Oblique nonlinear interaction of internal solitary-like waves in the Andaman Sea

Oblique nonlinear interaction of two incident solitary waves, or soliton resonance, is important because it can produce a third solitary wave that has an amplitude up to 4 times the incident wave amplitude. Although this process is well studied for surface waves and in other fields of physics such as plasma, it has not been well studied for internal solitary-like waves (ISWs) in the ocean. In this study, we investigate oblique nonlinear interaction of ISWs in the Andaman Sea using three-dimensional MITgcm simulations. Our simulations demonstrate the occurrence of the oblique nonlinear interaction at several locations in the Andaman Sea. In the most prominent case, cylindrically spreading incident ISWs with less than 20 m amplitude produce an ISW of more than 70 m amplitude within ≈6 h. The modeled interaction is consistent with the Miles theory modified for incident waves with unequal amplitudes.