Collaborative Research: Understanding the role of Arctic cyclones - A system approach

合作研究：了解北极气旋的作用 - 系统方法

• 批准号: 1603384
• 负责人: John Cassano
• 金额: $ 66.66万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1603384&HistoricalAwards=false
• 关键词: Collaborative; Research; Understanding; role; Arctic

Arctic cyclones are an important contributor to sea ice deformation and oceanic mixing. Changes
in storm activity, and associated atmospheric feedbacks, have been linked to increased seasonality of the high north in the last decade, and with sea ice depletion during summer months. Cyclones are also likely to respond to changes in Arctic ice cover and ocean state indicating that
the atmosphere-ocean-ice system is tightly coupled through processes related to cyclones. Previous Arctic modeling studies typically used regional model simulations without full coupling
of the atmosphere-ocean-ice system, or fully coupled global climate models that do not permit year-on-year comparison with the observational record. This study will avoid such limitations by using
the Regional Arctic System Model (RASM), for which output corresponds directly with month-on-month observational records. This
will allow assessment of the ice-ocean-atmosphere coupling processes on multiple temporal
and spatial scales, and to relate them to limited Arctic Ocean measurements to build a more complete understanding of how increased cyclone activity may be helping to shift the surface climate of the Arctic to a new, warmer state with seasonal sea ice cover, and of how cyclones
will respond to this new Arctic Ocean state. The impact of cyclones on Arctic stakeholder sectors in northern and western Alaska, including coastal communities and marine transport, will be assessed through a partnership with the Alaska Center for Climate Assessment and Policy and the project's inventory of Arctic cyclones and associated ocean and sea ice conditions will be archived at the National Snow and Ice Data Center. Historical time series of annual and seasonal Arctic cyclone activity, maps of tracks and intensities of Arctic cyclones, and case studies of intense or impactful cyclones will be made available on a project web page. The project will engage graduate students and a post-doctoral fellow,
and results will be used in atmospheric and oceanic science undergraduate and graduate level courses at the project institutions. Outcomes from this work will be address priorities in the US National Strategy for the Arctic Region and will address key uncertainties in understanding extreme events and their role in the Arctic climate system. The recent loss of Arctic sea ice has increased the potential for ocean-atmosphere coupling
in the Arctic, especially in areas of low ice concentration or where the ice edge has receded. An important aspect of increased ocean-atmosphere Arctic coupling is the
 potential increase
of the ocean's response to storms. Where once mitigated by thick ice, wind-induced ice deformation and oceanic mixing are increasing as the ice pack thins. The decreasing Arctic ice cover and associated warming of the Arctic Ocean may also impact cyclone intensity and frequency. This grant will support investigation of changes in atmosphere-ice-ocean coupling in the presence of cyclones in the Arctic. It will advance our understanding of coupled atmosphere-ocean-ice processes with a focus on the role and response of cyclones in altering the state of the Arctic system. A cyclone tracking scheme will be applied to reanalyses, yielding an inventory of Arctic cyclone locations, tracks, and intensities that will provide a framework for analysis of ice and upper-ocean responses to storms. The responses of ice concentration, ocean temperature and salinity, and associated ice mass balance before, during, and after cyclones at a variety of intensities will be documented. The same analysis will be applied
to output from the high-resolution Regional Arctic System Model (RASM) and to output from
a suite of global climate models (GCMs). Using a novel set of metrics computed from the output of RASM, peak temporal and spatial scales of oceanic mixing, sea ice deformation, and turbulent fluxes associated with the passage of storms in the Arctic will be determined, in order to assess coupled cyclone-ocean-sea ice processes. Changes in the cyclone climatology between pairs of coupled RASM simulations, that differ only in sea ice and ocean state, and in current and end of the 21st century CMIP5 simulations will allow for assessment of cyclone response to changing ocean and ice state. This award is made by the Arctic Section of NSF Polar Programs and co-funded by the NSF GEO effort PREEVENTS.

北极气旋是造成海冰变形和海洋混合的重要因素。变更
在过去十年中，风暴活动和相关的大气反馈与北方高地季节性增加以及夏季海冰减少有关。气旋也可能对北极冰盖和海洋状况的变化做出反应，这表明#8232;大气-海洋-冰系统通过与气旋相关的过程紧密耦合。以前的北极模拟研究通常使用区域模型模拟，而没有完全耦合
或者完全耦合的全球气候模型，这些模型不允许与观测记录进行逐年比较。本研究将通过使用区域北极系统模型（RASM）来避免这种限制，该模型的输出直接对应于每月的观测记录。这&将允许评估冰-海洋-大气耦合过程的多个时间
和空间尺度，并将其与有限的北冰洋测量数据联系起来，以更全面地了解气旋活动的增加如何有助于将北极的表面气候转变为一个新的，更温暖的季节性海冰覆盖状态，以及气旋
将如何应对这种新的北冰洋状态。将通过与阿拉斯加气候评估和政策中心的伙伴关系，评估气旋对阿拉斯加北方和西部北极利益攸关方部门的影响，包括沿海社区和海洋运输，该项目的北极气旋及相关海洋和海冰状况清单将在国家冰雪数据中心存档。将在一个项目网页上提供北极气旋年度和季节性活动的历史时间序列、北极气旋的路径和强度图以及强气旋或有影响力气旋的个案研究。该项目将吸引研究生和一名博士后研究员参加，其成果将用于项目机构的大气和海洋科学本科和研究生课程。这项工作的成果将成为美国北极地区国家战略的优先事项，并将解决理解极端事件及其在北极气候系统中的作用的关键不确定性。最近北极海冰的减少增加了北极海洋-大气耦合的可能性，特别是在冰密集度低或冰边缘已经消退的地区。北极海洋-大气耦合增加的一个重要方面是海洋对风暴的反应可能增加。一旦被厚冰减轻，风引起的冰变形和海洋混合随着冰层变薄而增加。北极冰盖的减少和北冰洋的相关变暖也可能影响气旋的强度和频率。这笔赠款将支持在北极气旋存在的情况下调查大气-冰-海洋耦合的变化。它将促进我们对大气-海洋-冰的耦合过程的理解，重点是气旋在改变北极系统状态方面的作用和反应。一个气旋跟踪计划将应用于再分析，产生一个目录的北极气旋的位置，路径和强度，这将提供一个框架，分析冰和上层海洋对风暴的反应。冰浓度，海洋温度和盐度的响应，以及相关的冰质量平衡之前，期间和之后的气旋在各种强度将被记录。同样的分析将应用于高分辨率区域北极系统模型（RASM）的输出和一套全球气候模型（GCM）的输出。使用一套新的度量计算从RASM的输出，峰值海洋混合，海冰变形，湍流通量的时间和空间尺度与北极风暴的通道将被确定，以评估耦合的气旋海洋海冰过程。耦合RASM模拟之间的气旋气候学变化（仅在海冰和海洋状态方面有所不同）以及当前和21世纪末的CMIP 5模拟将允许评估气旋对海洋和冰状态变化的响应。该奖项由NSF极地计划的北极部分颁发，并由NSF GEO努力PREEVENTS共同资助。