The FIELD program uses the modes calculated by KRAKEN and produces a shade file which contains a sequence of snapshots of the acoustic field as a function of range and depth. A snapshot is produced for every source depth specified by the user.
Files:
Name Unit Description
Input
*.FLP 5 FieLd Parameters
*.MOD 30-99 MODe files
Output
*.PRT 6 PRinT file
*.SHD 25 SHaDe file
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EXAMPLE AND DESCRIPTION OF FLP FILE:
/, ! TITLE
'RA' ! OPT 'X/R', 'C/A'
9999 ! M (number of modes to include)
1 0.0 ! NPROF RPROF(1:NPROF) (km)
501 200.0 220.0 / ! NR R(1:NR) (km)
1 500.0 / ! NSD SD(1:NSD) (m)
1 2500.0 / ! NRD RD(1:NRD) (m)
1 0.0 / ! NRR RR(1:NRR) (m)
(1) - TITLE
Syntax:
TITLE
Description:
TITLE: Title to be written to the shade file.
If you type a /, the title is taken from the
first mode file.
(2) - OPTIONS
Syntax:
OPTION
Description:
OPTION(1:1): Source type.
'R' point source
(cylindrical (R-Z) coordinates)
'X' line source
(cartesian (X-Z) coordinates)
OPTION(2:2): Selects coupled or adiabatic mode theory.
'C' Coupled mode theory.
'A' Adiabatic mode theory (default).
For a coupled mode run you ***must*** be sure that the
modes are finely sampled throughout the water column
so that FIELD can accurately
calculate the coupling integrals. This is done by using
a large number of receiver depths (NRD) when you
do the KRAKEN run. This number should be set to
give about 10 points/wavelength.
(3) - NUMBER OF MODES
Syntax:
M
Description:
M: Number of modes to use in the field computation.
If the number of modes specified exceeds the
number computed then the program uses all the
computed modes.
(4) - PROFILE RANGES
Syntax:
NPROF RPROF(1:NPROF)
Description:
NPROF: The number of profiles, i.e. ranges where a new
set of modes is to be used.
RPROF(): Ranges (km) of each of these profiles.
For a range independent problem there is only
one profile and its range is arbitrary.
mode files must exist for each range of a
new profile and be assigned in sequence to
units 30,31,... The modes for the last SSP
profile are extended in a range-independent
fashion to infinity so that RMAX can exceed
RPROF(NPROF).
*** NOTE: RPROF( 1 ) must be 0.0 ***
(6) - SOURCE/RECEIVER LOCATIONS
Syntax:
NR R(1:NR)
NSD SD(1:NSD)
NRD RD(1:NRD)
NRR RR(1:NRR)
Description:
NR: Number of receiver ranges.
(NR<4094 and NR*NRD <= 210000)
R(): The receiver ranges (km)
NSD: The number of source depths. (<51)
SD(): The source depths (m).
NRD: The number of receiver depths.
(<201 and NR*NRD < 210000)
RD(): The receiver depths (m).
NRR: The number of receiver range-displacements.
Must equal NRD. (YES, IT IS REDUNDANT)
RR(): The receiver displacements (m).
This vector should be all zeros for a perfectly
vertical array.
The field is computed by stepping through the
ranges, R(1:NR), and adding in the range
displacements, RR() before computing the field
on the array. Nonzero values are used to tilt or
distort the receiving array, thereby simulating the
distortion which occurs on an array deployed in
the ocean.
The format of the source/rcvr info is an integer
indicating the number of sources (receivers) followed by
real numbers indicating the depth (range) of each
receiver. Since this data is read in using list-directed
I/O you can type it just about any way you want, e.g. on
one line or split onto several lines. Also if your depths
are equally spaced then you can type just the first and
last depths followed by a '/' and the intermediate depths
will be generated automatically.