基于海冰像元结构分析的辽东湾浮冰厚度反演研究

The sea ice in Liaodong Bay is the most severe ice condition in China, so the thickness inversion of the floating ice in Liaodong Bay is the effective measures on ice condition monitoring and disaster prevention. But little work on the sea ice pixel structure and the obtains of the field observation data become the restrictions for the thickness inversion. Taking the floating ice as the study object, this project comes up with the scientific research methods on the construction of ice thickness inversion and the analysis of the pixel of sea ice. The main research as follows: A method of changing point to area is built based on the NOAA/AVHRR data; The distribution of floating ice in Liaodong Bay based on the analysis of sea ice pixel structure; To formulate the ice thickness inversion model based on the theory of solar shortwave radiation and the subarea parameterization; Then the dynamic distribution, regional differentiation and the pixel thickness defining methods of the floating ice in Liaodong Bay will be studied;From the above, this research comes up with a remote sensing thickness inversion method of floating ice in the Liaodong Bay based on the analysis of sea ice pixel structure(considering the visible spectrum only); The error analysis will be made by the field observation of icebreakers and etc.

辽东湾是我国冬季冰情最为严重的海区，浮冰厚度反演是冰情监测和防灾减灾的有效手段。然而，海冰像元内部结构不清晰、实测浮冰数据匮乏，成为制约辽东湾浮冰厚度反演的主要瓶颈。本项目以辽东湾浮冰厚度为研究对象，对浮冰厚度遥感反演模型构建原理和海冰像元结构分析方法进行基础科学研究。具体研究内容包括：海冰遥感数据（NOAA/AVHRR）由"点"及"面"的转化方法；基于海冰像元结构分析的辽东湾浮冰分布规律研究；建立基于太阳短波辐射吸收理论的辽东湾浮冰厚度反演模型，结合浮冰分布规律进行模型分区参数化研究；在海上平台和岸基雷达监测基础上，研究海冰像元结构的动态分布、区域分异与像元冰厚界定方法；在上述研究的基础上，建立基于海冰像元结构分析的辽东湾浮冰厚度反演方法（不考虑云覆盖条件下引入SAR等观测方法，仅研究可见光条件下的冰厚反演）,并利用破冰船等采集手段获取的实测数据对应用该方法的反演结果进行误差分析与订正。

辽东湾浮冰厚度反演是冰情监测和防灾减灾的重要手段。本项目构建了基于高光谱的浮冰厚度遥感反演模型，并进行了海冰厚度反演估算；以岸基雷达监测数据为基础，开展了冰型提取研究和现场验证，获取了尼罗冰的雷达提取参数；依据海冰光学辐射传输过程，充分利用海冰在不同波段的吸收和散射特性（光谱维信息），提出了一个以MODIS数据为基础的适用于一年生海冰厚度估算的海冰厚度实用化模型。该模型用MODIS第1波段估算海冰厚度，用MODIS第2波段和第5波段反射率做差分得到每个像元的海冰差分衰减指数（Difference Attenuation Index，DAI），用DAI估算像元级别的MODIS第1波段的海冰综合衰减系数，并将该模型应用于MODIS数据估算渤海海冰厚度，并用实际海冰调查数据予以验证。. 本项目从遥感冰厚反演的基本原理出发，以像元结构分析的角度推导出了适用于辽东湾浮冰的实用化冰厚反演模型，解决了冰厚反演仅仅依靠统计数据和经验判断的问题，为大范围的冰厚遥感反演和海冰灾害风险评估提供了技术支撑，具有重要的理论意义和实践意义。