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

利用现场和卫星多频偏振散射仪和 SAR 数据推导海冰积雪厚度信息

• 批准号: 238754-2011
• 负责人: Yackel, John
• 金额: $ 1.6万
• 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: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=547081
• 关键词: Derivation; snow; thickness; information; sea

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.

在过去的十年中，北极海冰最近迅速减少引起了科学界和媒体的广泛关注。这种减少既发生在季节范围上，也发生在厚度分布上。模型研究表明，由于人为产生的气体在大气中积聚导致温室效应增强，北极海冰的范围和厚度的长期下降趋势至少将持续几十年。参与最新政府间气候变化专门委员会第四次评估报告（IPCC-AR4）的全球气候模型显示，向夏季无冰北极的过渡可能会突然发生，而且比之前的预期更早。然而，由于整个北极在连续的时间和空间尺度上发生大规模的大气环流模式变化，海冰覆盖的范围和厚度分布每年仍然存在很大变化。一旦海冰形成，这些大气环流变化就会以积雪的形式沉积空间上不同量的降水，然而，由于云层覆盖和云层覆盖，我们使用基于光学的卫星遥感技术测量和量化这些降水量的能力受到严重限制。秋季和冬季的大部分时间都是 24 小时黑暗。海冰上的积雪是雪/海冰系统的关键组成部分，因为它控制着冰的厚度和冰的融化行为。因此，它也在很大程度上控制着冰的机械特性，例如冰的强度和破碎潜力。这项研究将使用从冰面和卫星获取的全天候成像微波遥感数据，以及积雪覆盖的热力学海冰和微波散射模型，这些模型由现场收集的雪和海冰特性数据提供。预期结果将允许估计春季过渡期间不同时间的积雪特征（厚度分布、雪水当量、液态水含量），以便更好地了解雪对海冰的作用，从而确定其作用北极海冰范围和厚度的年际变化。