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

第一年(FYI)海冰上的积雪是海洋冰冻圈的关键组成部分，因为由于其相对较小的导热系数，它控制着冰的积累和消融速度。在春夏过渡期间，雪起到隔离海冰与大气变暖的作用，最终调节冬季海冰厚度和夏季融化行为，并在很大程度上决定其机械强度，最终控制海冰夏季解体潜力。例如，如果海冰在冬季生长，积雪较薄，则冰层厚度将被最小化。因此，这种薄薄的积雪更有可能在春天更早地融化，从而使融化的水淹没冰面，降低反射率，吸收更多的太阳辐射，导致更早的海冰消融。 我的主要研究计划目标是：1)提高我们对FYI上积雪的时空厚度分布的了解；2)提高我们对与这些分布相关的物理和电学特性的了解；3)利用星载有源微波传感器，通过使用地面传感器开发的算法，对FYI上的积雪厚度进行更高层次的估计。 科学方法使用：1)地面和星载微波遥感系统的多频率和极化能力，2)北极实地站提供的一套独特的现场测量的雪的地球物理和电学性质数据，以及3)积雪覆盖的海冰物理和电过程的计算机/数学模拟。这些都被用来开发反演算法来估计FYI上的积雪厚度分布。每年将在北极(2017-2022年，Nu-chars的剑桥湾)和亚北极(2018-2028年的丘吉尔海洋观测站)获取各种类型FYI的雪属性。后一个地点将包括关于我们测量活跃微波中的污染物(包括石油)的能力的受控实验室研究。CFI创新资助的丘吉尔海洋观测站的海洋中石油冰系(OSIM)和环境观测系统(我是该观测站的联合PI)将为开展这一研究计划提供世界级的基础设施。 通过从现场和通过这些微波系统收集的数据开发、测试和验证FYI上的积雪厚度估计，我希望这项研究将提供关于FYI积雪的关键信息，这些信息可以被纳入海冰、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。通过研究成果和成果，加拿大将受益于该项目产生的更多信息，这些成果可以直接向气候科学家和政策制定者通报我国北极水域(邮轮旅游和洲际航运)海洋航行预期增加的情况。

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).