README -- describes contents of TOMS_200701 14 Jan 2009 Bob Yantosca, Philippe Le Sager, and Claire Carouge geos-chem-support@g.harvard.edu Files: ------- TOMS_O3col_1979.geos.4x5 -- Binary punch (bpch) files containing 12 months TOMS_O3col_1980.geos.4x5 of TOMS/SBUV data on the GEOS-Chem 4x5 grid. TOMS_O3col_1981.geos.4x5 TOMS_O3col_1982.geos.4x5 The data comes from the raw data file TOMS_O3col_1983.geos.4x5 "toms_sbuv.v8.mod_v3.78-06.5x10.rev3.txt", TOMS_O3col_1984.geos.4x5 which is available from the website TOMS_O3col_1985.geos.4x5 hyperion.gsfc.nasa.gov/Data_services/merged/data/ TOMS_O3col_1986.geos.4x5 TOMS_O3col_1987.geos.4x5 The data are then split into individual monthly TOMS_O3col_1988.geos.4x5 files with ~bmy/archive/data/IDL/cut.pro. TOMS_O3col_1989.geos.4x5 TOMS_O3col_1990.geos.4x5 Then the data are regridded and saved to binary TOMS_O3col_1991.geos.4x5 punch format with the IDL program TOMS_O3col_1992.geos.4x5 ~bmy/archive/data/IDL/reader_10x5_togcap.pro. TOMS_O3col_1993.geos.4x5 Currently we have data from 1979-2005. More TOMS_O3col_1994.geos.4x5 data may be added as it becomes available. TOMS_O3col_1995.geos.4x5 TOMS_O3col_1996.geos.4x5 These data files are used by "toms_mod.f" TOMS_O3col_1997.geos.4x5 of the GEOS-Chem source code. TOMS_O3col_1998.geos.4x5 TOMS_O3col_1999.geos.4x5 TOMS_O3col_2000.geos.4x5 TOMS_O3col_2001.geos.4x5 TOMS_O3col_2002.geos.4x5 TOMS_O3col_2003.geos.4x5 TOMS_O3col_2004.geos.4x5 TOMS_O3col_2006.geos.4x5 TOMS_O3col_2007.geos.4x5 Data source and version: ------------------------- 1979 - 1985 are taken from: http://code916.gsfc.nasa.gov/Data_services/merged/index.html TOMS/SBUV MERGED TOTAL OZONE DATA, Version 8, Revision 3. Resolution: 5 x 10 deg. Contact person for the merged data product: Stacey Hollandsworth Frith (smh@hyperion.gsfc.nasa.gov) 2006 - 2007 are taken from http://code916.gsfc.nasa.gov/Data_services/merged/index.html Version 8 Merged Ozone Data Sets Revision 04 DATA THROUGH: SEP 2008 LAST MODIFIED: 20 OCT 2008 Methodology: ------------------------- FAST-J comes with its own default O3 column climatology (from McPeters 1992 & Nagatani 1991), which is stored in the input file "jv_atms.dat". These "FAST-J default" O3 columns are used in the computation of the actinic flux and other optical quantities for the FAST-J photolysis. The TOMS/SBUV O3 columns and 1/2-monthly O3 trends (contained in the TOMS_200701 directory) are read to GEOS-Chem by routine READ_TOMS in "toms_mod.f". Missing values (i.e. locations where there are no data) in the TOMS/SBUV O3 columns are defined by the flag -999. After being read from disk in routine READ_TOMS, the TOMS/SBUV O3 data are then passed to the FAST-J routine "set_prof.f". In "set_prof.f", a test is done to make sure that the TOMS/SBUV O3 columns and 1/2-monthly trends do not have any missing values for (lat,lon) location for the given month. If so, then the TOMS/SBUV O3 column data is interpolated to the current day and is used to weight the "FAST-J default" O3 column. This essentially "forces" the "FAST-J default" O3 column values to better match the observations, as defined by TOMS/SBUV. If there are no TOMS/SBUV O3 columns (and 1/2-monthly trends) at a (lat,lon) location for given month, then FAST-J will revert to its own "default" climatology for that location and month. Therefore, the TOMS O3 can be thought of as an "overlay" data -- it is only used if it exists. Note that there are no TOMS O3 columns at the higher latitudes. At these latitudes, the code will revert to using the "FAST-J default" O3 columns. As of February 2007, we have TOMS/SBUV data for 1979 thru 2005. 2006 TOMS/SBUV data is incomplete as of this writing. For years 2006 and onward, we use 2005 TOMS O3 columns. This methodology was originally adopted by Mat Evans. Symeon Koumoutsaris was responsible for creating the downloading and processing the TOMS O3 data files from 1979 thru 2005 in the TOMS_200701 directory.