Derivation of snow thickness information on sea ice using in-situ and satellite based multi-frequency polarimetric scatterometer and SAR data

在过去十年中，北极海冰最近迅速减少的现象引起了科学界和媒体的极大关注。这种减少既表现在其季节性程度上，也表现在其厚度分布上。模拟研究表明，由于人为产生的气体在大气中积聚，造成温室效应增强，北极海冰的范围和厚度的长期下降趋势至少在今后几十年内将持续下去。参与最新政府间气候变化专门委员会第四次评估报告（IPCC-AR 4）的全球气候模型显示，北极向夏季无冰的过渡可能会突然发生，而且比以前预期的要早。然而，海冰覆盖的范围和厚度分布每年变化很大，这是因为大规模的大气环流模式变化在整个北极的时间和空间尺度上都是连续的。这些大气环流的变化表明，一旦海冰形成，就会以积雪的形式出现存款空间变化的降水量，但是，由于秋季和冬季大部分时间云层覆盖和24小时黑暗，我们使用光学卫星遥感技术测量和量化这些量的能力受到严重限制。海冰上的积雪是雪/海冰系统的重要组成部分，因为它控制着冰的厚度和融化行为。因此，它也在很大程度上控制了冰的机械性能，如冰的强度和破碎潜力。这项研究将使用从冰面和卫星沿着获得的全天候成像微波遥感数据，以及用现场收集的雪和海冰属性数据馈送的积雪覆盖的热力学海冰和微波散射模型。预期的结果将允许估计积雪的特点（厚度分布，雪水当量，液态水含量）在不同的时间在春季过渡，使更好地了解雪对海冰的作用，可以评估确定其在北极海冰的范围和厚度的年际变化的作用。

The recent and rapid reduction in Arctic sea ice has received considerable scientific and media attention during the past decade. This decrease has occurred to both its seasonal extent and to its thickness distribution. Modelling studies suggest that the long-term declining trend for both the extent and thickness of Arctic sea ice will continue for at least the next several decades due to an enhanced greenhouse effect resulting from the atmospheric build-up of anthropogenic produced gases. Global climate models participating in the latest Intergovernmental Panel on Climate Change - Fourth Assessment Report (IPCC-AR4) show that a transition to a summertime ice-free Arctic could occur both abruptly and earlier than previously anticipated. However, the sea ice cover remains highly variable from year-to-year within respect to its extent and thickness distribution owing to large scale atmospheric circulation pattern changes which operate over a continuum of time and space scales throughout the Arctic. These atmospheric circulation changes manifest to deposit spatially varying amounts of precipitation in the form of snow accumulation once the sea ice has formed, however, our ability to measure and quantify these amounts using optically based satellite remote sensing techniques is severely limited owing to cloud cover and 24-hour darkness during much of the fall and winter. The snow cover on sea ice is a critical component of snow/sea ice system because it controls the ice thickness and melt behaviour of the ice. As a result, it also largely controls the mechanical properties of the ice such as ice strength and break-up potential. This research will use all-weather imaging microwave remote sensing data acquired from both the ice surface and satellites along with snow covered thermodynamic sea ice and microwave scattering models fed with in situ collected snow and sea ice property data. The expected results will permit an estimation the snow cover characteristics (thickness distribution, snow water equivalent, liquid water content) at various times during the spring transition such that an improved understanding of the role of snow on sea ice can be assessed towards determining its role in the interannual variability in Arctic sea ice extent and thickness.