The correlation analysis of underwater topography SAR imaging and tidal current

Atidal current is one of the main factors of underwater topography SAR imaging, and the underwater topography SAR imaging is related to the tidal current because of its periodic variability.The SAR images of the same topography acquiring at different time are different.Taking the Taiwan Shoal as study area, five scenes of ERS-2 SAR images are acquired at different time, and the in situ measured water depth is used in the correlation analysis of the tidal current and the underwater topography SAR imaging.These five SAR images are evaluated firstly by the traditional image evaluation method to avoid the influence of SAR imaging factors them selves on the underwater topography SAR imaging.Then the tidal current field of the SAR imaging is determined by the tide and tidal current numerical simulation, and the wind direction is obtained by the QuikSCAT.Based on the above work, the correlation between a SAR backscattering coefficient and the in situ measured water depth is analyzed, and the relation between the underwater topography SAR imaging and the tide time is concluded.The result shows that the underwater topography SAR imaging has closely relation to the tidal current filed, and the SAR image of the underwater topography is best when the direction of the tidal current is close to the grads direction of the water depth.The backscattering coefficients of two SAR images of the same topography acquired on the condition of two opposite tidal current directions is opposing, i.e., the bright-dark stripes are reverse.Furthermore, fair wind or head wind related to the tidal current direction have no influence on the underwater topography SAR imaging.