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Reflectivity of sea clutter

returns the normalized radar cross section (`nrcs`

= seareflectivity(`scale`

,`graz`

,`freq`

)`nrcs`

) in meters squared for
the specified sea scale `scale`

, at the grazing angle
`graz`

, with the transmitted frequency
`freq`

.

specifies the polarization of the transmitted wave.`nrcs`

= seareflectivity(`scale`

,`graz`

,`freq`

,'Polarization',`pol`

)

specifies the scale type.`nrcs`

= seareflectivity(`scale`

,`graz`

,`freq`

,'ScaleType',`scaletype`

)

`[`

returns additional outputs:`nrcs`

,`hgtsd`

,`beta0`

,`windvelocity`

] = seareflectivity(___)

`hgtsd`

— Standard deviation of the surface height for the specified sea state number as a scalar in meters`beta0`

— slope of the sea type in degrees.`beta0`

is 1.4 times the root mean square (RMS) surface slope. The surface σ^{0}value for sea clutter reflectivity is computed based on the NRL Sea Clutter Model by Gregers-Hansen and Mittal`windvelocity`

— wind velocity in meters per second.

The sea reflectivity model is valid given the following conditions:

Frequencies from 0.5 - 35 GHz

Sea States from 0 - 6 (Wind Scale from 1 - 7)

Grazing angles from 0.1 - 60 degrees

The model does not include variation with azimuth or wind direction. The NRL empirical model matches experimental results with an absolute deviation of about 2.2 to 2.3 dB for grazing angles from 0.1 to 10 degrees. A deviation of 2.6 dB can be seen for grazing angles above 10 degrees and below 60 degrees. The model for the height deviation, surface slope, and wind velocity is based on a model by Barton.

`searoughness`

| `landroughness`

| `landreflectivity`

| `clutterSurfaceRCS`