As the wave height increases, the imaging process enters a regime in which 
the smearing effects due to random surface motions become important. Over 
a limited wavenumber interval, these effects combine with velocity bunching 
effects to produce a nearly flat transfer function, so that the SAR image 
spectrum more closely approximates the wave height spectrum. Finally, as 
the wave height increases further, smearing and nonlinear mapping effects 
cause large distortions in the image spectrum. Within the first two 
regimes, it would seem possible to infer the wave height spectrum in a 
wavenumber region near the spectral peak from the SAR image spectrum, us ing 
a relatively simple conversion factor. In the third regime, the relation- 
ship between the wave height and image spectra is less straightforward, and 
information in important regions of the spectrum may be lost in the noise. 
Acknowledgments 
  
This work was supported by NASA Headquarters under Contract No. 
N00014-81-C-0692. 
References 
Alpers, W.R., D.B. Ross, and C.L. Rufenach, On the Detectability of Ocean 
Surface Waves by Real and Synthetic Aperture Radar, J. Geophys. Res., Vol. 
86, 6481-6498, 1981. 
  
Alpers, W., Monte Carlo Simulations for Studying the Relationship Between 
Ocean Wave and Synthetic Aperture Radar Image Spectra, J. Geophys. Res. 
88, 1745-1759, 1983. 
  
Beal, R.C., D.G. Tilley, and F.M. Monaldo, Large- and Small-Scale Spatial 
Evolution of Digitally Processed Ocean Wave Spectra from SEASAT Synthetic 
Aperture Radar, J. Geophys. Res., 88,'1761, 1983. 
  
Hasselmann, K., R.K. Raney, W.J. Plant, W. Alpers, R.A. Shuchman, D.R. 
Lyzenga, C.L. Rufenach, and M.J. Tucker, Theory of SAR Ocean Wave Imaging: 
A MARSEN View, J. Geophys. Res., 90, 4659-4686, 1985. 
  
Hasselmann, D.E., M. Dunckel and J.A. Ewing, Directional Wave Spectra 
Observed During JONSWAP 1973, J. Phys. Oceanogr., 10, 1264-1280, 1980. 
  
Pierson, W.J., and L. Moskowitz, A Proposed Spectral Form for Fully 
Developed Wind Seas Based on the Similarity Theory of S.A. Kitaigorodskii, 
J. Geophys. Res., 69, 5181-5190, 1964. 
  
Plant, W.J., W.C. Keller, and A. Cross, Parametric Dependence of Ocean 
Wave-Radar Modulation Transfer Functions, J. Goephys. Res., 88, 9747-9756, 
1983. 1 
  
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