Collaborative Research: Understanding Arctic System Change Through Synthesis of Hydrographic and Sea Ice Observations from the early 21st Century

自本世纪之交以来进行的观察表明，北极的物理环境和相关生态系统正在发生显著变化，为了预测未来的变化，我们需要能够量化北极气候的多变性和变化在多大程度上与海洋环流有关，海冰的分布如何对气候模型预测的北极变暖作出放大的反应，以及初级生产力、物种分布和相关的生态系统结构将如何随着北极国家的演变而变化。我们对这些过程的驱动机制的理解取决于我们对北极系统的了解，以及我们以与观测一致的方式模拟其时间演变状态的能力。该项目将采用一种综合海洋观测的先进方法，以开发一种建立对北极系统的基线了解的工具。拟议研究的成果将包括更好地量化北极系统自世纪之交以来的变化，以及更好地理解这些变化的动力原因。由此产生的海洋和海冰性质的分析领域很可能在未来的研究中被社区广泛利用。该项目将把从船舶、飞机和自主仪器获得的水文观测、来自现场浮标、卫星和载人船只的海冰数据以及状态估计基础设施内的边界层气象学结合在一起，以对北冰洋在大约21世纪第一个十年期间的演变作出物理和动力学描述。利用不断扩大的观测数据库，该项目的两个主要目标是：利用2002年至今的伴随北极次极地涡旋状态估计，对所有现有的北极水文和海冰观测建立动态一致和全面的综合；利用综合产品对推动北极系统演变的物理机制进行科学调查。该小组将量化四个关键科学问题：上层海洋水文和环流的时间平均、季节周期和年际变化；北冰洋热量和淡水(FW)含量的年际变化；海冰状态和气海通量的变化；以及北极和亚极地涡旋之间的联系，重点是热量和FW交换和反馈。所产生的产品将是北冰洋、其邻近海域和北大西洋次极地的时间平均、平均季节周期和时变量的全套变量，这些变量表征了海-海耦合的物理冰态、热量、FW、动量和涡度收支，以及推断的海-气通量和时间-平均海洋湍流混合。这些产品将向研究人员和学生、政策制定者、行业和普通公众提供。将与麻省理工学院博物馆合作开展一项实质性的外联活动，以汇集各种多媒体项目，利用科学成果，包括本项目的成果，直观地描述北冰洋正在发生的重大变化。其目标是让对多媒体项目感兴趣的广大受众利用实际的科学数据集在这两种观点之间建立切实的联系。计划举办展览和配套活动，目的是制作可随时用于更广泛传播的材料。该项目将支持两名女性早期职业科学家。

Observations made since the turn of this century indicate that the Arctic physical environment and associated ecosystems are undergoing remarkable changes and to predict future changes we need to be able to quantify how much of Arctic climate variability and change is linked to the ocean circulation, how the distribution of sea ice responds to the amplified Arctic warming predicted by climate models, and how primary productivity, species distributions and associated ecosystem structures will change with the evolving Arctic state. Our understanding of the driving mechanisms for these processes depends on our knowledge of the Arctic system and our ability to simulate its time-evolving state in a way that is consistent with observations. This project will employ an advanced approach for synthesizing oceanographic observations to develop a tool that establishes a baseline understanding of the Arctic system. Outcomes of the proposed research will include better quantification of the Arctic system's changes since the turn of the century, and improved understanding of the dynamical causes for these changes. It is likely that the resulting analyzed fields of ocean and sea ice properties will be widely utilized by the community in future research. This project will bring together hydrographic observations obtained from ship, aircraft and autonomous instruments, sea ice data from in situ buoys, satellites and manned vessels, and boundary-layer meteorology within a state estimation infrastructure to develop a physical and dynamical description of the evolving Arctic Ocean during roughly the first decade of the 21st century. Taking advantage of a growing observational database, the project's two main objectives are: the creation of a dynamically-consistent and comprehensive synthesis of all available Arctic hydrographic and sea ice observations using the adjoint-based Arctic Sub-polar gyre sTate Estimate for the period 2002-present; and scientific investigations, using the synthesis products, of physical mechanisms driving the evolving Arctic system. The team will quantify four key science issues: the time-average, seasonal cycle, and interannual variability of the upper-ocean hydrography and circulation; the interannual changes in Arctic Ocean heat and freshwater (FW) content; changes in the sea ice state and air-sea fluxes; and connections between the Arctic and the Sub-polar gyre, focusing on heat and FW exchanges and feedback. Products generated will be the time-mean, mean seasonal cycle, and time-varying quantities in the Arctic Ocean, its neighboring seas and sub-polar North Atlantic of the full set of variables characterizing the coupled physical ocean-sea ice state, heat, FW, momentum and vorticity budgets, and inferred air-sea fluxes and time-mean oceanic turbulent mixing. These products will be made available to researchers and students, policy makers, industry, and the general public. A substantial outreach activity will be undertaken, in collaboration the MIT Museum, to assemble diverse multimedia projects that use scientific results, including those from this project, to visualize changes due to ongoing major shifts in the Arctic Ocean. The goal is to engage the general audience interested in the multimedia projects with actual scientific datasets to establish tangible links between the two perspectives. Exhibitions and accompanying events are planned with a goal of creating material that may be readily used for broader dissemination. The project will support two female early career scientists.