Avaliação da recuperação do espectro direcional de ondas a partir de dados de radar de abertura sintética (SAR)

• Autor(a) principal: Santos, Felipe Marques dos
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/11668
• topic: Mechanical Engineering; Ocean waves; Directional wave spectrum; Synthetic aperture radar; Hasselmann transformation; Sensibility; Engenharia Mecânica; Ondas oceânicas; Espectro direcional de ondas; Radar de abertura sintética; Transformação de Hasselmann; Sensibilidade; CNPQ::ENGENHARIAS::ENGENHARIA MECANICA

This work investigated the directional ocean wave spectra retrieval from SAR images using Hasselmann s inversion technique. The research was carried out on two fronts that were based on the adaptation of the inversion technique to process images of the recently launched satellites, Sentinel-1A & 1B, and the development of the Spectral Processor, a tool that generates a synthetic SAR image spectrum from a provided directional wave spectrum. The first one proposed the processing of two real SAR images obtained by Sentinel satellites using first-guess from the NOAA Wavewatch III numerical model and in situ control data from NDBC buoys. The second work front proposed and executed an extensive methodology for sensitivity analysis of the inversion technique, original and modified, in relation to the first-guess. In particular, the impacts of the variation of the main direction, wavelength and significant wave height of the first-guess on the recovered wave spectrum were evaluated using a robust SAR data processing and simulation system, which consists on the coupling of the Spectral Processor to the inversion technique. A total of 4908 experiments were performed and analysed according to the proposed evaluation criteria and indicators. The results indicated that the adaptation of the inversion technique for the use of Sentinel images was quite effective. Regarding the sensitivity analysis, it was verified that the modified inversion technique presented better results than those presented by its original formulation. It was possible to associate first-guess wave parameters variation ranges and generalized limits of wavelength and significant height values with satisfactory results. Finally, it was verified that the effects of the directional variation of the waves change according to the other wave parameters involved.