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

一年海冰上的积雪是海洋冰冻圈的一个关键组成部分，因为它的热导率相对较小，控制着冰的增加和消融速率。在春夏过渡期间，雪的作用是使海冰与变暖的大气隔绝，最终调节冬季海冰的厚度和夏季海冰的融化行为，并在很大程度上决定其机械强度，最终控制海冰的夏季破裂潜力。例如，如果海冰在冬季生长，而积雪很薄，那么冰的厚度就会最小化。这样一来，这种薄积雪更有可能在春季提前融化，从而使融水淹没冰面，降低反射率并吸收更多的太阳辐射，导致海冰提前消融。******我的总体研究计划目标是：1)提高我们对FYI上积雪时空厚度分布的理解，2)提高我们对与这些分布相关的物理和电学性质的理解，以及3)利用基于地面传感器开发的算法，利用星载有源微波传感器对FYI上的积雪厚度进行高级估计。*******科学方法使用：1)地面和空间微波遥感系统的多频率和极化能力，2)一套独特的同步现场测量雪的地球物理和电学性质数据，来自北极野外站和3)计算机/数学模型的雪覆盖海冰的物理和电学过程。这些都被用于开发反演算法来估计雪厚分布。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）两个地点获得各种类型的雪特性。后一个地点将包括对我们测量来自活跃微波的污染物（包括石油）的能力的受控实验室研究。由CFI创新基金资助的丘吉尔海洋观测站的海冰中观油（OSIM）和环境观测系统将为本研究项目提供世界一流的基础设施。*******通过开发、测试和验证从现场收集的数据和通过这些微波系统对FYI的雪厚估计，我希望这项研究能够提供关于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，以更好地了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产出和结果产生的增强信息，这些信息可以直接告知气候科学家和政策制定者有关我们北极水域海上航行（包括邮轮旅游和洲际航运）的预期增长。******

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).******