Changes in Sea Surface Slope Due to Internal Solitary Waves Revealed By Polarimetric SAR Images

The modulation of internal solitary waves (ISWs) produces complex and intriguing phenomena on the sea surface, such as changes in sea surface slope. Measuring this slope change using in situ observation is challenging. This manuscript employs SAR image inversion methods to describe it. The slope changes in the range and azimuthal directions are calculated based on the average scattering angle and polarization orientation angle, respectively. The mean square slope change of surface roughness is calculated in combination with the propagation direction of ISWs. The calculation results from L-band SAR images show that the sea surface slope at the regions where ISWs act is significantly lower than the surrounding water, reaching -45%, indicating that ISWs have a suppressive effect on sea surface slope change. This can be explained by the occurrence of quasi-specular reflection after ISWs modulate the sea surface under the SAR side-look detection structure.