The aim of this work has been to study sea water models and complex water interactions with objects. These models have been used to evaluate the capabilities of calculating realistic Synthetic Aperture Radar (SAR) images and Radar Cross Section (RCS) signatures. The radar calculation method is based on ray tracing technique combined with physical optics. In the first chapter, sea surfaces models, based on statistical height distribution, are presented. The second chapter focuses on high frequency electromagnetic methods used for radar calculations. Numerical SAR images results of frozen scenes are shown in the third chapter. Very small details like small waves are visible. However, edge effects, created by the use of a discrete sea surface model, distort the results especially for the cross polarisation calculations. In addition, small water waves are responsible for a rapid radar signal decorrelation in animated sea surfaces and their simulation limits the size of the modeled sea surface. It has thus made it obvious that other methods have to be considered to take into account the noisy contribution of small water waves to the radar backscattered signal. Results of RCS calculations of sea surfaces with small waves are presented to evaluate this noise level. The following chapter describes two solutions to model interactions between water and objects. The proposed algorithms are based on convolution methods and pre-height maps. Finally the report includes a future research discussion on the possibility to use tiled models or to develop a fractal model decoupling large waves from small waves to improve calculations efficiency.