Block VII: Surface Noise Parameters

This block contains the wavenumber sampling parameters for computing the noise covariance matrix. The parameters CMINS and CMAXS are the phase phase velocities defining the wavenumber integration interval. Note here that the continuous spectrum is always important for surface noise. Therefore CMAXS must be specified to a large number (e.g. 10⁸) to include the steep propagation angles. CMINS should be chosen small enough to include all important evanescent components.

Similar to OASN, the wavenumber sampling parameters NWSC, NWSD and NWSE are interpreted in two different ways by OASI, depending of the value specified for NWSD :

NWSD < 10

The wavenumber sampling parameters are given in the standard SAFARI format, with the parameters interpreted as follows:

NWSC

Total number of wavenumber samples, distributed equidistantly between and .

NWSD

Sampling point where the kernel computation starts. The kernel will be Hermite extrapolated. In this format NWSD will usually be set to 1 since the steep angles are always important.

NWSE

Sampling point where the kernel computation ends. The kernel will be Hermite extrapolated.

NOTE: The sampling parameters must be specified in this format for options K and C, which require equidistant sampling.

NWSD

The wavenumber sampling parameters are given individually for each of the three spectral regimes. This allows for a much denser sampling in the discrete spectrum without forcing a dense sampling of the smooth kernel in the other regimes.

NWSC

Number of wavenumber wavenumber samples distributed equidistantly over the continuous spectrum between and the critical wavenumber k_c corresponding to the compressional speed in the sub-bottom.

NWSD

Number of wavenumber wavenumber samples distributed equidistantly over the discrete spectrum between the critical wavenumber k_c corresponding to the compressional speed in the sub-bottom and the wavenumber k_w corresponding to the minimum sound speed in the water column.

NWSE

Number of wavenumber wavenumber samples distributed equidistantly over the evanescent spectrum between the wavenumber k_w corresponding to the minimum sound speed in the water column and .