Multi-frequency microwave remote sensing of summer Arctic sea ice attributes as indicators of climate and biophysical processes

夏季北极海冰属性的多频微波遥感作为气候和生物物理过程的指标

• 批准号: RGPIN-2015-05540
• 负责人: Scharien, Randall
• 金额: $ 1.46万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=677230
• 关键词: Multi; frequency; microwave; remote; sensing

In the last 30 years, summer Arctic sea ice extent has rapidly declined, leading to uncertainties regarding the fate of the Arctic marine environment and the coordination of Arctic stakeholders. There is now an entirely new Arctic ice pack dominated by thinner first-year ice (FYI) instead of thicker multiyear ice (MYI). The areal fraction of low albedo melt ponds on summer ice, termed pond fraction (PF), has increased due to fewer topographical controls on flooding extent over FYI compared to rough MYI. Several field studies point to the coupling of PF evolution to rates of shortwave radiation absorption, light transmittance, upper ocean warming, under-ice primary production, and atmosphere-ocean biogeochemical exchanges, including contaminants. Our understanding of local scale PF evolution and relationships with components of the Arctic marine environment is not matched at regional and greater scales. By extension, parameterizations of PF in large scale sea ice models, largely based on local scale observations of MYI, are inadequate for reliable regional and basin-wide forecasts of sea ice and climate conditions. At all scales the impact of intra-seasonal melting state variations on PF evolution and coupled processes are poorly understood. A robust means by which to monitor and assess the seasonal decay of summer ice and related biophysical processes is needed. ******The proliferation of synthetic aperture radar (SAR) missions, including current and pending missions operating in constellation mode, will significantly enhance our ability to monitor the summer Arctic marine environment. Frequent, daily or better, regional scale observations regardless of cloud cover and weather conditions will contribute to monitoring and modeling studies within several interdisciplinary realms. This Discovery Grant will support a research program dedicated to the regional scale study of the summer Arctic ice-covered marine environment. Near term objectives will focus on understanding spatiotemporal characteristics of PF and ice melting state on FYI and MYI, their controlling mechanisms, and relationships to SAR imaging characteristics (frequency, polarization, and viewing angle). Research outcomes include the development of a robust, satellite earth observation based, framework for new and hind-cast studies of summer Arctic ice PF and melting state, as well as coupled biophysical processes. Contributions also include improvements to sea ice-climate model parameterizations, and enhancements to our ability to utilize SAR imagery from Canada's Radarsat-2 and pending Radarsat Constellation Mission to track and study sea ice during the fast changing summer melting period.***********

在过去的30年中，夏季北极海冰范围迅速下降，导致对北极海洋环境的命运和北极利益相关者的协调不确定。现在有一个全新的北极冰袋，以较薄的第一年冰（FYI）为主，而不是较厚的多年冰（Myi）。与粗糙的Myi相比，由于洪水量的洪水量较少，在FYI上的洪水范围内的地形控制较少，因此夏季冰的低反照率融化池塘的面积分数增加了。几项现场研究表明，PF进化与短波辐射吸收率，光透射率，上海上变暖，冰底冰的一级生产以及包括污染物在内的大气 - 海洋生物地球化学交换。我们对局部规模的PF进化以及与北极海洋环境组成部分的关系的理解与区域和更大的尺度不匹配。通过扩展，大规模海冰模型中PF的参数化，主要基于对Myi的局部规模观察，对可靠的区域和盆地范围内的海冰和气候条件的预测不足。在所有范围内，季节内熔化状态变化对PF进化和耦合过程的影响很少。需要一种强大的手段来监测和评估夏季冰和相关生物物理过程的季节性衰变。 ******合成孔径雷达（SAR）任务的扩散，包括在星座模式下运行的当前和未决任务，将大大增强我们监视夏季北极海洋环境的能力。无论云覆盖物和天气条件如何，频繁，每天或更好的区域尺度观察都将有助于在几个跨学科领域内监视和建模研究。这项发现赠款将支持一项研究计划，该计划致力于夏季北极冰覆盖的海洋环境的区域规模研究。近期目标将集中于了解FYI和MYI上PF和冰熔化状态的时空特征，它们的控制机制以及与SAR成像特征（频率，极化和视角）的关系。研究成果包括开发基于卫星的卫星地球观测，夏季北极冰PF的新框架和后期研究的框架以及融化状态以及耦合的生物物理过程。贡献还包括改进海冰气候模型参数，以及提高我们从加拿大Radarsat-2和待定Radarsat星座任务中使用SAR图像的能力，以在快速变化的夏季熔化期间跟踪和学习海冰。*****************************************************************************************************************************************************************************************************************************