statistical power. We will also apply results from the turbulence literature to infer heat fluxes, and results from the convection literature to infer ice transformation. Another objective is to relate these things to the background state, to develop more robust predictions of ice cover in the study region. This work will pave the way to improved parameterizations for use in models of general ice-affected regions. Theme 2: inference of lateral interleaving with glider-based instrumentation Ocean gliders are used increasingly to observe coastal waters. Their zigzag profiling motion yields high spatial sampling densities that reveal ocean variations that are difficult to resolve with conventional ship-based surveys. We will take advantage of this enhanced resolution to examine fine-scale frontal features on the Scotian Shelf, with a particular focus on cross-frontal exchanges caused by quasi-lateral interleaving. My tests with glider surveys carried out over the past few years suggest the feasibility of tracking interleaving motions and associated hydrographic changes in sufficient detail to provide improved dynamical constraints on parameterizations of cross-frontal exchange. The results will deepen understanding of important issues relating to how the waters of the Nova Scotia current interact with waters derived from the Gulf Stream. The anticipated advances in sampling and analysis methodologies will also benefit studies of the many other coastal regions in which watermasses collide.