Collaborative Research: Using ocean data assimilation to explore Arctic/subarctic climate variability

合作研究：利用海洋数据同化探索北极/亚北极气候变化

• 批准号: 1233255
• 负责人: Michael Steele
• 金额: $ 10.93万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1233255&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; ocean; data

Intellectual merit: Recent decades have seen profound changes in higher latitude climate. This project addresses two goals responding to these changes. The first goal is to develop improved understanding of what past oceanic changes have occurred at high latitude during the past century through application of data assimilation to the sparse historical record of meteorological and oceanic measurements. The first task associated with this goal will be to improve the Simple Ocean Data Assimilation (SODA) data assimilation ocean reanalysis as a tool for high latitude research. This task builds directly on work funded by the predecessor to this grant. This special high latitude effort is required because of the complexities of the region?s topography, water masses and currents, the sparse, inhomogeneous oceanic and meteorological observational network, and the important role of sea ice and haline processes. The second task will be to explore the limits the historical data sampling and surface meteorology place on what can be learned about past climate variability through experiments testing the credibility of long ocean reanalyses.The second goal is to examine these results to explore the processes governing interaction between the high latitude ocean, the lower latitude ocean, and the overlying atmosphere, and how these interactions may contribute to climate variability. The remarkable warming the Nordic Seas and Arctic has experienced in the last decade bears similarity to a warm period in the 1920s-1930s. How similar are these two periods, both in magnitude and in impact on the subpolar North Atlantic and on the overlying atmosphere? On shorter decadal timescales the Atlantic Water flowing into the Nordic Seas shows substantial variability partially related to large-scale patterns in meteorology. Related to this are the anomalies of surface salinity such as the Great Salinity Anomaly. What is the origin of this variability, its relationship to the atmosphere, and what is its climate significance? Addressing this second goal will require exploring these mechanisms in coupled atmosphere/ocean/ice models, and in particular the new IPCC-class model runs, using the results of the assimilation studies as guidance. Coupled climate models have complete physics that allow the tracking of the movement of properties such as freshwater and heat through the climate system, while the comparisons to SODA and the historical observations provides information about the realism of the models.Broader impacts: This project will provide the scientific community with an improved analysis of past changes in the upper ocean temperature, salinity, and circulation at high latitude through development and dissemination of an improved SODA ocean reanalysis and improved understanding of its uncertainties. The project?s involvement in the Arctic Ocean Model Intercomparison Project and other venues will help promote the greater knowledge and use of ocean reanalyses generally, and SODA in particular. The second part of this research project, improving understanding of the role of oceanic basin exchanges is a process that needs to be understood in order to develop predictive models. The project will have a substantial educational component by making the data sets, analyses, and computer resources developed as part of this work freely available to the graduate students in the department.

学术价值：近几十年来，高纬度气候发生了深刻的变化。本项目针对这些变化提出了两个目标。第一个目标是通过对气象和海洋测量的稀少历史记录应用数据同化，更好地了解过去世纪在高纬度地区发生了哪些海洋变化。与这一目标有关的第一项任务是改进简单海洋数据同化（SODA）数据同化海洋再分析，作为高纬度研究的工具。这项任务直接建立在这项赠款的前身资助的工作基础上。这种特殊的高纬度努力是必要的，因为该地区的复杂性？海洋的地形、水团和海流、稀疏、不均匀的海洋和气象观测网络以及海冰和盐过程的重要作用。第二个任务是通过实验检验长期海洋再分析的可信性，探索历史数据采样和地面气象学对过去气候变化的限制。第二个目标是检验这些结果，探索高纬度海洋、低纬度海洋和上覆大气之间相互作用的控制过程，以及这些相互作用如何影响气候变化。北欧海洋和北极在过去十年中经历的显著变暖与20世纪20年代至30年代的温暖时期相似。这两个时期在强度和对副极地北大西洋和上层大气的影响方面有多相似？在较短的年代际时间尺度上，流入北欧海的大西洋水表现出相当大的变化，部分与大尺度气象模式有关。与此相关的是地表盐度异常，如大盐度异常。这种变化的起源是什么，它与大气的关系，以及它的气候意义是什么？实现这第二个目标将需要探索这些机制耦合大气/海洋/冰模式，特别是新的IPCC级模式运行，使用同化研究的结果作为指导。耦合气候模式具有完整的物理特性，可以跟踪诸如淡水和热量在气候系统中的运动，而与SODA和历史观测的比较则提供了关于模式真实性的信息。这一项目将为科学界提供一个更好的分析，通过发展和传播改进的SODA海洋再分析和提高对其不确定性的认识，项目？在北冰洋模式相互比较项目和其他场合的参与将有助于促进更多地了解和使用海洋再分析，特别是SODA。该研究项目的第二部分，提高对海洋盆地交换作用的理解是一个需要理解的过程，以便开发预测模型。该项目将有一个实质性的教育组成部分，使数据集，分析和计算机资源开发作为这项工作的一部分，免费提供给该部门的研究生。