mblevitus(1)

NAME
mblevitus - Create a water velocity profile which is representative of the mean annual water column for a specified 1 degree by 1 degree region.

VERSION
Version 5.0

SYNOPSIS
mblevitus [-Rlon/lat -Ooutfile -V -H]

DESCRIPTION
mblevitus generates a mean water sound velocity profile for a specified location using temperature and salinity data from the 1982 Climatological Atlas of the World Ocean [Levitus, 1982]. The water velocity profile is representative of the mean annual water column structure for a specified 1 degree by 1 degree region. The profile is output to a specified file which can be read and used by programs (e.g. mbbath or mbvelocitytool) which calculate swath sonar sonar bathymetry from travel times by raytracing through a water velocity model. The Levitus [1982] reference is:
     Levitus, S, Climatological Atlas of the World Ocean,
     NOAA Professional Paper 13, U.S. Government Printing Office,
     Washington D.C., 173pp, 1982.
The water sound velocity values are calculated using the DelGrosso equations, following:
     Dusha, B. D., P. F. Worcester, B. D. Cornuelle,
       B. M. Howe, "On equations for the speed of
       sound in seawater", J. Acoust. Soc. Am., 93,
       255-275, 1993
The implementation of these equations follows code written at the Ocean Data Facility of the Scripps Institution of Oceanography. The depth to which the Levitus database defines the water column reflects regional water depths which may be exceeded in places. mblevitus extends the water sound velocity profiles to a depth of 12000 meters using the deepest salinity and temperature values available in the database. If the specified location is subaerial, then no water velocity profile is calculated.

AUTHORSHIP
David W. Caress (caress@mbari.org)
  Monterey Bay Aquarium Research Institute
Dale N. Chayes (dale@ldeo.columbia.edu)
  Lamont-Doherty Earth Observatory

OPTIONS

-H  This "help" flag cause the program to print out a description of its operation and then exit immediately.

-O  outfile
    Sets the output file for the water velocity profile. Default: outfile = "velocity".

-R  lon/lat
    Sets the longitude and latitude of the location of the water velocity profile. Whole degrees should be used, as the database has a 1 degree by 1 degree resolution. Default: lon=0, lat=0.

-V  Normally, mblevitus outputs only a minor bit of information to the stdout stream. If the -V flag is given, then mblevitus works in a "verbose" mode and also outputs the program version being used and the complete water column structure used to calculate the water velocity profile.

EXAMPLES
Suppose that one wishes to obtain a mean annual water velocity profile for processing Hydrosweep DS bathymetry data collected on the Cocos-Nazca spreading center at 95W longitude and 2N latitude. The following will suffice:
     mblevitus -R-95/2 -Ovelocity_profile -V
The output will be:
 Program MBLEVITUS
 MB-system Version 4.5
 Location for mean annual water velocity profile:
   Requested: -95.0000 longitude 2.0000 latitude
   Used: 265.5000 longitude 2.5000 latitude
 Values defined directly by Levitus database: 27
 Values assuming deepest salinity and temperature: 19
 Velocity points written: 46
 Output file: velocity_profile
 Mean annual water column profile:
      Depth Temperature Salinity Velocity
     0.0000 25.6560 33.8830 1534.6998
    10.0000 25.4080 33.8230 1534.2112
    20.0000 24.5410 34.0190 1532.5010
    30.0000 23.3290 34.2400 1529.9032
    50.0000 19.7940 34.7450 1521.4298
    75.0000 15.9700 34.9210 1510.8373
   100.0000 14.5630 34.9400 1506.8495
   125.0000 13.9500 34.9320 1505.2728
   150.0000 13.5920 34.9270 1504.5077
   200.0000 13.0430 34.9100 1503.4935
   250.0000 12.4510 34.8780 1502.2893
   300.0000 11.4720 34.8190 1499.6840
   400.0000 9.4060 34.6990 1493.8119
   500.0000 8.0400 34.6390 1490.2903
   600.0000 7.0330 34.5950 1488.0126
   700.0000 6.2200 34.5740 1486.4380
   800.0000 5.5640 34.5620 1485.4464
   900.0000 5.0280 34.5620 1484.9211
  1000.0000 4.5840 34.5650 1484.7546
  1100.0000 4.1950 34.5730 1484.8076
  1200.0000 3.8570 34.5820 1485.0649
  1300.0000 3.5860 34.5970 1485.6061
  1400.0000 3.3320 34.6090 1486.2123
  1500.0000 3.1020 34.6140 1486.9097
  1750.0000 2.6290 34.6280 1489.0920
  2000.0000 2.3010 34.6440 1491.9139
  2500.0000 1.8770 34.6670 1498.6154
  3000.0000 0.0000 0.0000 1507.2345
  3500.0000 0.0000 0.0000 1515.9406
  4000.0000 0.0000 0.0000 1524.7273
  4500.0000 0.0000 0.0000 1533.5883
  5000.0000 0.0000 0.0000 1542.5173
  5500.0000 0.0000 0.0000 1551.5078
  6000.0000 0.0000 0.0000 1560.5533
  6500.0000 0.0000 0.0000 1569.6471
  7000.0000 0.0000 0.0000 1578.7823
  7500.0000 0.0000 0.0000 1587.9523
  8000.0000 0.0000 0.0000 1597.1499
  8500.0000 0.0000 0.0000 1606.3682
  9000.0000 0.0000 0.0000 1615.6001
  9500.0000 0.0000 0.0000 1624.8383
 10000.0000 0.0000 0.0000 1634.0754
 10500.0000 0.0000 0.0000 1643.3042
 11000.0000 0.0000 0.0000 1652.5171
 11500.0000 0.0000 0.0000 1661.7062
 12000.0000 0.0000 0.0000 1670.8641 The contents of the output file velocity_profile are:
 # Water velocity profile created by program MBLEVITUS
 # MB-system Version 4.5
 # Run by user <caress> on cpu <menard> at <Wed Mar 26 15:43:53 1997>
 # Water velocity profile derived from Levitus
 # temperature and salinity database. This profile
 # represents the annual average water velocity
 # structure for a 1 degree X 1 degree area centered
 # at 265.5000 longitude and 2.5000 latitude.
 # This water velocity profile is in the form
 # of discrete (depth, velocity) points where
 # the depth is in meters and the velocity in
 # meters/second.
 # The first 27 velocity values are defined using the
 # salinity and temperature values available in the
 # Levitus database; the remaining 19 velocity values are
 # calculated using the deepest temperature
 # and salinity value available.
 0.000000 1534.699829
 10.000000 1534.211182
 20.000000 1532.500977
 30.000000 1529.903198
 50.000000 1521.429810
 75.000000 1510.837280
 100.000000 1506.849487
 125.000000 1505.272827
 150.000000 1504.507690
 200.000000 1503.493530
 250.000000 1502.289307
 300.000000 1499.683960
 400.000000 1493.811890
 500.000000 1490.290283
 600.000000 1488.012573
 700.000000 1486.437988
 800.000000 1485.446411
 900.000000 1484.921143
 1000.000000 1484.754639
 1100.000000 1484.807617
 1200.000000 1485.064941
 1300.000000 1485.606079
 1400.000000 1486.212280
 1500.000000 1486.909668
 1750.000000 1489.092041
 2000.000000 1491.913940
 2500.000000 1498.615356
 3000.000000 1507.234497
 3500.000000 1515.940552
 4000.000000 1524.727295
 4500.000000 1533.588257
 5000.000000 1542.517334
 5500.000000 1551.507812
 6000.000000 1560.553345
 6500.000000 1569.647095
 7000.000000 1578.782349
 7500.000000 1587.952271
 8000.000000 1597.149902
 8500.000000 1606.368164
 9000.000000 1615.600098
 9500.000000 1624.838257
 10000.000000 1634.075439
 10500.000000 1643.304199
 11000.000000 1652.517090
 11500.000000 1661.706177
 12000.000000 1670.864136

SEE ALSO
mbsystem(l), mbvelocitytool(l), mbprocess(l), mbset(l), mbm_xbt(l)

BUGS
None known.