Identifiability of Kelvin Wakes in SAR Imageries: The Role of Time-Varying Characteristics and Decoherence Effect of Wake

The Kelvin wake, a distinctive ship-generated wave pattern in synthetic aperture radar (SAR) imagery, plays a vital role in advancing ocean observation theory. Current simulations rely on approximations that neglect critical physical mechanisms: time-varying characteristics and decoherence effects, sensitivity to the integration time, relative angle between ship heading and radar azimuth, and different sea conditions. To overcome resulting simulation-reality discrepancies, we propose KWFull-Link SARSim—a full-link model integrating ocean surface motion, time-varying scattering, and decoherence effects. Analyses demonstrate that L-band SAR suffers certain wake visibility degradation due to time-varying characteristics, especially in air-borne scenarios, while wake contrast exhibits marked dependence on ship-SAR azimuth alignment. Further, ocean cut-off wavelengths significantly influence signatures. Validation against ten real SAR images (TerraSAR-X, Sentinel-1A, ALOS PALSAR) confirms model efficacy: pronounced time-varying characteristics and decoherence effect in ALOS L-band explain wake erasure, while azimuth misalignment in Sentinel-1A C-band causes unilateral visibility loss. We establish that faithful Kelvin wake simulation must explicitly incorporate (i) platform-dependent time-varying characteristics and (ii) azimuth-modulated decoherence effects, overcoming critical limitations of traditional methods.