Study of Internal Solitary Waves Characteristics Using Synthetic Aperture Radar Imagery and the Korteweg-de Vries Numerical Model in the South Andaman Sea Alfiza N., Gaol M.G.L., Putri K.M.A., Mahendra S.A.H., Zhafran M.L. and Helmi M.
Departement of Oceanography, Faculty of Fisheries and Marine Science, Universitas Diponegoro, Indonesia
Departement of Marine Science, Faculty of Fisheries and Marine Science, Universitas Diponegoro, Indonesia
Abstract
Internal Solitary Waves (ISWs) are subsurface phenomena generated by the transformation of internal tides as they interact with complex seafloor topography, leading to intense vertical mixing and influencing subsurface transport processes. The South Andaman Sea, characterised by strong density stratification and intricate bathymetry, presents favourable conditions for ISW generation. This study aims to identify and characterise ISWs in this region using Sentinel-1 Synthetic Aperture Radar (SAR) imagery. Wave parameters were derived through the Korteweg-de Vries (KdV) model and validated with in situ oceanographic variables including temperature, salinity, and eastward and northward current velocities at propagation points. One dominant propagation point was identified, exhibiting a maximum wave amplitude of 558.92 m, a phase speed ranging from 3.29 to 6.54 m/s, horizontal current velocities up to 42.12 m/s, and vertical velocities reaching 10.32 m/s. The ISWs at this location displayed strong and coherent solitonic behaviour, supported by high kinetic and potential energy values and stable nonlinearity and dispersion parameters. The most energetic wave showed a kinetic-to-potential energy ratio of 539.77. These results underscore the utility of Sentinel-1 SAR imagery in detecting ISWs and demonstrate the value of integrating remote sensing with numerical oceanographic modelling to enhance our understanding of subsurface wave dynamics in tropical oceanic environments, particularly for risk mitigation and the enhancement of navigational safety, both at the surface and underwater, as well as for the security of offshore structures.
