RAPID: Evaluating Fine-Structure Estimates of Diapycnal Mixing from the DIMES 2010 Research Cruise

智力优势：昼夜混合(主要是垂直混合)在决定全球海洋的总体热量平衡和水质量分布方面发挥着关键作用。最好使用专门的微结构传感器测量昼夜扩散系数，这些传感器收集高垂直分辨率的测量结果。近年来，各种精细结构方法应运而生，成为微结构测量的廉价替代品。精细结构方法利用了电导率-温度-深度仪器(CTD)、降压式声学多普勒海流剖面仪(LADCP)和/或消耗性CTD(XCTD)的数据，所有这些数据都是在全球和所有季节例行收集的。因此，精细的结构方法似乎提供了在全球范围内绘制扩散系数的空间和时间变化的廉价地图的可能性。然而，与FINESTRUCTURE方法相关的误差预算仍然没有得到很好的表征。这一拟议的快速项目旨在通过促进微观结构和精细结构测量的详细相互比较来减少精细结构混合估计中的不确定性。36枚XCTD将在2010年1月至2月南大洋双星和异双星混合实验的研究巡航期间部署。该项目还将支持使用Thorpe标度和应变精细结构方法对XCTD测量进行分析，并与微结构估计以及为LADCP和CTD数据计划的类似基于剪切应变的精细结构分析进行比较。广泛影响：这项工作的结果将有助于社区越来越多地努力评估与评估海洋日周期混合的精细结构方法相关的不确定性。这些发现将在确定精细结构方法是否可以可信地用于绘制混合中的全球变化图方面发挥关键作用。结果应该允许评估最有效的精细结构方法的类型。由于该项目旨在为基于精细结构的全球扩散系数地图设定可用的误差界限，该项目的发现可能会对全球预测气候建模工作产生深远影响。此外，该项目还将有助于培养一名研究生。

Intellectual Merit: Diapycnal (mostly vertical) mixing plays a critical role in determining the overall heat budget and water mass distribution of the global ocean. Diapycnal diffusivities are best measured using specialized microstructure sensors, which collect measurements with high vertical resolution. In recent years a variety of fine-structure methods have emerged as inexpensive alternatives to microstructure measurements. Fine-structure methods take advantage of data from conductivity-temperature-depth instruments (CTDs), lowered acoustic Doppler current profilers (LADCPs), and/or eXpendable CTDs (XCTDs), all of which are routinely collected globally and through all seasons. Finestructure methods thus appear to offer the possibility of inexpensively mapping spatial and temporal variations in diffusivity on a global scale. However, the error budgets associated with finestructure methods remain poorly characterized. This proposed RAPID project is aimed at reducing the uncertainties in fine-structure mixing estimates, by facilitating a detailed inter-comparison of microstructure and fine-structure measurements. Thirty-six XCTDs will be deployed during the January-February 2010 research cruise of the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES). The project will also support analysis of the XCTD measurements using Thorpe scale and strain fine-structure methods and comparison with microstructure estimates and with similar shear-strain based fine-structure analyses planned for the LADCP and CTD data.Broader Impacts: Results of this work will contribute to a growing community effort to assess the uncertainties associated with fine-structure methods for evaluating diapycnal mixing in the ocean. These findings will play a critical role in determining whether fine-structure methods can plausibly be used to map global variations in mixing. Results should allow an assessment of the types of fine-structure methods that are most effective. Since the project aims to place usable error bounds on fine-structure based maps of global diffusivity, the findings from this project will potentially have a profound impact on global predictive climate modeling efforts. In addition, the project will contribute to the training of one graduate student.