Characterization of HFSWR Ocean-Ionospheric Response With Joint Gravity Wave Features Based on Dual-Coupled Duffing Oscillator

This letter describes the inaugural identification of ocean-ionosphere echoes in high-frequency surface wave radar (HFSWR) that manifest joint gravity wave characteristics, influenced by typhoons. Furthermore, it proposes a phase transition criterion for HFSWR based on the Duffing system, referred to as HPTC, accompanied by its quantitative standards, aiming to clarify the complex interplay between the ocean and the ionosphere during typhoon episodes. Data from the HFSWR ocean-ionosphere, characterized by joint gravity waves during Typhoon Muifa, was employed as input signals to stimulate the Duffing system. This facilitated the observation of the Duffing system's response characteristics and the exploration of HFSWR ocean-ionosphere echo characteristics under intense maritime events. The foundation of HPTC rests on the dual-coupled Duffing oscillator, conceived from a high-dimensional chaotic viewpoint. Experimental results corroborate the newly introduced phase transition criterion delineated in this letter, underscoring its efficacy in unveiling the inherent attributes of the HFSWR ocean-ionosphere. Conclusively, the discovery of joint gravity wave characteristics in the HFSWR ocean-ionosphere echoes stimulated by typhoons, together with the introduction of HPTC, offers an innovative approach and a robust technical foundation for the focused study of the HFSWR ocean-ionosphere amid intense marine activities.