WAVE-CURRENT AND WAVE-TOPOGRAPHIC INTERACTIONS USING SEASAT SYNTHETIC APERTURE RADAR OBSERVATIONS AND ANALYTICAL OCEAN MODELS (SEASAT SAR, WAVE-CURRENT INTERACTION, REMOTE SENSING, WAVE MOTION, WAVE-TOPOGRAPHIC INTERACTION)

This dissertation investigates the capability of SEASAT synthetic aperture radar (SAR) to detect wave-current and wave-topographic interactions in the Gulf Stream area by analyzing the refracted wave directions obtained from different methods. Four study methods have been employed: the optical Fourier transform (OFT), the fast Fourier transform (FFT), the kinematical, and the dynamical methods. The first two methods were applied to analyze the SAR data for estimating the dominant wave directions. The last two methods were applied to calculate the refracted wave directions for comparison with those measured by the OFT and FFT analyses. General theories of wave-current and wave-topographic interactions were formulated by assuming the ocean waves to be linear and steady-state. The SAR data from Rev. 0974 on September 3, 1978 over the Gulf Stream off Cape Hatteras, N.C. were utilized. Some 49 study positions located within this study area were chosen for this investigation. Results showed that the refracted wave directions obtained from the analyses of SAR data, from both the OFT and FFT methods, were in reasonable agreement with those obtained from kinematical and dynamical methods, with arithmetical means ranging from -0.2(DEGREES) to 6.9(DEGREES). The bending tendency of the surface gravity wave rays constructed from the four methods was also in agreement. Intensities of SAR wave spectra at dominant wavelengths were highly correlated both with average waveheights and with squares of average waveheights, with the correlation coefficients of 0.79 and 0.80, respectively. The FFT technique does offer surface wave dynamic information in great detail and the SAR wave spectra do provide high quantitative potential for the detailed observation of surface gravity waves.