Study on the amplitude inversion of internal waves at Wenchang area of the South China Sea

The field experiment is conducted from April 16, 2005 to July 20, 2005 at Wenchang area east of Hainan Island (19°35'N, 112°E) of China. Internal wave packets are observed frequently with thermistor chains during the experiment. Meanwhile, internal waves are also detected from a synthetic aperture radar (SAR) image on June 19, 2005 and several other moderate-resolution imaging spectroradiometer (MODIS) images near a mooring position. The distance between the positive and negative peaks induced by the internal wave can be obtained from satellite images. Combined with remote sensing images and in situ data, a new method to inverse the amplitude of the internal wave is proposed based on a corrected nonlinear Schrödinger (NLS) equation. Two relationships are given between the peak-to-peak distance and the characteristic wavelength of the internal wave for different nonlinear and dispersion coefficients. Based on the satellite images, the amplitude inversion of the internal waves are carried out with the NLS equation as well as the KdV equation. The calculated amplitudes of the NLS equation are close to the observation amplitude which promise the NLS equation a reliable method.