Multi-source Multi-temporal Sar Data Inversion Of Underwater Terrain In Phase Assimilation Model

Synthetic Aperture Radar (SAR) is one of the important microwave sensors and it is widely used in the field of ocean remote sensing. Underwater topography detection with SAR image is one of the important applications of SAR in the oceanic research. The final purpose of the research on the underwater topography detection with SAR image is to develop the operational detection technology of underwater topography with SAR image. The existing underwater topography detection with SAR image is based on the single SAR image and the detection result can't reflect the whole features of the underwater topography. So to develop an underwater topography detection method with SAR images acquired in the different times by the different satellites becomes the main work in this research field.Assimilation model and its algorithm of underwater topography detection with SAR images acquired in the different times by the different satellites was presented in this paper, which was based on the underwater topography SAR imaging mechanism and the representation of high frequency spectra of ocean waves presented by Yuan Yeli, and the feasibility of this model and algorithm was testified by the underwater topography of Taiwan Shoal detection with SAR images by this model. In this paper, the existing underwater topography detection technology with SAR image (underwater topography detection with the single SAR image) was used in the underwater topography of Taiwan Shoal detection, and the influences of initial water depth of the inversion calculation on the inversion results were studied. Furthermore, the imaging capabilities of SAR on the underwater topography in the Chinese coastal areas were analyzed.As for the application of the existing underwater topography detection technology with SAR image in the Taiwan Shoal, underwater topography of Taiwan Shoal was detected by seven scenes of SAR images, and the detection results showed that the same underwater topography detection results with the SAR images acquired in the different times can't reflect the whole features of the underwater topography.Concerning the study on the influence of the initial water depth of the inversion calculation on the inversion results, the results showed that the initial water depth should obtained by associating with some real water depth.With regard to the study on the assimilation model of underwater topography with SAR images acquired in the different times by the different satellites, the assimilation model and algorithm of underwater topography detection with SAR images acquired in the different times and by the different satellites were presented, and the underwater topography of Taiwan Shoal were detected by SAR images acquired in the different times by the different satellites of five different cases. The results show that this model and algorithm is feasible. The selection principle of SAR images used in the underwater topography detection with SAR images acquired in the different times by the different satellites was given.Finally, the SAR imaging capability of underwater topography in the Chinese coastal areas was analyzed under the analyses of the status of the tide and tidal current, the features of underwater topography and the information of underwater topography in the SAR images of the Chinese coastal areas. It is concluded that the areas where underwater topography can be detected by SAR in the Chinese coastal areas are Bohai Sea, the coastal areas of Subei, Taiwan Strait and the areas of the Nansha islands.