Research On Airborne Wave Spectrometer Wave Spectrum Inversion

Waves are small-scaled wind-generation gravity waves on the sea surface. Wave spectrum, the significant statistic property of waves, is an effective way for wave research and plays an important role in wave theories research, wave forecast and marine engineering. Nowadays, the main instrument for wave spectra measurement in large area is Synthetic Aperture Radar (SAR). However, the distorting and azimuthal focusing during SAR imaging have greatly reduced the precision of wave spectra inversion.Wave spectrometer, the special radar for wave spectra measurement, is most useful for wave spectra operational monitoring with the advantages of simple modulation function, immediate inversion and high precision. The wave spectrometers today are mainly airborne. The thesis carried out research on wave spectra inversion on the basis of airborne wave spectrometer experiment in Bohai Sea, offering technical support for the operational space borne wave spectrometer. The main work includes research on wave spectra inversion using airborne wave spectrometer data and the results comparison and influence factors analysis.On wave spectra inversion using airborne wave spectrometer data, modifications were made to the data process method proposed by foreign researchers according to the pulse technic adopted in the experiment. The method of data preprocess was determined, and the transformation formula between frequency spectrum and wave number spectrum was given when the waves in Bohai Sea are regarded as shallow-water wave. And the spectra discrepancies in different azimuth and along the flight orientation were presented, indicating the necessity of wave spectra average in azimuth and along the flight direction. Then wave spectra were averaged and wave parameters such as significant wave height (SWH) were calculated.On the results comparison and influence factors analysis, the significant wave heights(SWH) inversed from the airborne wave spectrometer data were qualitatively compared with SWH of Jason-1 and Jason-2 altimeters. According to the comparison, analysis were made on the possible factors influencing wave spectra inversion, such as data calibration, platform altitudes and modulation spectra correction, providing reference for wave spectra inversion improvement.