 Usage: api2arl [-options]
  -h[help information with extended discussion]
  -e[encoding configuration file {name | create arldata.cfg}]
  -d[decoding configuration file {name | create api2arl.cfg}]
  -i[input grib data file name {DATA.GRIB2}]
  -o[output data file name {DATA.ARL}]
  -g[model grid name (4 char) default = {center ID}]
  -s[sigma compute=1 or read=2 or ignore=(0)]
  -t[top pressure (hPa) or level number for processing {20}]
  -z[zero fields (no=0 yes=1)initialization flag {1}]

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1) Create sigma.txt file by processing through all the levels
   and using the average pressure at each level and the surface
   to compute an equivalent sigma value for the packing
   configuration file. The sigma value is only needed for 
   many of the auxiliary programs, HYSPLIT will use the 3D
   pressure field instead of computing a value from the sigma.

   rm *.cfg
   api2arl -idata.grib2 -t41 -s1

2) Create arldata.cfg with sigma levels reads the sigma.txt file
   created in the previous step to write a new arldata.cfg file
   with the simga levels replacing the model level index number.

   rm *.cfg
   api2arl -idata.grib2 -t41 -s2

3) Edit arldata.cfg and api2arl.cfg to remove unwanted fields
   such as the 3D height field. PRES should always occur before
   THET so that HYSPLIT can convert THET to ambient. Also rename
   the default precipitation accumulation from TPP6 to TPP3.

   api2arl -idata.grib2 -t41 -a2 
