Scattering Strength Software
Version 1.0: 24 January 2003 (NRL 7144)

This folder contains 2 plotting routines and two folders,
SURFACE and BOTTOM INTERFACE, which in turn contain 
suites of Matlab routines designed to calculate the 
incoherent component of the bistatic scattering strength 
of the ocean
   - surface (air-sea interface + bubble clouds), &
   - bottom interface,
respectively (described below), as well as sample plots.
(The plotting routines apply to both software suites.)

N.B.: Besides being incoherent models, the algorithms assume
isotropic, pure-power-law roughness spectra.  So, while the 
routines are 3D, predictions for the forward scatter/specular 
direction should be not be regarded as being accurate. 
[We are currently testing Matlab code which will remove both 
these restrictions and will pass that along when available 
as Version 2.0. (Until this happens, we have set 0 dB as the
upper limit of interface scattering strengths.) Over the next year, 
we will also be adding a sediment-volume scattering model to 
complement bssint.m and, so, provide a full bottom scattering 
strength model.]

[Tested with Matlab Version 6, Release 12.]

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SURFACE SCATTERING STRENGTH: SSSRUN.m

Required computational functions:
 - sssnrl.m
 - sssint.m
 - sssbub.m
Required plotting function:
 - Either landscape.m or portrait.m

Functions sssnrl together with sssint and sssbub form a matlab 
implementation of (a more general version of) NRL's Semi-Empirical 
Surface Scattering Strength (SESSS) algorithm.

The functions sssint and sssbub return the component scattering 
strengths in dB from the sea surface interface (lowest-order small 
slope theory approximation) and bubble clouds, respectively. 
The function sssnrl returns the combined surface scattering 
strength in dB of the linear sum of these two components. 

The script file SSSRUN generates four example plots of surface 
scattering strength vs. various parameters (see sssplot.jpg).

The user can also select options (via ssopt) to output instead
either just the interface contribution (sssint, via ssopt = 1)
or just the bubble-cloud contribution (sssbub, via ssopt = 2).
[Note that for ssopt = 2, f should be <= 5000 Hz and that 
sssbub = 0 for U <= 3.] 

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BOTTOM-INTERFACE SCATTERING STRENGTH: BSSINTRUN.m

Required computational function:
 - bssint.m
Required plotting function:
 - Either landscape.m or portrait.m

Function bssint returns bottom-interface scattering strength in dB 
(lowest-order small slope theory approximation). 

The script file BSSINTRUN generates four example plots of bottom 
scattering strength vs. various parameters (see bssintplot.jpg).

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GENERAL REFERENCE:
R.C. Gauss, R.F. Gragg, R.W. Nero, D. Wurmser, and J.M. Fialkowski, 
“Broadband Models for Predicting Bistatic Bottom, Surface, and Volume 
Scattering Strengths,” NRL/FR/7100--02-10,042, Naval Research Laboratory,
Washington DC, September 30, 2002.
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