基于奇异谱分析的近海卫星测高波形重定方法及其应用研究

Satellite altimeter can collect abundant oceanic data which are widely applied in marine geodesy, geophysics and oceanography over open oceans. But the accuracy of satellite altimeter data is very low over coastal seas. Although the existing retracking algorithms can improve the coastal altimetry data quality to a certain extent, the retracked altimeter data over coastal seas cannot still satisfy the scientific and engineering requirement. One new waveform retracking method will be studied by analyzing the characteristics of coastal altimeter waveforms and the measurement modes of altimeter, and combining the reflection features of land/ seabed and sea surface with the singular spectrum analysis (SSA) and the multi-channel SSA (MSSA). The features of coastal altimeter waveforms will be analyzed by SSA/MSSA and then the temporal-spatial distribution of coastal altimeter waveform will be shown. One hybrid model of coastal waveform will be concluded by merging the Brown model and the Hayne model. Coastal altimeter waveforms will be searched and classified with SSA/MSSA based on satellite tracks of sea to land and land to sea and the observing modes. One new retracking method for coastal altimeter waveforms will be put forward by combining SSA/MSSA and the function fitting/statistical method. The temporal-spatial variations of coastal sea surface heights can be investigated by SSA/MSSA. The real altimeter data over coastal seas will be processed. The coastal sea level change and the coastal land vertical movement will be studied, and their prediction will be made by SSA/MSSA. One new retracking system of coastal altimeter waveforms will be developed and one coastal altimetry set will be formed by processing the real satellite altimetry data. The study will not only improve the altimetry data quality over coastal seas, but also broaden the altimetry applications over coastal areas. It is of significance for the applications and development of altimetry missions, especially for HY-2A, the first China altimetry satellite, and its following altimetry missions.

卫星测高采集了丰富的海洋信息，在深远海大地测量、地球物理和海洋学等领域获得了良好应用，但是近海测高数据质量严重下降。虽然现有波形重定方法在一定程度上改善了近海测高数据质量，但仍然无法满足有关需要。本项目主要研究：基于奇异谱分析的近海测高波形特征分析，研究近海测高回波时空规律，融合布朗模型和海恩模型，构建近海回波混合模型；根据测高卫星由海及陆和由陆及海不同轨迹、污染源以及测量模式，研究基于奇异谱分析的近海测高波形搜索和分类、集成奇异谱分析和函数拟合/统计法的近海测高波形重定算法，分析近海海面高的时空规律；对实际近海测高数据进行处理，研究近海海平面变化监测及近岸陆地沉降监测及其预测方法。通过研究，开发近海测高波形重定系统，构成近海测高数据集，不仅有效提高近海测高数据质量，而且拓宽卫星测高在近海的应用，对国际测高任务应用和发展，特别是我国的HY-2A以及后续测高任务具有重要意义。

卫星测高采集了丰富的海洋数据，在深远海大地测量、地球物理和海洋科学等领域获得了广泛应用，但是近海卫星测高数据质量严重下降，影响了测高近海应用。该项目开展了奇异谱分析（SSA）/多通道奇异谱分析（MSSA）的卫星测高波形消噪、建模仿真和波形重定算法研究，进行了波形仿真及测高误差分析，提出了基于波形导数的重定算法，有效改善测高数据质量。进行了星载DORIS、GNSS和SLR的测高卫星精密定轨（POD），提出了外符轨道检验方法，确保定轨精度和可靠性，减弱测高误差，进行我国HY-2A/2B/2C/2D星载GPS数据质量分析，验证了我国自主设计制造的星载GPS接收机的性能，实现了HY-2系列测高卫星厘米级精密定轨。研究了ka波段和ku波段测高计数据特征，特别是由海及陆和由陆及海的近海规律，基于验潮观测和GNSS数据分析了不同卫星测高数据精度，确定了多源测高数据定权策略。改善了多源卫星测高和相关海洋数据的融合处理策略，完善了多源数据的集成处理技术体系，对近30年的数据进行了实际处理，构建了1′×1′的全球海洋垂线偏差、重力异常和梯度、平均海面高和海底地形模型，首次构建了全球1′×1′海平面变化模型，提出了动态平均海面高模型构建方法，提出了基于验潮观测和GNSS数据的近海平均海面高模型改善方法。集成卫星测高、验潮观测和GNSS数据，确定了我国沿海陆地沉降速率。对我国HY-2系列测高数据进行了处理，首次在全球海洋平均海面高模型、海平面变化模型、海洋重力和垂线偏差模型构建中使用了HY-2AERM/GM数据，验证了我国测高卫星数据的精度和可靠性。该研究不仅有效改善了近海卫星测高数据质量，拓宽了卫星测高近海应用，而且构建有关海洋科学数据对于海洋大地测量、地球物理、海洋科技和空间科技等具有重要意义。