  1.  NAME

  adcp_tide - Interpolate tide data to ADCP positions and time

  2.  USAGE

  adcp_tide

  3.  DESCRIPTION

  This Matlab script interpolates first all U and V tide components at
  ADCP positions for all times. These are then interpolated at ADCP
  ensemble times. The output file can be used to generate a vector plot
  of the tidal current at ADCP ensembles, and to detide ADCP currents.

  Tidal data are read from five different input files:

  1. Time in decimal days (suffix .t)

  2. Longitude in degrees (suffix .lon)

  3. Latitude in degrees (suffix .lat)

  4. Eastward tidal component (suffix .u)

  5. Northward tidal component (suffix .v)

  ADCP ensemble times can be read from the output of the getnav utility.
  See below for the input .

  4.  PARAMETERS

  The following parameters must be edited before running the script:

     year_base
        Year base corresponding to input decimal days

     tide_file
        Root name of ASCII files containing tide data. Extensions will
        be added automatically.

     adcp_file
        Name of a file with ADCP time,longitude and latitude as output
        by utility getnav.

     out_file
        Name of output file. See below for its .

  5.  INPUT FILE FORMAT

  Input data have only one column with one data for each grid point. The
  grid defines a two dimensional geographical area with associated
  longitude, latitude, eastward and northward currents values at each
  point. These data must be listed in the same order in each file. If
  several times are listed in the time file, current values must repeat
  themselves in the corresponding files in the same order as well. All
  of these files can be generated with the xtract(1) utility.

  6.  OUTPUT FILE FORMAT

  The generated file has the following columns:

  1. ADCP time

  2. Longitude

  3. Latitude

  4. Eastward tidal component

  5. Northward tidal component

  7.  SEE ALSO

  xtract(1)

  8.  AUTHORS

  Pierre Jaccard, Geophysical Institute, University of Bergen, 1999

