README -- Describes contents of ExtData/CHEM_INPUTS/ann_mean_trop_200202
06 Mar 2015
GEOS-Chem Support Team
geos-chem-support@g.harvard.edu


Overview:
===============================================================================

Contains annual mean tropopause files for GCAP and GEOS-4 meteorology.
These were created from the bpch files in the prior ann_mean_trop_200202
directory paths.

NOTE: These will allow us to phase out bpch input completely.  These data
are required for backwards compatibility with GEOS-4 and GCAP GEOS-Chem
simulations.


Files:
===============================================================================

ann_mean_trop.gcap.4x5.nc   : Annual mean tropopause, GCAP   4 x 5   grid
ann_mean_trop.geos4.2x25.nc : Annual mean tropopause, GEOS-4 4 x 5   grid
ann_mean_trop.geos4.4x5.nc  : Annual mean tropopause, GESO-4 2 x 2.5 grid


How the files were created:
===============================================================================

Bob Yantosca ran GAMAP routine bpch2coards on the existing files, e.g.

   IDL> bpch2coards, 'ann_mean_trop.gcap.4x5',   'ann_mean_trop.gcap.4x5.nc'
   IDL> bpch2coards, 'ann_mean_trop.geos4.2x25', 'ann_mean_trop.geos4.2x25.nc'
   IDL> bpch2coards, 'ann_mean_trop.geos4.4x5',  'ann_mean_trop.geos4.4x5.nc'

and then wrote the following script to o call NCO commands in order to adjust
the file and variable attributes for better COARDS compliance:

   #!/bin/tcsh
   
   ncrename -v TR_PAUSE__TP_LEVEL,TP_LEVEL $1
   
   ncatted -a gamap_category,TP_LEVEL,o,c,"TR-PAUSE" $1

   ncatted -a missing_value,TP_LEVEL,o,f,1e15 $1

   ncatted -a _FillValue,TP_LEVEL,o,f,1e15 $1

   ncatted -a add_offset,TP_LEVEL,o,f,0 $1

   ncatted -a scale_factor,TP_LEVEL,o,f,1 $1
   
   ncatted -a History,global,o,c,"Tue Mar  3 12:18:38 EST 2015" $1
    
    ncatted -a Contact,global,o,c,"GEOS-Chem Support Team (geos-chem-support@g.harvard.edu)" $1
   
   ncatted -a References,global,o,c,"www.geos-chem.org; wiki.geos-chem.org" $1
   
   ncatted -a Title,global,o,c,"Annual mean tropopause data for GEOS-4" $1 
   
   exit(0)

The script then run from the Unix command line as follows:

   fixatts.csh ann_mean_trop.gcap.4x5.nc'
   fixatts.csh ann_mean_trop.geos4.2x25.nc'
   fixatts.csh ann_mean_trop.geos4.4x5.nc'
   

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README -- Contents of ann_mean_trop/
Bob Yantosca
bmy@io.harvard.edu
20 Feb 2004


Files:
------
ann_mean_trop.geos1.4x5  : Annual mean tropopause heights and flux flags
ann_mean_trop.geos3.4x5  :  for GEOS-1, GEOS-3, GEOS-STRAT and GEOS-4 grids
ann_mean_trop.geoss.4x5  :  at 4 x 5 horizontal resolution.
ann_mean_trop.geos4.4x5  : 
			   
Files are in binary punch format.


Source:
-------

For GEOS-1, GEOS-STRAT, and GEOS-3:
===================================
To create the "ann_mean_trop.geos*.4x5" files, you need to first run the
GEOS-CHEM code for a full year (or for as long as you have met fields on
disk, if less than one year), and save out the ND55 diagnostic to the binary
punch file. 

Then you can use the IDL code

	~bmy/IDL/regrid/create_amt.pro

which will create the "ann_mean_trop.geos*.4x5" files.  Tracer 1 in this file
is the annual mean tropopause height in levels, and tracer 2 is the flux
diagnostic flags (which determine if the Strat/Trop exchange is coming from
the top, left, right, or a combination of these).


For GEOS_4:
===========
The GEOS-4 annual mean tropopause were computed as follows:
  
(a) Bob Yantosca downloaded the *mis_x* HDF-EOS files from GMAO's machine 
    mintz.gsfc.nasa.gov for each day of 2003.  These files contain the 
    TROPP (tropopause pressure in hPa0 met field. 

(b) Routine ~bmy/IDL/regrid/create_geos4_tropp.pro was used to read
    the HDF-EOS files and save them to BPCH format.  

(c) Routine ~bmy/IDL/regrid/create_geos4_amt.pro was used to create
    an annual mean tropopause based on the surface pressure and
    tropopause pressure for the year 2003.  This should be OK for
    other years as well...it's an average.


Notes:
------
(1) The "ann_mean_trop.geos*.4x5" files are read into GEOS_CHEM by routine
    "read_tropopause.f".