Understanding snow and sea ice properties at microwave frequencies for remote sensing applications during MOSAiC (MOSAiCmicrowaveRS)

在过去的几十年里，观察到了北极海冰状况的戏剧性变化。这些变化包括海冰范围、年龄和厚度的迅速下降，以及融化季节的延长。与此同时，北极的航运和近海活动的数量正在增加，需要改进海冰监测。被动和主动微波卫星遥感提供了多种海冰参数的反演，如海冰类型、厚度、漂移和范围。然而，这些参数的检索算法在某种程度上依赖于从有限的场景集获得的经验关系。它们大多缺乏降雪信息、入射角相关性和季节变化方面的信息。在全年马赛克探险的框架内，我们将借助具有很高时空变异性的现场和航空观测来改进其中一些反演算法。简而言之，这个项目包括以下几个方面：-今天，在微波频率下对海冰的卫星观测广泛可用，并用于业务应用和气候研究。-每天都可以从合成孔径雷达(SAR)、微波辐射计和散射计获得广泛的分辨率和频率。-在这里，我们将开发新的和改进的方法，从微波观测得出海冰的性质，特别是从合成孔径雷达得出的海冰类型和铅分布，以及从微波辐射计获得的雪性质和冰类型。-2019/2020年在北冰洋中部进行的为期一年的马赛克探险将提供必要的现场和空中观测。机载激光扫描仪，电磁冰层厚度探测和光学图像将能够评估完整季节周期的卫星结果。-现场微波雷达和辐射计测量与详细的雪和冰测量相结合，将有助于为雪和海冰遥感应用开发改进的辐射传输、发射和散射模型。

Over the past few decades dramatic changes in Arctic sea ice conditions have been observed. These changes include rapid declines in sea ice extent, age, and thickness coupled with extended melt seasons. In parallel the amount of shipping and offshore activities in the Arctic are increasing and demand for improved sea ice monitoring. Passive and active microwave satellite remote sensing offer retrieval of several sea ice parameters such as sea ice type, thickness, drift and extent. However, retrieval algorithms for these parameters are, to some degree, relying on empirical relationships obtained from a limited set of scenarios. They mostly lack snow information, incidence angle dependencies and seasonal variation aspects. In the framework of the year-round MOSAiC expedition we will improve some of these retrieval algorithms with the aid of in-situ and air-borne observations with high spatio-temporal variability. In short, this project covers the following aspects:– Satellite observations of sea ice at microwave frequencies are widely available today and are used both for operational applications and climate studies.– A wide range of resolutions and frequencies from Synthetic Aperture Radar (SAR), microwave radiometers and scatterometers are available on a daily basis.– Here we will develop new and improve current methods to derive sea ice properties from microwave observations, in particular ice type and lead distribution from SAR and snow properties and ice type from microwave radiometers.– The one-year long MOSAiC expedition in the central Arctic Ocean in 2019/2020 will provide necessary in-situ and airborne observations.– Airborne laser scanner, electromagnetic ice thickness sounding, and optical images will allow evaluation of satellite results for a complete seasonal cycle. – In-situ microwave radar and radiometer measurements in conjunction with detailed snow and ice measurements will aid the development of improved radiative transfer, emission, and scattering models for snow and sea ice remote sensing applications.