About using dual-polarization multi-frequency microwave observations for improved identification of thin ice and retrieval of its thickness

冬季，通过海冰覆盖(铅，冰层)开口的热交换可以比邻近厚冰上的热交换高出两个数量级。这样的开口是最大限度地产生冰的场所。总体而言，本研究旨在提高对薄冰的识别和分类，以及对其厚度的估计。将结合直升机在不同频率、极化和入射角度下对海冰雷达特征的测量以及同时进行的现场观测，分析现有和未来对海冰雷达特征的测量，这两项测量都是在对极地地区的实地战役中进行的。这项分析的一个方面将是改进薄冰雷达特征的数值模拟。本提案要求将第一个资助期再延长一年。在此扩展期间，我们将把薄冰识别和厚度反演算法应用于一个冰冻季节的卫星主动微波数据，我们将利用薄冰雷达后向散射数值模拟的结果并通过与独立数据的比较来评估和进一步优化算法，最后将得到的薄冰厚度分布与卫星被动微波测量结果进行解释和比较。

The heat exchange through openings in the sea-ice cover (leads, polynyas) can exceed the one over adjacent thick ice by two orders of magnitude during winter. Such openings are sites for maximum ice production. Overall, this study aims at improving the identification and classification of thin ice, and the estimation of its thickness. Available and future space-borne measurements of the radar signature of sea ice will be analyzed in combination with helicopter-borne measurements of the radar signature of sea ice at different frequencies, polarizations, and incidence angles, and concurrent in-situ observations, both carried out during field campaigns into the polar region. One aspect of this analysis will be the improvement of numerical modeling of the radar signature of thin ice. The present proposal asks for an extension of the first funding period by one additional year. During this extension we will apply the thin-ice identification and thickness retrieval algorithm to satellite active microwave data of one freezing season, we will evaluate and further optimize the algorithm by means of results from numerical modeling of the radar backscattering of thin ice and by comparison with independent data, and we will finally interpret and compare the obtained thin-ice thickness distribution with results obtained from satellite passive microwave measurements.