The inversion of remote sensing signatures of internal solitary waves (ISWs) can retrieve dynamic characteristics in the ocean interior. However, the presence of ubiquitous large‐amplitude ISWs poses challenges to the commonly used weakly nonlinear methods for parameter retrieval. Through laboratory experiments, we establish a relationship between surface features and internal characteristics of ISWs by the remote sensing imaging mechanism. The results demonstrate that strong nonlinearity significantly influences the retrieval of ISWs, primarily manifested in the calculation of wave‐induced velocities and the applicability of ISW solutions. A fully nonlinear model Dubreil–Jacotin–Long equation is used in the retrieval and has been tested under different conditions. Mooring observations indicate that the determination of ISW parameters from satellite images is affected by the complexity of in situ stratification, but additional remote sensing information such as surface velocities enables us to perform retrievals even if the real‐time measurement of pycnocline depth is not available.

The remote sensing inversion of internal solitary waves (ISWs) enables the retrieval of ISW parameters and facilitates the analysis of their spatial variability. In this study, we utilize continuous optical imagery from the FY-4B satellite to extract real-time ISW propagation speeds throughout their evolution from generation to shoaling. ISW parameters are retrieved in the northern South China Sea based on the quantitative relationship between sea surface current divergence and ISW surface features in optical imagery. The inversion method employs a fully nonlinear equation with continuous stratification to account for the strongly nonlinear nature of ISWs and uses the propagation speed extracted from continuous imagery as a constraint to determine a unique solution. The results show that as ISWs propagate from deep to shallow waters in the northern South China Sea, their statistically averaged amplitude initially increases and then decreases, while their propagation speed continuously decreases with decreasing depth. The inversion results are consistent with previous in situ observations. Furthermore, a three-day consecutive remote sensing tracking analysis of the same ISW revealed that the spatial variation in its parameters aligned well with the abovementioned statistical results. The findings provide an effective inversion approach and supporting datasets for extensive ISW monitoring.

Earth's rotation imposes a dynamical barrier on the free propagation of internal tides at high latitudes, raising questions about the fate of tidal energy poleward of the critical latitude. Satellite observations reveal spiral internal solitary waves (ISWs) along the continental slope of the South Orkney Plateau. Although these waves might be attributed to direct steepening of low‐frequency internal tides, theoretical estimates of their propagation speed are nearly twice those inferred from observations. Using high‐resolution simulations, we resolve this inconsistency by identifying a topographically steered energy cascade: subinertial diurnal internal tides, initially trapped by the slope, undergo nonlinear evolution that generates superinertial harmonics. This frequency upshift allows tidal energy to surpass rotational constraints, radiate offshore, and ultimately evolve into the spiral ISWs. These results identify a distinct energy cascade pathway for internal wave dynamics in polar oceans and demonstrate how tidal energy can be redistributed despite rotational limitations.