南极冰盖底部环境特征冰雷达综合属性分析——以冰穹A区域为例

The bottom of the ice sheet is the concentrated area where the ice accumulates, the internal flow field changes, and the ice melts and re-freezes, the environmental characteristics of which become the most important and uncertain factors in the simulation and prediction of ice sheet evolution. Ice-Penetrating Radar is an important and effective technique to reveal the internal structure of ice sheet and has achieved great success over the past half-century. Travel-time and amplitude were the most effective sections of ice radar records, which can meet the requirements of the characterization on the thickness of ice sheet, the internal structure and the topography below the ice sheet, while it seems to be limited to image the complex bottom of the ice sheet. The study focus on the multi-attribute analysis based on the 2-D and 3-D radar data-sets, acquired from Zhongshan station → Dome A and Dome A respectively in Antarctic. Radar facies, by virtue of multi-attribute analysis, will be used to provide enhanced reliable quantitative information about the spatial distributions of complex ice layers, saturated sediments and bedrock with different roughness, and possible existed frozen-on ice, melt-water at the bottom of ice sheet, also combined with optimized multi-attribute profiles/maps, access to regional evolution and dynamic stabilization mechanism analysis for the ice sheet bottom.

冰盖底部是冰盖物质积累、流场变化、冰下融化和再冻结最集中的区域，受多重因素制约，该区域的环境特征成为模拟和预测冰盖演化过程最重要又最不确定的因素。冰雷达是揭示冰盖内部结构重要而有效的技术，在过去半个多世纪取得了巨大成功。传统雷达探测利用雷达波的旅行时和振幅进行分析解释，可以满足对冰盖厚度的测量、以及对冰盖内部构造和冰下地貌的成像，但对于冰盖底部复杂环境特征的研究，则仍有很大的局限性。本研究拟以南极中山站→冰穹A及冰穹A核心区域分别采集的二维及三维冰雷达数据体为对象，通过基于多属性特征的高精度雷达相分析，挖掘雷达记录中蕴藏的细节信息，识别研究区冰盖底部复杂结构的冰层、粗糙度不同的冰碛物和基岩，以及可能存在的复冻冰和融水，并借助全局最优决策的冰雷达多属性融合图，确定研究区冰盖底部环境特征的空间分布差异，分析其区域演化规律，探究冰盖动力稳定机制。

冰雷达是揭示冰盖内部结构重要而有效的技术，在过去半个多世纪取得了巨大成功。传统雷达探测利用雷达波的旅行时和振幅对目标体进行分析，可以满足对冰盖厚度的测量、以及对冰盖内部构造和冰下地貌的成像，但对于冰盖底部复杂环境特征的研究，则仍有很大的局限性，且单一频率天线采集的雷达数据有着一定的成像限制，高频天线提供浅部高分辨率信息，而低频天线拥有更深的穿透深度。为此，本研究以南极中山站→冰穹A及冰穹A核心区域采集的二维及三维冰雷达数据体为对象，通过冰雷达多属性分析，研究冰层内部及冰盖底部复杂特征，同时结合大量雷达实验数据，开展了多频雷达数据融合以及多属性特征融合研究，开发了基于遗传算法和基于滑动窗口的信号加权融合的多频雷达数据融合方法，以及基于二维离散小波变换的冰雷达多属性融合方法和定量化评价准则，研究结果可以获得更为准确、更为全面、更为可靠的冰雷达图像描述，明显改进了对冰层内部及冰盖底部环境特征的成像与定量化表征，也有助于进一步分析其区域演化规律，探究冰盖动力稳定机制。