Experimental Investigation of Differential Diffusion in Low Buoyancy Reynolds Number Oceanic Regimes

[136116] MoumA将在深海区域收集拖曳微结构仪器MARLIN的标量梯度光谱的综合测量数据，这些区域预计会有大范围的湍流和分层制度。本研究的目的是探讨盐扩散率与热扩散率之比与浮力雷诺数的关系。为了实现这些目标，将在MARLIN上建造和部署两个新的传感器，这些传感器使用的是人们熟知的原理。第一种是结合热电偶/微尺度电导率探头。第二种是使用多个热电偶对的各向异性探针。分析水平标量波动的一个补充目的是改进微观结构测量的解释。通常会做出许多假设，以从一维、部分分解的标量谱推断混合和通量，或将标量谱与湍流动能耗散率联系起来（例如各向同性假设、标量梯度的通用谱形式和相关常数）。结合现有的垂直光谱目录和湍流模拟的光谱，这些测量将提高微观结构群落可靠量化小尺度海洋过程影响的能力。

0136116 MoumA comprehensive set of measurements of scalar gradient spectra from the towed microstructure instrument MARLIN, will be collected in regions of the abyssal ocean where a large range of both turbulence and stratification regimes is expected. The purpose of the study is to investigate the dependence of the ratio of salt diffusivity to heat diffusivity on buoyancy Reynolds number. To accomplish these objectives, two new sensors using well understood principles will be built and deployed on MARLIN. The first is a combined thermocouple/microscale conductivity probe. The second is an anisotropy probe using multiple thermocouple pairs. A complementary purpose for analyzing horizontal scalar fluctuations is to improve the interpretation of microstructure measurements. Many assumptions are commonly made to infer mixing and fluxes from one-dimensional, partially resolved scalar spectra, or to relate scalar spectra to turbulent kinetic energy dissipation rates (such as the assumption of isotropy, a universal spectral form for scalar gradients, and associated .constants). Used in conjunction with the present catalog of existing vertical spectra and spectra from turbulence simulations, these measurements will permit improvements in the ability of the microstructure community to reliably quantify the effects of small scale ocean processes.