Derivation of snow thickness information on sea ice using in-situ and satellite based multi-frequency polarimetric synthetic aperture radar data

在过去10多年里，北冰洋海冰面积的下降受到了相当大的关注。海冰约占地球表面积的11%，是全球辐射和能量平衡以及决定地球对气候变化反应的关键变量。海冰上的积雪是一个重要的物理变量，它在海-海-冰-大气界面的质量和能量交换中起着核心作用。由于雪的高反照率，在春季过渡季节，短波辐射交换在海冰-反照率反馈机制中占主导地位。春季融化的开始和最终在海冰表面形成液态水融化池塘导致海冰表面反照率的迅速下降，从而导致冰川融化速度的增加。北极海冰的春季融化在空间和时间上都是高度可变的，在很大程度上受大气变暖之前海冰上积雪厚度的时间和大小的控制。关于海冰上的雪的信息很少。这是因为在远距离测量雪的分布方面存在固有的困难和/或北极高地气候和降水报告站缺乏代表性。关于积雪厚度分布及其与海冰类型的关系的历史数据也很少。来自观测和模拟研究的证据表明，海冰上的雪在表面和体积内可见光和微波能量的相互作用中发挥着中心作用。我的研究解决了一些关键问题，以了解在春季融化过渡期，结合地面和卫星遥感数据，积雪覆盖的海冰的可见光和微波电磁相互作用之间的相互关系。每年将从寒冷环境实验室环境和与其他气候和海冰测量相一致的北极高地现场环境中收集积雪厚度的观测值，以及地面和卫星遥感数据，目的是量化雪在各种空间和时间尺度上显示海冰范围和厚度方面所起的作用。

Considerable attention has focused on the satellite measured decline of sea ice extent in the Arctic Ocean over the past 10+ years. Sea ice makes up approximately 11% of the Earth's surface area and is a critical variable in the global radiation and energy balances and to determining the Earth's response to climate change. The snow cover on sea ice is an important physical variable that plays a central role in mass and energy exchange across the ocean-sea ice-atmosphere interface. Because of the high albedo of snow, the shortwave radiative exchange dominates the sea ice-albedo feedback mechanism during the spring transition season. The onset of spring melt and the eventual formation of liquid water melt ponds on the surface of the sea ice cause rapid decreases in the surface albedo, and as such, cause an increase in the rate of ice melt. Spring melt on Arctic sea ice is highly variable in both space and time and is largely governed by the timing and magnitude of snow thickness on the sea ice prior to sufficient atmospheric warming. Information of snow on sea ice is scarce. This is because of the inherent difficulties in measuring snow distributions remotely and/or the lack of representativeness of High Arctic climate and precipitation reporting stations. Historical data on snow thickness distributions and their relationship to types of sea ice are also rare. Evidence from both observational and modeling studies indicate that snow on sea ice plays a central role in the interaction of visible and microwave energy at the surface and within the volume. My research addresses a number of key questions to understand the inter-relationship between the visible and microwave EM interactions of snow covered sea ice using a combination of surface and satellite based remote sensing data during the spring melt transition period. Observations of snow thickness will be collected annually from both a cold environment laboratory setting and in-situ High Arctic environments coincident with other climate and sea ice measurements along with surface and satellite based remote sensing data for the purpose of quantifying the role snow plays in manifesting sea ice extent and thickness at a variety of spatial and temporal scales.