Radar Remote Sensing of Ocean Waves - Global Mapping of Mean and Peak Wave Parameters Extracted from SAR Cross Spectra

Abstract

Satellite remote sensing offers different methods for acquiring information on the open ocean and coastal regions. The synthetic aperture radar (SAR) is the only instrument capable of providing high-resolution 2D sea surface spectra on a global and continuous scale. Besides spectral sea state information, SAR image data (imagettes) of the sea surface offer plenty of additional information, especially about atmospheric effects. The aim of the present thesis is to investigate the performance of the ocean wave model WAM in comparison to marine parameters extracted from complex ERS-2 SAR data, as well as to investigate severe weather situations, e.g., hurricanes, with SAR imagettes and computed spectra. For this purpose, observed SAR cross spectra and modelled WAM ocean wave spectra are analysed. Typical sea state parameters like significant wave height and wavelength are retrieved from the spectra and evaluated. Tools generating global statistics and maps to analyse and present the information contained in the spectra are developed and applied to the collocated data sets. A new method to detect inconsistencies between observation and model is developed by forward mapping of modelled wave spectra into cross spectra for an independent comparison. Possible explanations for the deviations are discussed.