CMG: Collaborative Research on Multi-Scale Predictions of Arctic Ice

CMG：北极冰层多尺度预测合作研究

• 批准号: 0221926
• 负责人: Ronald Kwok
• 金额: $ 0.61万
• 依托单位: Jet Propulsion Laboratory
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0221926&HistoricalAwards=false
• 关键词: CMG; Collaborative; Research; Multi; Scale

Increasing our understanding of sea ice dynamics is vital because of the role sea ice plays in global atmospheric and ocean dynamics. In particular, the ability to better predict the opening of cracks in the ice, or leads, will improve our understanding of the Earth's weather, climate and ecology, as well as our ability to navigate Artic waters. Existing ice models have been of limited usefulness for forecasting the location and orientation of new leads and make no attempt to calculate the degree to which any given lead will open for predicted, or even observed forcing conditions. Even if effective models existed, until recently, there have been no data available for verification. We propose research that will exploit two significant developments and will ultimately allow accurate predictions of lead opening and orientation. First, motion of material points on large-scale regions of the Arctic ice cover have been recorded and are now available for complete winter seasons. Second, theoretical and numerical procedures have been recently developed for describing crack formation through the use of cohesive crack models. The proposed research is to develop a multi-scale, computational procedure to predict crack initiation, orientation, and width, in sea ice, under an observed set of loading conditions, and to verify the procedure using the newly available data. The successful completion of the research will set the stage for the next generation of models and numerical procedures in which realistic geophysical forces can be used to predict the detailed behavior of the Arctic ice cover.For the first time, large-scale motion data are available for points on the Artic ice cover. This unique dataset, produced by the Jet Propulsion Laboratory (JPL), is derived from high-resolution, spaceborn, Synthetic Aperature Radar (SAR) imagery, acquired by the RADARSAT satellite. These data are exactly what is needed to form a complete picture of ice deformation. A striking aspect of these images is linear features indicating the formation of leads, or openings in the sea ice. The ability to better predict the opening of leads will improve our understanding of the Earth's weather, climate and ecology, as well as our ability to navigate Artic waters. Existing ice models have been of limited usefulness for forecasting the location and orientation of new leads and make no attempt to calculate the degree to which any given lead will open for predicted, or even observed forcing conditions. Even if effective models existed, until recently, there have been no data available for verification. We propose to use the JPL data to develop and verify new material models for sea ice in order to predict crack initiation, orientation, and width. The successful completion of the research will set the stage for the next generation of models and numerical procedures in which realistic geophysical forces can be used to predict the detailed behavior of the Arctic ice cover. Moreover, sea ice is a central element in the Earth's climate system. An accurate ice model will benefit our ability to understand past climatic variability and to improve predictive capabilities through its inclusion in global ocean and climate models.

由于海冰在全球大气和海洋动力学中发挥的作用，增加我们对海冰动力学的了解至关重要。特别是，能够更好地预测冰层裂缝或铅的打开，将提高我们对地球天气、气候和生态的了解，以及我们在北极水域航行的能力。现有的冰模型对于预测新引线的位置和方向的用处有限，并且没有尝试计算任何给定的引线在预测的或甚至是观测到的强迫条件下的开放程度。即使存在有效的模型，直到最近，也没有可供验证的数据。我们提出的研究将利用两个重要的发展，并最终将使准确的预测导联开度和方向。首先，北极冰盖大范围区域上的物质点的运动已经被记录下来，现在可以用于整个冬季。其次，最近发展了通过使用内聚裂纹模型来描述裂纹形成的理论和数值方法。建议的研究是开发一个多尺度的计算程序，在一组观测到的载荷条件下，预测海冰中裂纹的萌生、取向和宽度，并使用新获得的数据来验证该程序。这项研究的成功完成将为下一代模型和数值程序奠定基础，在这些模型和数值程序中，可以使用现实的地球物理力来预测北极冰盖的详细行为。这是第一次可以获得北极冰盖上点的大规模运动数据。这一独特的数据集由喷气推进实验室(喷气推进实验室)制作，来自RADARSAT卫星获取的高分辨率星载合成孔径雷达(SAR)图像。这些数据正是形成一幅完整的冰变形图景所需要的。这些图像的一个引人注目的方面是线性特征，表明海冰中形成了铅或开口。能够更好地预测铅的开放将提高我们对地球天气、气候和生态的理解，以及我们在北极水域航行的能力。现有的冰模型对于预测新引线的位置和方向的用处有限，并且没有尝试计算任何给定的引线在预测的或甚至是观测到的强迫条件下的开放程度。即使存在有效的模型，直到最近，也没有可供验证的数据。我们建议使用喷气推进实验室的数据来开发和验证新的海冰材料模型，以预测裂纹的萌生、取向和宽度。这项研究的成功完成将为下一代模型和数值程序奠定基础，在这些模型和数值程序中，可以使用现实的地球物理力来预测北极冰盖的详细行为。此外，海冰是地球气候系统的中心要素。一个准确的冰模型将有助于我们理解过去的气候变化，并通过将其纳入全球海洋和气候模型来提高预测能力。