SGER: Turbulence Properties in the Mixed Layer/Thermocline Transition Layer

摘要 OCE-0721168本研究重点关注海洋上层过程，这些过程影响海洋近地表物理并控制海洋热量收支，从而调节全球气候和上层海洋营养通量，从而调节海洋生产和渔业。海洋混合层是海洋的最上面部分；这是一个强烈混合的区域，由风和波浪提供的湍流使温度和盐度的垂直分布均匀化至 O(100m) 的深度。在该层之下，在分层温跃层的上层中，湍流雷诺数要小几个数量级。尽管假设这两种状态之间的转变在混合层底部突然发生，但观察表明增强的湍流显着渗透到混合层正下方的分层水中。在这项研究中，佛罗里达州立大学的科学家将检查过去 20 年和低纬度和中纬度地区收集的现有湍流数据。这些数据允许直接估计过渡层中发生的扩散率和二密流。研究结果将揭示目前用于模拟全球气候数值模型中上层海洋湍流的参数化的适用性。 因此，这项研究将对这些用于预测对社会重要问题的模型产生广泛的影响。

Abstract OCE-0721168This study focuses on upper-ocean processes that impact the near-surface physics of the ocean and control the oceanic heat budget, which moderates global climate and the upper-ocean nutrient fluxes which moderate oceanic production and thus fisheries. The oceanic mixed layer is the uppermost portion of the ocean; it is a region of intense mixing where turbulence supplied by wind and waves homogenizes the vertical distribution of temperature and salinity down to depths of O(100m). Below this layer, in the upper layers of the stratified thermocline, turbulent Reynolds numbers are several orders of magnitude smaller. Although the transition between these two regimes is assumed to take place abruptly at the mixed-layer base, observations suggest that enhanced turbulence penetrates significantly into the stratified water just below the mixed layer. In this study, scientists at FSU will examine existing turbulence data collected during the past 20 years and low- and mid-latitude sites. These data allow for direct estimates of diffusivity and diapycnal flox occurring in the transition layer. The results will shed light on the suitability of parameterizations which are presently used to simulate upper ocean turbulence in numerical models of the global climate. Thus the study will have a broad impact on these models which are used in the prediction of issues that are important to society.