SODA4: ocean climate variability at mesoscale resolution

海洋观测稀疏，在空间或时间上分布不均匀。由于许多分析受益于规则网格上的完整字段，因此已开发了再分析产品，通过使用可用观测值约束数值模式来填补这一空白。最广泛使用的海洋再分析产品之一是简单海洋数据同化。 目前的SODA 3分辨率不足以捕捉大部分涡旋，特别是在高纬度地区。这可能会在存在强涡流活动或风强迫和混合的区域造成偏差。该项目利用计算能力的增长，更好地利用有限的历史观测记录，使用一个模型，解决占主导地位的较小尺度的运动，以产生一个中尺度解决全球海洋/海冰再分析称为SODA 4。该项目还包括重点审查中尺度过程在北极和次极地/北极交换中的作用。这项工作旨在了解海洋和海冰系统在调节和改变地球天气和气候方面的作用，部分作为改善未来变化预测的指导。 加深对历史海洋变异性的了解有利于科学事业，因为它可以发挥关键作用，指导改进对耦合气候变异性的预测，并通过重建其流域规模的背景，增加历史观测记录的额外价值。 通过支持开发和分发跨越过去四十年的更现实的历史气候再分析，该项目可以整合多个领域和学科的研究活动。 更好地表示较小尺度的运动和人类影响较大的区域，如近岸环境，也有助于向广大社区（沿海规划者和工程师、风电场、渔业社区等）提供信息。关于历史上海洋的变化和变化。该研究项目也以多种方式服务于马里兰州大学帕克分校的教育使命。 最直接的是，它将支持大气和海洋科学系一名研究生的论文研究。 对SODA 3结果的检验表明，在中尺度变率和近地面底辟过程占主导地位的地方，其分辨率是不够的。 该项目探讨了对海洋/海冰系统状态表示的进一步改进，即使在没有中尺度分辨观测系统的几十年中，也可以通过更完整地表示海洋中尺度过程来获得。 北冰洋及其与次极地环流的连接将受益于更高的分辨率。次极地北大西洋是与北冰洋进行水交换的主要途径，由于许多原因，这种联系特别令人感兴趣。 首先，北欧海的表层水正在迅速变暖，冬季冰正在消退。 第二，强烈的年代际温度变率存在，对北极中部的影响未知。 三是深水形成的关键区域。 因此，该项目包括一个集中的努力，以提高代表性和诊断的动力学的亚极地/北极交换及其连接到可变的北冰洋watermass.This奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。

Oceanographic observations are sparse and not uniformly distributed over space or time. Since many analyses benefit from complete fields available over a regular grid, reanalysis products have been developed to fill this gap by constraining a numerical model with available observations. One of the most widely used ocean reanalysis products is the Simple Ocean Data Assimilation. Its current version (SODA3) does not have sufficient resolution to capture most of the eddies, especially in the high latitude regions. This may cause biases in regions where strong eddy activity or wind forcing and mixing are present. This project exploits the growth of computational power to make improved use of the limited historical observational record using a model that resolves the dominant smaller scales of motion in order to produce a mesoscale resolving global ocean/sea ice reanalysis called SODA4. The project also includes a focused examination of the role of mesoscale processes in the Arctic and in subpolar/Arctic exchanges. This work is directed toward understanding the role the ocean and sea ice systems play in regulating and modifying Earth’s weather and climate partly as a guide to improve forecasts of future changes. Improved understanding of historical ocean variability benefits the scientific enterprise by playing a crucial role as a guide to improve forecasts of coupled climate variability and by adding additional value to the historical observational record by reconstructing their basin-scale context. By supporting development and distribution of more realistic historical climate reanalysis spanning the past four decades this project can serve to integrate research activities across multiple areas and disciplines. The improved representation of smaller scales of motion and of regions of high human impact such as the nearshore environment should also help inform a broad community (coastal planners and engineers, wind farms, the fisheries community, etc.) regarding historical ocean variability and change. This research project also serves educational mission of University of Maryland College Park in several ways. Most directly it will support the dissertation research of a graduate student at the Department of Atmospheric and Oceanic Science. It will also involve a number of undergraduate research projects.Examination of SODA3 results shows that its resolution is insufficient where mesoscale variability and near-surface diapycnic processes play dominant roles. This project explores the additional improvements to representation of the state of the ocean/sea ice system that can be gained by more completely representing oceanic mesoscale processes even during decades when mesoscale-resolving observing systems were not available. One region which will benefit from enhanced resolution is the Arctic Ocean and its connection to the subpolar gyres. The subpolar North Atlantic is the major route by which water is exchanged with the Arctic Ocean and this connection is of particular interest for many reasons. First, the surface water of the Nordic Seas is warming rapidly and the winter ice is retreating. Second, strong decadal temperature variability is present with unknown consequences for the central Arctic. Third it is a key region of deepwater formation. This project thus includes a focused effort to improve representation and diagnosis of the dynamics of subpolar/Arctic exchanges and their connection to variable Arctic Ocean water masses.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.