README -- Describes contents of HEMCO/CO2/v2014-09/
23 Feb 2015
GEOS-Chem Support Team
geos-chem-support@g.harvard.edu


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

From the GEOS-Chem wiki:

   The original GEOS-Chem CO2 simulation was developed by Parv Suntharalingam 
   (Suntharalingam et al., 2003; 2004), now at the University of East Anglia. 
   A major update to the CO2 simulation has been developed by Ray Nassar (now 
   at Environment Canada) and Dylan B.A. Jones of the University of Toronto 
   (Nassar et al., 2010). This update was delivered to the GEOS-Chem software 
   development team at Harvard on 2010 April 1.
   
   The update retains the original six CO2 fluxes: fossil fuel, ocean exchange, 
   biomass burning, biofuel burning, balanced terrestrial exchange (CASA) and 
   net annual terrestrial exchange. New inventories are available as options 
   for some of these fluxes and other new fluxes have been added such as CO2 
   emissions from international shipping and aviation. There is also now an 
   optional feature to include CO2 production from the oxidation of CO, CH4 
   and NMVOCs. This chemical source concept was first highlighted by Enting 
   and Mansbridge (1991). Although a few attempts have been made by other 
   groups in the past, this implementation will make GEOS-Chem the only 
   3-D global model in current use to account for the chemical production of
   CO2. The GEOS-Chem implementation uses an approach similar to that 
   described in Suntharalingam et al. (2005), with some updated year-specific 
   numbers and some other modifications described in Nassar et al. (2010).
   
   In Feb 2010, the CDIAC fossil fuel emissions inventory was updated. Files 
   containing annual and monthly emissions of CO2 are now available for the 
   years 1979-2009. 

The original data files were in stored in binary punch data format.  
Christoph Keller converted these to COARDS-compliant netCDF for compatibility
with HEMCO.


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


Net_terrestrial_exch_5.29Pg.generic.1x1.nc

 -- Net terrestrial exchange based on Transcom 3 climatology (1991-2000),
    minus the GFEDv2 climatology (1997-2007). 

    Resolution  : GENERIC 1 x 1 grid
    Units       : kg m-2 s-1
    Timestamps  : 2000/01/01
    Compression : Level 1 (e.g. nccopy -d1)


biofuel_CO2.geos.1x1-1995.nc

 -- Biofuel emissions of CO2 from Ray Nassar (see original README below).

    Resolution  : GENERIC 1 x 1 grid
    Units       : kg m-2 s-1
    Timestamps  : 1995/01/01
    Compression : Level 1 (e.g. nccopy -d1)


Other data sets for the CO simulation are stored in subfolders.
Please see the corresponding README files for more information:

./BBIO/README   : Describes balanced biosphere data

./CHEM/README   : Describes chemical source data

./FOSSIL/README : Describes fossil fuel emission data

./OCEAN/README  : Describes ocean exchange data 


References:
===============================================================================

Baker, D. F., et al., "TransCom 3 inversion intercomparison: Impact of 
  transport model errors on the interannual variability of regional CO2 
  fluxes", 1988-2003, __Global Biogeochem. Cycles__, 20, GB1002, 
  doi:10.1029/2004GB002439, 2006. 


Also see: 

   http://wiki.geos-chem.org/CO2_simulation#References


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The biofuel bpch files were created by Ray Nassar 2010 March 11.

It was based on the following ASCII data (developing world only - Table 13 
in Yevich and Logan):

* The woodfuels file is called WDF.1x1 and total of all 1x1 boxes is 1323.17 Tg
* The residue/dung biofuels file is CMB.1x1 and total is              732.82 Tg 

The following component was not included since this is now better represented 
by GFED.

* The burning-in-fields file   is BIF.1x1 and totals                  406.36 Tg

Emission Factors (CO2 g/kg) used for CO2 were:

Woodfuel            1467 / 0.45  (Table 22)
Burn-in-fields      1132 / 0.40  (Table 24)
Residue             1192 / 0.40  (Table 22)
Dung                1010 / 0.35  (Table 22)
Residue and Dung    1161.5 / 0.3916 based on weighting in Table 13 
(Residue 239 Tg + Dung 48 Tg)

Note: The above includes the factor for conversion of g DM to g C (Appendix B)

Scaling the 1985 values to 1995 values was done for 3 separate regions 
based on Table 16.

180-30W Latin America
30W-60E Africa (including Middle East)
60-180E Asia

REFERENCES

Yevich, R. and J.A. Logan, An assessment of biofuel use and burning of
agricultural waste in the developing world, Global Biogeochemical Cycles, 
17(4), 1095, doi:10.1029/2002GB00152 (2003).