Collaborative Research: Understanding mechanisms of projected 21st century ocean warming around Greenland

合作研究：了解格陵兰岛周围预计 21 世纪海洋变暖的机制

• 批准号: 1513396
• 负责人: Christopher Little
• 金额: $ 45.07万
• 依托单位: Atmospheric and Environmental Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1513396&HistoricalAwards=false
• 关键词: Collaborative; Research; Understanding; mechanisms; projected

Devastating storm surges result from a combination of the characteristics of the storm itself; e.g. wind strength, direction of storm approach to the coast, storm duration; and from preconditioning due to rising sea level, such that the storm waves can overtop protective barriers that provided adequate defense when sea level was lower. Water added to the oceans from melting glacier, ice caps, and ice sheets is a significant cause of sea level rise. In particular, the Greenland Ice Sheet is projected to be a major contributor to sea level rise during the present century. Much of the recently observed contribution is a response to warming ocean temperatures around Greenland, which cause marine-terminating glaciers to melt and calve icebergs into the ocean. Models that are used to predict this anticipated sea level rise exhibit a broad spread in ocean temperatures around the Greenland Ice Sheet, for reasons that are not well understood. This project is designed to improve understanding of the physical processes responsible for this spread in projected ocean temperatures amongst models.The lead principal investigator for this project, through his ongoing work with local and state governments, will ensure that the results are relevant to and transferred to planners and policy-makers. His parent company will assist in a similar information transfer to the private sector. The project will also contribute to workforce development through support for the training of a graduate student in state-of-the-art interdisciplinary science and through support of three early-career scientists during their formative years. The detailed mechanistic understanding provided by this work will reveal: the physical processes underlying the spread in CMIP5 projections of near-Greenland ocean warming; the nature and location of the surface fluxes driving warming; and the linkages between warming at different depths and different locations around the ice sheet. It will also provide a physical basis for linkages between near-Greenland ocean warming and other related Arctic climate system processes (e.g. Northern Hemisphere sea ice and the Atlantic Meridional Overturning Circulation). These linkages are vital to understanding how climate-driven changes in Greenland?s mass balance are coupled to other processes such as the loss of sea ice and more general polar surface warming. A two-part strategy will be used to evaluate causal physical mechanisms underlying the spread in CMIP5 projections of ocean warming in an efficient and detailed manner. Statistical analysis of ocean temperature will cluster AOGCMs by their ocean warming patterns and their co-variability (across space and models) with surface fluxes and other climate processes. Numerical simulations, forced by surface fluxes from a representative subset of CMIP5 models, will then be used to develop detailed oceanic heat budgets. Targeted perturbation experiments will isolate the role of atmospheric and Greenland meltwater flux in the context of widely varying CMIP5 representations of the Arctic freshwater budget.

毁灭性的风暴潮是风暴本身特征综合作用的结果；例如风力强度、风暴接近海岸的方向、风暴持续时间；以及由于海平面上升而进行的预处理，使得风暴波浪可以越过在海平面较低时提供足够防御的防护屏障。 冰川、冰盖和冰盖融化进入海洋的水是海平面上升的一个重要原因。 特别是，格陵兰冰盖预计将成为本世纪海平面上升的主要因素。 最近观察到的大部分贡献是对格陵兰岛周围海洋温度变暖的反应，这导致海洋终止冰川融化并将冰山崩解到海洋中。 用于预测海平面上升的模型显示，格陵兰冰盖周围的海洋温度存在广泛分布，但其原因尚不清楚。该项目旨在提高对模型中预测海洋温度传播的物理过程的理解。该项目的首席研究员通过与地方和州政府的持续合作，将确保结果与模型相关并转移规划者和政策制定者。 他的母公司将协助向私营部门进行类似的信息传输。 该项目还将通过支持对研究生进行最先进的跨学科科学培训以及对三名早期职业科学家在其成长阶段的支持，为劳动力发展做出贡献。 这项工作提供的详细机制理解将揭示： CMIP5 预测的近格陵兰海洋变暖传播背后的物理过程；导致变暖的地表通量的性质和位置；以及冰盖周围不同深度和不同位置的变暖之间的联系。 它还将为格陵兰岛附近海洋变暖与其他相关北极气候系统过程（例如北半球海冰和大西洋经向翻转环流）之间的联系提供物理基础。 这些联系对于理解气候驱动的格陵兰质量平衡变化如何与海冰消失和更普遍的极地表面变暖等其他过程耦合起来至关重要。 将采用由两部分组成的策略，以高效、详细的方式评估 CMIP5 海洋变暖预测中传播的因果物理机制。海洋温度的统计分析将根据海洋变暖模式及其与地表通量和其他气候过程的协变性（跨空间和模型）对 AOGCM 进行聚类。 然后，由 CMIP5 模型代表性子集的表面通量推动的数值模拟将用于制定详细的海洋热量预算。 有针对性的扰动实验将在北极淡水预算的 CMIP5 表示形式差异很大的背景下隔离大气和格陵兰融水通量的作用。