README -- Describes contents of HEMCO/MERCURY/v2014-09/BrOx directory
12 Mar 2015
GEOS-Chem Support Team
geos-chem-support@g.harvard.edu


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

This directory contains Br and BrO concentrations that are needed by
the GEOS-Chem mercury simulations.  These netCDF files replace the binary
punch files that are read into GEOS-Chem module GeosCore/global_br_mod.F.


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

BrOx.GC.geos5.2x25.nc 

 -- Br and BrO mixing ratios from GEOS-Chem using Justin Parella's bromine 
    chemistry mechanism. (See "Bromine chemistry mechanism" on the 
    GEOS-Chem wiki.)

    Resolution  : GEOS-Chem 2 x 2.5 grid (144 x 72 boxes)
    Units       : ppbv
    Timestamps  : Monthly, 2007/01 thru 2007/12
    Compression : Level 1 (e.g. nccopy -d1)


BrOx.GMI.geos5.2x25.nc
  
 -- Br and BrO mixing ratios from GMI combo model.  These are regridded from 
    the Aura4 simulations of 2007 (courtesy J. Logan, I. Megretskaia). 

    Resolution  : GEOS-Chem 2 x 2.5 grid (144 x 72 boxes)
    Units       : pptv
    Timestamps  : Monthly, 1985/01 thru 1985/12
    Compression : Level 1 (e.g. nccopy -d1)


BrOx.TOMCAT_org.geos5.2x25.nc : 

 -- Br and BrO mixing ratios from University of Cambridge p-TOMCAT model 
    (courtesy Xin Yang). These are from a simulation with only organic Br-y
    precursors (no sea-salt aerosol). 

    Resolution  : GEOS-Chem 2 x 2.5 grid (144 x 72 boxes)
    Units       : pptv
    Timestamps  : Monthly, 1985/01 thru 1985/12
    Compression : Level 1 (e.g. nccopy -d1)


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

Mao, J., D.J. Jacob, M.J. Evans, J.R. Olson, X. Ren, W.H. Brune, J.M.S. Clair,
 J.D. Crounse, K.M. Spencer, M.R. Beaver, P.O. Wennberg, M.J. Cubison, J.L.
 Jimenez, A. Fried, P. Weibring, J.G. Walega, S.R. Hall, A.J. Weinheimer, R.C.
 Cohen, G. Chen, J.H. Crawford, L. Jaegle, J.A. Fisher, R.M. Yantosca, P.
 Le Sager, and C. Carouge, Chemistry of hydrogen oxide radicals (HOx) in the
 Arctic troposphere in spring, Atmos. Chem. Phys., 10, 5823-5838,
 doi:10.5194/acp-10-5823-2010, 2010.

Parrella, J.P., D.J. Jacob, Q. Liang, Y. Zhang, L.J. Mickley, B. Miller, 
 M.J. Evans, X. Yang, J.A. Pyle, N. Theys, and M. Van Roozendael, 
 Tropospheric bromine chemistry: implications for present and pre-industrial 
 ozone and mercury, Atmos. Chem. Phys., 12, 6,723-6,740, 2012.

Yang, X., Cox, R., Warwick, N., Pyle, J., Carver, G., O'Connor, F., and Savage,
 N.: Tropospheric bromine chemistry and its impacts on ozone: A model study, 
 J. Geophys. Res., 110, D23311, doi:10.1029/2005JD006244, 2005.


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

Bob Yantosca converted the bpch files in the prior GEOS_2x25/mercury_201007/
data directory to netCDF using the GAMAP routine BPCH2COARDS, following 
the procedure outlined here:

 http://wiki.geos-chem.org/Preparing_data_files_for_use_with_HEMCO#Converting_files_from_binary_punch_format_to_netCDF

The following NCO operations were then done to edit attributes for better
COARDS compliance:

 ncatted -a long_name,lev,o,c,"GEOS-Chem levels" BrOx.GC.geos5.2x25.nc
 ncrename -v IJ_AVG_S__Br,Br                     BrOx.GC.geos5.2x25.nc
 ncatted -a gamap_category,Br,o,c,"IJ-AVG-$"     BrOx.GC.geos5.2x25.nc
 ncrename -v IJ_AVG_S__BrO,BrO                   BrOx.GC.geos5.2x25.nc
 ncatted -a gamap_category,BrO,o,c,"IJ-AVG-$"    BrOx.GC.geos5.2x25.nc

 ncatted -a long_name,lev,o,c,"GEOS-Chem levels" BrOx.GMI.geos5.2x25.nc
 ncrename -v CHEM_L_S__LBRO2N,LBRO2N             BrOx.GMI.geos5.2x25.nc
 ncatted -a gamap_category,LBRO2N,o,c,"CHEM-L=$" BrOx.GMI.geos5.2x25.nc
 ncrename -v CHEM_L_S__LBRO2H,LBRO2H             BrOx.GMI.geos5.2x25.nc
 ncatted -a gamap_category,LBRO2H,o,c,"CHEM-L=$" BrOx.GMI.geos5.2x25.nc

 ncatted -a long_name,lev,o,c,"GEOS-Chem levels" BrOx.TOMCAT_org.geos5.2x25.nc
 ncrename -v CHEM_L_S__LBRO2N,LBRO2N             BrOx.TOMCAT_org.geos5.2x25.nc
 ncatted -a gamap_category,LBRO2N,o,c,"CHEM-L=$" BrOx.TOMCAT_org.geos5.2x25.nc
 ncrename -v CHEM_L_S__LBRO2H,LBRO2H             BrOx.TOMCAT_org.geos5.2x25.nc
 ncatted -a gamap_category,LBRO2H,o,c,"CHEM-L=$" BrOx.TOMCAT_org.geos5.2x25.nc