Purpose:     computes one day of atmospheric loading and the corresponding
             Centre-of-gravity motion (CMC), or extracts local air pressure

This script is called by  aploading ,  run_extract_airp   and other programs in
/home/hgs/Oload/smhi

Air pressure fields to input: {path}{year}/m_month/dday
You may use smhi-apf2bin.out (hgs/Oload/p/m/smhi-apf2bin.f)
to prepare these fields from the ftp copy.

The command must be issued from a directory that contains
the auxiliary files sitefile.stacov and topo.flg

Options:

-i          - Generates instruction input, to be piped to an *.ins file,
              e.g. that.ins. To execute, issue olfg that.ins and enter a
              Dollar sign at the instruction file prompter.

-test       - Verbose and request confirmation before exec.

-o results  - Specify a string to prepend filename,
              default results = apl, see below.
-o and -ts    are mutually exclusive.

-lc [file]  - Local collection (loading field values at sites) output file.
              Default file name {results}local.collection
-nl         - Under -lc: No load computation.

-tf file    - topo flag file for input.

-ts         - Output to time series files, one per site, append mode.
              Format is #n date:hh radial east north, units = metre.
-ts path    - To prepend generated file names (SITE_apl.tsf) by path string.

-nzr        - Produce a near-zone report, a file named
              nzr_${year}${month}${day}.asc
              in the directory declared by -ts

-nocmc      - Don't produce Centre-of-Mass corrections.
-cmc file   - Write Centre-of-Mass corrections to this file.
              Default is -cmc {path}/geoc_ib.tsf
              where path is from -ts option.

-p path     - Default = "gap" (global air pressure), for pressure
              fields input

-s sitefile - Specify a stacov file. For devising a default, run_olfg contains
                  set fs=itrf_96jan09.stacov
-S sitefile - Specify a site file that explains itself to get_sites (ols06.f).

year month day - specify year as e.g. 1993,
                        month as e.g. jan
                        day as e.g. 19

-ts style output is recommended (but is not the default).
The alternative is "collected" output, i.e. output collects all
all sites to two files per run,
        {results}{year}{month}{day}.v   (vertical, units = mm)
and     {results}{year}{month}{day}.h   (horizontal = North and East)
unless the -o option is used. In that case, no date is included in the
file name; just .v and .h are added; instead, the file is opened in
append mode.
To override append mode, specify -N. Default results = apl

By default, CMC is computed and output goes to default file name
{path}/geoc_ib.tsf