An integrated hydrodynamic-electromagnetic model which combines a full-spectrum numerical solution of the wave action equation with a two-scale composite radar backscatter model is described, and results are presented for several internal wave cases observed during recent synthetic aperture radar experiments. The combined model predicts radar backscatter modulations significantly larger than those predicted by a simple Bragg scattering model under relatively high wind speeds (> 5 m/s), particularly at short wavelengths (X band) and for horizontal polarization. Furthermore, these predictions are in general agreement with observations in some cases where the simple Bragg model fails, Under other conditions, particularly at lower wind speeds and for vertical polarization, the predictions of the composite model are not significantly different from those of the Bragg model. In some of these cases, both models appear to underpredict the observed radar modulations, indicating that additional hydrodynamic and/or electromagnetic effects are present which are not included in either model. ¿ American Geophysical Union 1988