ASA 127th Meeting M.I.T. 1994 June 6-10

2pUW1. The two-scale model from the point of view of a small slope approximation.

A. G. Voronovich

NOAA/ERL/Environmental Technol. Lab. R/E/WP1, 325 Broadway, Boulder, CO 80303

The two-scale model (TSM) is widely used for interpretation of data concerning wave scattering at rough surfaces. On the other hand, a small slope approximation theory (SSA) is able to consider the same situation without introducing somewhat arbitrary scale-dividing parameter. It is shown that under appropriate conditions the SSA reproduces the results of TSM. Dividing of spectrum of roughness into two components can be considered in this case as a numerical mode for calculating the corresponding integrals arising in SSA. Moreover, statistical dependence of the small-scale component of roughness upon shape of large-scale undulating surface is taken into account. Thus the statistics of small-scale component of roughness is not assumed to be space homogeneous. As a result the small-scale component of spectrum in the final expression for scattering cross section is modified. The forms of correlation functions of roughness which should be substituted to the presented theory are specified. Corresponding results can be of interest for scattering of high-frequency waves from surfaces possessing wide spectrum of roughness (as wavy sea surface). [This work is partly supported by NRC.]