The two measurement systems that have so far been directly used for wave measurements are the satellite Radar Altimeter (RA) and the Synthetic Aperture Radar (SAR). The RA is a vertically pointing pulsed radar designed to measure the range to the ocean surface with a few centimeters accuracy. The SAR produces images with very high resolution by tracking the phase and the amplitude of the return signal as the satellite moves, typically about 7–10 kilometers. I suggest you take a look at a paper by Krogstad and Barstow (1999) [ Satellite wave measurements for coastal engineering applications ]... I'm sure it will help you a lot with this concept.

would you allow me to make a not specialist guess?

the excitation power causes the harmonics born with frequency shifted, so the spatial harmonic wavelength(wave shape and pattern) shift should arise. Nonlinearities also cause modulational instability, which usually have some threshold. You know one of such called Tsunami. So If you know low-power conditions, an instability threshold, and maybe the pattern, you can guess the power, and probably the wave height. But the exact laws of the ocean dynamics are beyond my understanding. So I suppose, the radar is the right way.

Well, that is what SWAN does:

1) Wave propagation in time and space, shoaling, refraction due to current and depth, frequency shifting due to currents and non-stationary depth.

2) Wave generation by wind.

3) Three- and four-wave interactions.

4) Whitecapping, bottom friction and depth-induced breaking.

5) Dissipation due to aquatic vegetation, turbulent flow and viscous fluid mud.

6) Wave-induced set-up.

7) Propagation from laboratory up to global scales.

8) Transmission through and reflection (specular and diffuse) against obstacles.

9) Diffraction.

for speeding up, you can try cutting out everything below #3.