OPP-PRF: The Marginal Ocean Zone: Definition, Dynamics, and Implications for a Changing Arctic Ocean through Model-Observation Synthesis

北冰洋是世界海洋中变化最快的地区之一。具体来说，冬季海冰覆盖而夏季没有海冰覆盖的“季节性冰带”正在扩大。随着这一区域的扩大，影响海洋运动和海洋特性（如温度、盐度和分层）的物理过程正在发生变化。这些变化的物理影响着净初级生产力、空气-海洋气体交换，以及向营养级上升的过程，包括影响土著社区、当地渔业和全球航运模式。然而，对这一地区的海洋进行测量是一项挑战。这项研究将结合所有可用的数据来确定造成季节性冰带海洋运动和性质的重要物理过程。这将促进目前对冰缘附近海洋动力学的理解，从而将影响目前对与北冰洋和海冰变化有关的一系列跨学科主题的理解。人们已经做了大量的工作来描述季节性冰带的一个子区域，即边缘冰带，它代表了15%冰浓度等高线内的区域。然而，这个定义是以冰为中心的。这个项目将从海洋的角度来解决这个问题。研究人员假设存在边缘洋带，这是一个海洋区域，与边缘冰带和开放海洋都表现出不同的动力学。本研究将对北冰洋这一区域的水文条件进行跨时空尺度的表征。具体来说，该项目将综合所有可用数据，根据海洋特性（如温度、盐度和分层）得出边缘海洋区域的通用定义。然后，该项目将量化边缘海洋区域内属性的季节性演变以及这些动态的区域差异。随后，该项目将量化天气尺度过程和大气强迫对混合层动力学的重要性，以及对边缘海洋区的热量和淡水含量的重要性。北冰洋内部的长期变化正在影响环流模式、动力和气候尺度反馈。这项工作将诊断、量化和解释边缘洋区内的长期变化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Arctic Ocean is one of the most rapidly changing regions of the World Ocean. Specifically, the Seasonal Ice Zone, which is the area covered by sea ice in winter but not in summer, is growing. As this area grows, the physical processes that influence ocean motion and ocean properties like temperature, salinity, and stratification are changing. These changing physics influence net primary productivity, air-sea gas exchange, as well as processes up the trophic levels, including impacting native communities, local fisheries, and global shipping patterns. However, it is challenging to take measurements of the ocean in this region. This research will combine all available data to determine the important physical processes responsible for ocean motion and properties in the Seasonal Ice Zone. This will advance current understanding of ocean-dynamics in the vicinity of the ice edge, and thus will influence current understanding on a host of interdisciplinary topics related to Arctic Ocean and sea ice change.Significant work has been done to characterize a sub-region of the Seasonal Ice Zone known as the Marginal Ice Zone, which represents the region within the 15% ice concentration contour. This definition, however, is ice-centric. This project will approach the question from an ocean perspective. The researchers hypothesize the existence of the Marginal Ocean Zone, a region of the ocean which exhibits distinct dynamics from both the Marginal Ice Zone and the open ocean. This research will characterize the hydrographic conditions across spatio-temporal scales in this region of the Arctic Ocean. Specifically, the project will synthesize all available data to derive a universal definition for the Marginal Ocean Zone based on ocean properties like temperature, salinity, and stratification. This project will then quantify the seasonal evolution of properties within the Marginal Ocean Zone as well as the regional differences in these dynamics. Subsequently, the project will quantify the importance of synoptic scale processes and atmospheric forcing on the mixed layer dynamics, as well as on the heat and freshwater content of the Marginal Ocean Zone. Long-term changes within the Arctic Ocean are influencing circulation patterns, dynamics, and climatic-scale feedbacks. This work will diagnose, quantify, and explain long-term changes within the Marginal Ocean Zone.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.