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A parametric dynamical wave prediction model has been adapted and tested against semianalytic empirical results for steady conditions in a circular basin and extensive fid measurements of wave height, period, and direction. The adapted numerical model accurately predicts the directional spreading of waves for uniform steady wind that Donelan (1980) had predicted analytically for fetch-limited waves. When the model was applied to the central basin of Lake Erie and the results compared to observations of wave height and period (at two points in the lake) and direction (at one point), results for wave height and direction estimates were excellent compared to measurements at a research tower off the southern shore, but computed wave heights were lower than observed at a weather buoy in the western part. The • lodel somewhat underestimated wave periods at both places. Thus, with locally measured wind data as input, the model estimates wave height and direction well and wave period acceptably.Arbor, MI 48104.

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.

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