The limited wavelength and the rapidly changing conditions due to short fetches and complex coastal shapes in enclosed seas pose a big challenge to the applications of satellite SAR data. In order improve the understanding of some aspects of image formation in such conditions, the authors are pursuing a long term work mainly based on numerical implementation of satellite SAR two-wavelength models of the sea surface. Numerical sea surface instantaneous height and velocity realizations are produced from given spectral shapes and the images are synthesized by taking into account the local surface tilt and orbital velocity. Different hypotheses are tested for the local scattering function, such Valenzuela's-like shapes. The work presented here is aimed in particular at clarifying the treatment of Doppler-induced effects such as velocity bunching; its role in identifying spectral characteristics is shown by making use of simple monochromatic wave fields and by taking into account the influence of resolution on the image formation. An example is also given of image spectral analysis in the vicinity of a wave measuring buoy in the Mediterranean.