Climate forcing of physical and electrical properties of snow covered sea ice

积雪海冰物理和电特性的气候强迫

• 批准号: RGPIN-2017-04888
• 负责人: Yackel, John
• 金额: $ 1.97万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711283
• 关键词: Climate; forcing; physical; electrical; properties

The snow cover on first-year (FYI) sea ice is a critical component of the marine cryosphere because it controls ice accretion and ablation rates due to its relatively small thermal conductivity. The snow acts to insulate the sea ice from the warming atmosphere during the spring to summer transition and ultimately regulates winter sea ice thickness and summer melt behavior, and largely determines its mechanical strength which ultimately controls sea ice summer break-up potential.. For example, if the sea ice grows in winter with a thin snow cover, the ice thickness will be minimized. This thin snow cover is then more likely to melt earlier in spring, thereby flooding the ice surface with melt water, lowering the reflectivity and absorbing more solar radiation, leading to earlier sea ice ablation. My overarching research program objectives are to: 1) Improve our understanding of the spatial and temporal thickness distribution of snow on FYI, 2) Improve our understanding of the physical and electrical properties associated with these distributions and 3) Upscale estimates of snow thickness on FYI with spaceborne active microwave sensors from algorithms developed using surface-based sensors. The scientific approach uses: 1) the multi-frequency and polarimetric capabilities of both surface and space-borne microwave remote sensing systems, 2) a unique suite of coincident in-situ measured snow geophysical and electrical property data from Arctic field stations and 3) computer/mathematical modelling of snow covered sea ice physical and electrical processes. These are employed in concert to develop inversion algorithms to estimate snow thickness distributions on FYI. Snow properties from various types of FYI will be obtained annually at both Arctic (Cambridge Bay, NU - CHARS, during 2017-2022) and sub-Arctic (Churchill Marine Observatory from 2018-2028) locations. The latter location will include controlled laboratory studies on our ability to measure contaminants, including oil, from active microwaves. An Oil in Sea Ice Mesocosm (OSIM) and Environmental Observing system at the CFI Innovation funded Churchill Marine Observatory on which I serve as co-PI will provide world class infrastructure to undertake this research program. By developing, testing and validating snow thickness estimates on FYI from data collected in situ and via these microwave systems, I expect this research to provide critical information on FYI snow cover which can be incorporated within sea ice, microwave scattering and climate models towards better understanding the near and long-term fate of Arctic sea ice. Canada will benefit from the enhanced information generated from this project through the research outputs and results which can directly inform climate scientists and policy makers regarding the expected increase in marine navigation of our Arctic waters (both cruise tourism and intercontinental shipping).

第一年（仅供参考）海冰上的积雪是海洋冰冻圈的重要组成部分，因为它的导热系数相对较小，因此控制着冰的增生和消融率。在春季到夏季的过渡期间，雪的作用是将海冰与变暖的大气隔离，并最终调节冬季海冰的厚度和夏季的融化行为，并在很大程度上决定其机械强度，从而最终控制海冰夏季的破裂潜力。 ，如果海冰在冬季生长，积雪很薄，冰的厚度就会最小化。这种薄薄的积雪更有可能在春季提前融化，从而使冰面被融水淹没，降低反射率并吸收更多的太阳辐射，导致海冰更早消融。 我的总体研究计划目标是：1) 提高我们对 FYI 上雪的空间和时间厚度分布的理解，2) 提高我们对与这些分布相关的物理和电气特性的理解，以及 3) 对 FYI 上雪厚度的高级估计星载有源微波传感器采用基于表面传感器开发的算法。 该科学方法使用：1）地面和星载微波遥感系统的多频和偏振能力，2）来自北极现场站的一套独特的一致现场测量的雪地球物理和电特性数据，以及3）积雪覆盖的海冰物理和电过程的计算机/数学建模。这些被共同用来开发反演算法来估计仅供参考的积雪厚度分布。每年将在北极（2017-2022 年期间，剑桥湾，NU - CHARS）和亚北极（2018-2028 年期间丘吉尔海洋观测站）地点获得各种类型的雪属性。后一个地点将包括受控实验室研究，研究我们通过主动微波测量污染物（包括石油）的能力。由 CFI Innovation 资助的丘吉尔海洋观测站的海冰中宇宙油 (OSIM) 和环境观测系统（我担任联合负责人）将为开展这项研究项目提供世界一流的基础设施。 通过根据现场收集的数据和通过这些微波系统开发、测试和验证 FYI 积雪厚度估计，我希望这项研究能够提供有关 FYI 积雪的关键信息，这些信息可以纳入海冰、微波散射和气候模型中，以便更好地理解北极海冰的近期和长期命运。加拿大将受益于该项目通过研究成果和成果产生的增强信息，这些成果和成果可以直接向气候科学家和政策制定者通报北极水域海上航行（游轮旅游和洲际航运）的预期增长。