PCC2HIST – Process Cubic Output to Lat/Lon

pcc2hist is used to post-process CCAM output from the cubic grid to the required output grid.  Usually the output is a regular latitude / longitude grid.  However, it is possible to output raw cubic grid (for combining parallel files) or TAPM grids.  A list of pcc2hist output variables can be found at the following link CCAM output variables.

 

pcc2hist is usually run with MPI according to

mpirun -np $nproc pcc2hist

where $nproc is the number of processes.  pcc2hist will automatically optimise the number of processes.  Typically the number of processes should be a factor of the number of input files.  8 input files per pcc2hist process is usually optimal.

 

Typical command line switches include

–cordex to format output for CORDEX

–interp=none to output cubic grid (for combining parallel files)

–interp=nearest to use nearest value interpolation

–interp=linear to use bi-linear interpolation

–interp=tapm to output on the TAPM grid

–vextrap=none to use end values for vertical extrapolation

–vextrap=linear to linearly extrapolate vertical values

–vextrap=missing to use missing values instead of extrapolation

-c $filename where $filename is the path to the namelist (default=cc.nml)

 

The pcc2hist namelist is divided into two parts

&input

ifile – Input filename (output from CCAM).  Do not include the “.000000” extension, but use the same name as the CCAM ofile.

ofile – Output filename

kta – Start time for reading data in mins (seconds for high-frequency output)

ktb – End time for reading data in mins (seconds for high-frequency output)

ktc – Time step for reading data in mins (seconds for high-frequency output).  Use -1 for all time-steps.

minlat – Minimum latitude of bounding box for regular output

maxlat – Maximum latitude of bounding box for regular output

minlon – Minimum longitude of bounding box for regular output

maxlon – Maximum longitude of bounding box for regular output

hres – Output resolution in degrees

use_plevs – Set to True for output on pressure levels

plevs – List of pressure levels for output in hPa.

use_meters – Set to True for output on meters above surface

mlevs – List of meter heights for output

dx – X grid spacing in meters for TAPM output

dy – Y grid spacing in meters for TAPM output

lx – Number of X grid points for TAPM output

ly – Number of Y grid points for TAPM output

save_ccam_parameters – Allows CCAM parameters to be saved in the history file when TRUE (default). 

&histnl

hnames – List of output variable names.  Use hnames=”all” for all output variables.

hfreq – Frequency of output data in minutes.  hfreq=0 is instantaneous output, hfreq=1440 is daily output.

htype – Type of output field.  Default is 4 byte floating point output.