SGER: An Exploratory Full-Depth Section of Mixing Observations Across the Arctic Ocean

已提供资金，以便在即将进行的2005年泛北极白令海考察期间，利用一种能够在具有挑战性的冰层覆盖条件下测量微尺度温度、传导率和速度切变的创新仪器，对整个北极海盆从表层到整个海洋深度的纵贯混合进行探索性调查。 微观结构测量结果将与来自降低的声学多普勒流速剖面仪和完整的水文-地球化学程序的信息一起进行分析。 将测量热方差和湍流动能的耗散率，并用于估计整个流域的垂直扩散率。拟议的测量是高度探索性的。 此外，微结构仪器及其探头非常敏感，增加了在冰层覆盖地区进行此类测量的不确定性和高风险。 如果成功的话，这些观测可能会在理解北冰洋的混合及其对热量，盐和动量的横向和垂直通量的影响方面取得重大飞跃。 理解和预测海洋对热量和淡水的吸收、储存和运输的一个关键问题是海洋内部密度表面的混合率。 这种混合是深层沃茨更新的先决条件，也是上层海洋热量转移和储存的必要条件。 理解这一关键过程最近变得更加紧迫，因为现在人们认识到，混合过程具有非常复杂的分布，与模型中假设的均匀混合速率完全不同。 一个特别重要的问题是了解那些控制北冰洋热量垂直通量的混合过程，从温暖的次表层沃茨到海面，热量可能导致海冰的损失，以及这些过程如何因全球变化而变化。

Funds are provided to conduct an exploratory investigation of diapycnal mixing across the entire Arctic basin from surface to full ocean depth using an innovative instrument capable of measuring microscale temperature, conductivity and velocity shear under challenging ice-covered conditions during the upcoming pan-arctic Beringia 2005 expedition. The microstructure measurements will be analyzed together with information from lowered acoustic Doppler current profiler and a full hydrographic-biogeochemical program. The dissipation rates of thermal variance and turbulent kinetic energy will be measured and used to estimate the vertical diffusivity across the whole basin. The proposed measurements are highly exploratory. Furthermore, microstructure instruments and their probes are very sensitive, adding to the uncertainty and high risk of such measurements in ice-covered regions. If successful, these observations may enable a significant leap forward in understanding of mixing in the Arctic Ocean and its influence on lateral and vertical fluxes of heat, salt and momentum. A key issue for understanding and predicting heat and freshwater uptake, storage and transport by the ocean is the rate of mixing across density surfaces in the ocean's interior. Such mixing is a prerequisite for the renewal of deep waters and is essential for upper ocean heat transfer and storage. Understanding this critical process has become more urgent of late, as it is now realized that mixing processes have very complex distributions, quite different from the uniform mixing rate assumed in models. One particularly important issue is understanding those mixing processes that control the vertical flux of heat, in the Arctic Ocean, from warm subsurface waters to the sea surface where the heat can contribute to the loss of sea ice, and how these might vary due to global change.