README -- Describes contents of ExtData directory tree
01 Mar 2018
GEOS-Chem Support Team
geos-chem-support@g.harvard.edu


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

The ExtData directory tree is the root-level data directory for GEOS-Chem.
All GEOS-Chem data is accessible via subdirectories of ExtData (some of which
are symbolic links to other directories).

CHEM_INPUTS/           : Non-emissions data for GEOS-Chem chemistry modules

GCAP_4x5@              : Links to data on the GCAP 4x5 data pat

GEOS_0.25x0.3125/      : Data on the GEOS 0.25 x 0.3125 global grid

GEOS_0.25x0.3125_CH/   : Data on the GEOS 0.25 x 0.3125 CH grid
                         - Includes GEOS-FP met and bpch data

GEOS_0.25x0.3125_NA/   : Data on the GEOS 0.25 x 0.3125 NA grid
                         - Includes GEOS-FP met and bpch data

GEOS_0.5x0.625_AS/     : Data on the GEOS 0.5 x 0.625 AS grid
                         - Includes MERRA-2 met

GEOS_0.5x0.625_NA/     : Data on the GEOS 0.5 x 0.625 NA grid
                         - Includes MERRA-2 met

GEOS_2x2.5/            : Data on the GEOS 2 x 2.5 grid
                         - Includes GEOS-FP/MERRA-2 met and bpch data

GEOS_4x5/              : Data on the GEOS 4 x 5 grid
                         - Includes GEOS-FP/MERRA-2 met and bpch data

GEOS_c360/             : Data on the C360 cubed-sphere grid
                         - Includes GEOS-FP met 

GEOS_NATIVE/           : Native resolution bpch emissions data

GEOS_MEAN/             : Data from past 1-year benchmark runs

HEMCO/                 : Data for use with the HEMCO emissions component

NOTES: 
- These are the data directories as represented at Harvard.  If disk
  server stores other types of data (e.g. GEOS_0.25x0.3125_EU), then you can
  put those directories here.

- Bpch data are considered obsolete in GEOS-Chem v10-01 and later as they
  are now superceded by netCDF data read in by HEMCO. We keep select bpch
  data here for use with the GEOS-Chem adjoint and GEOS-Chem v9-02 (the last
  pre-HEMCO version of GEOS-Chem). At some point in the future, support for bpch
  format will be removed completely from GEOS-Chem and these files may be
  removed.


Setting directories in input.geos
===============================================================================

Please add the following settings in the SIMULATION MENU section of your
input.geos file:

   Root data directory     : /n/holylfs/EXTERNAL_REPOS/GEOS-CHEM/gcgrid/data/ExtData
    => GEOS-FP subdir      : GEOS_FP/YYYY/MM/
    => MERRA-2 subdir      : MERRA2/YYYY/MM/
   Dir w/ 1x1 emissions etc: /n/holylfs/EXTERNAL_REPOS/GEOS-CHEM/gcgrid/data/ExtData/GEOS_NATIVE/


The "Root data directory" should be set to ExtData (wherever that is on your
system).  

The "Dir with 1x1 emissions etc" is left as-is for backwards compatibility
with older code.  This code will be eventually removed from GEOS-Chem as
more specialty simulations are made compatible with the HEMCO emissions
component.

GEOS-Chem will prefix the proper resolution-specific directory to the GEOS-FP
or MERRA-2 subdirectories.  For example, if you compile GEOS-Chem with

   make GRID=4x5 ...etc...

then you should see the following output in the log file:

   SIMULATION MENU
   ---------------
   Start time of run           : 20130701 000000
   End time of run             : 20130801 000000
   Run directory               : ./
   Data Directory              : /n/holylfs/EXTERNAL_REPOS/GEOS-CHEM/gcgrid/data/ExtData/
   CHEM_INPUTS directory       : /n/holylfs/EXTERNAL_REPOS/GEOS-CHEM/gcgrid/data/ExtData/CHEM_INPUTS/
   Resolution-specific dir     : GEOS_4x5/
   GEOS-FP    sub-directory    : GEOS_4x5/GEOS_FP/YYYY/MM/
   MERRA-2    sub-directory    : GEOS_4x5/MERRA2/YYYY/MM/
   1x1 Emissions etc Data Dir  : /n/holylfs/EXTERNAL_REPOS/GEOS-CHEM/gcgrid/data/ExtData/GEOS_NATIVE/