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searoughness

Surface height standard deviation for sea

    Description

    example

    hgtsd = searoughness(scale) returns the standard deviation of the surface height, hgtsd, for the specified sea state number as a scalar in meters.

    hgtsd = searoughness(scale,'ScaleType',scaletype) specifies the scale type.

    [hgtsd,beta0,windvelocity] = searoughness(___) returns additional outputs:

    • beta0 — Slope of the sea type in degrees. beta0 is 1.4 times the root mean square (RMS) surface slope. The surface σ0 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

    Examples

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    Obtain the surface height standard deviation in meters assuming a sea state of 2.

    hgtsd = searoughness(2)
    hgtsd = 0.1000
    

    Input Arguments

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    If you set scaletype to 'SeaState', scale is interpreted as the sea state, specified as a nonnegative scalar between [0,8]. If you set scaletype to 'WindScale', scale is interpreted as the Beaufort wind scale, specified as a positive scalar between [1,9].

    Dependency

    The interpretation of the scale argument depends on the value of scaletype name-value pair.

    Scale type, specified as either:

    • 'SeaState' — The function uses the Sea State model. When you specify this option, the scale input scale must be a nonnegative scalar between [0,8].

    • 'WindScale' — The function uses the Beaufort Wind Scale model. When you specify this option, the scale input scale must be a positive scalars between [1,9].

    Example: 'WindScale'

    Output Arguments

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    Standard deviation of the surface height, returned as a scalar. The model for height deviation, surface slope, and wind velocity is based on a model by Barton. Units are in meters.

    Slope of the sea type β0, in degrees, returned as a scalar.

    Wind velocity, returned as a scalar. The model for the height deviation, surface slope, and wind velocity is based on a model by Barton. Units are in meters per second.

    References

    [1] Barton, David K. Radar Equations for Modern Radar. Norwood, MA: Artech House, 2013.

    Extended Capabilities

    C/C++ Code Generation
    Generate C and C++ code using MATLAB® Coder™.

    Version History

    Introduced in R2021a