README -- describes contents of TOMS_200906 27 Feb 2012 GEOS-Chem Support Team geos-chem-support@g.harvard.edu Files: ------- TOMS_O3col_1971.geos.2x25 -- Binary punch (bpch) files containing 12 months TOMS_O3col_1972.geos.2x25 of TOMS/SBUV data on the GEOS-Chem 2x25 grid. TOMS_O3col_1973.geos.2x25 TOMS_O3col_1974.geos.2x25 The data comes from the raw data file TOMS_O3col_1975.geos.2x25 "toms_sbuv.v8.mod_v3.70-11.5x10.rev5.txt" TOMS_O3col_1976.geos.2x25 which is available from the website TOMS_O3col_1977.geos.2x25 http://acdb-ext.gsfc.nasa.gov/Data_services/merged/ TOMS_O3col_1978.geos.2x25 TOMS_O3col_1979.geos.2x25 The data are then split into individual monthly TOMS_O3col_1980.geos.2x25 files with ~bmy/archive/data/IDL/cut.pro. TOMS_O3col_1981.geos.2x25 TOMS_O3col_1982.geos.2x25 Then the data are regridded and saved to binary TOMS_O3col_1983.geos.2x25 punch format with the IDL program TOMS_O3col_1984.geos.2x25 ~bmy/archive/data/IDL/reader_10x5.pro. TOMS_O3col_1985.geos.2x25 TOMS_O3col_1986.geos.2x25 Currently we have data from 1971-2010. More TOMS_O3col_1987.geos.2x25 data may be added as it becomes available. TOMS_O3col_1988.geos.2x25 TOMS_O3col_1989.geos.2x25 These data files are used by "toms_mod.f" TOMS_O3col_1990.geos.2x25 of the GEOS-Chem source code. TOMS_O3col_1991.geos.2x25 TOMS_O3col_1992.geos.2x25 This data was processed by Jenny Fisher TOMS_O3col_1993.geos.2x25 (jafisher@fas.harvard.edu) TOMS_O3col_1994.geos.2x25 TOMS_O3col_1995.geos.2x25 TOMS_O3col_1996.geos.2x25 TOMS_O3col_1997.geos.2x25 TOMS_O3col_1998.geos.2x25 TOMS_O3col_1999.geos.2x25 TOMS_O3col_2000.geos.2x25 TOMS_O3col_2001.geos.2x25 TOMS_O3col_2002.geos.2x25 TOMS_O3col_2003.geos.2x25 TOMS_O3col_2004.geos.2x25 TOMS_O3col_2005.geos.2x25 TOMS_O3col_2006.geos.2x25 TOMS_O3col_2007.geos.2x25 TOMS_O3col_2008.geos.2x25 TOMS_O3col_2009.geos.2x25 TOMS_O3col_2010.geos.2x25 Data source and version: ------------------------- Version 8 Merged Ozone Data Sets Total Ozone Revision 05 DATA THROUGH: DEC 2011 LAST MODIFIED: 25 JAN 2011 http://acdb-ext.gsfc.nasa.gov/Data_services/merged/index.html TOMS/SBUV MERGED TOTAL OZONE DATA, Version 8, Revision 5. Resolution: 5 x 10 deg. * Includes reprocessed N16 and N17 SBUV/2 data using latest calibration. * OMI data updated from Collection 2 to Collection 3. * New offsets derived based on revised data sets. * 1970-1972 N4 BUV data added with no adjustments. User may wish to apply offset based on Comparisons between BUV and Dobson Measurements. Responsible NASA official: Dr. Richard Stolarski (Richard.S.Stolarski@nasa.gov) Stacey Frith (Stacey.M.Frith@nasa.gov ) 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/SBUV O3 columns at the higher latitudes (i.e. during polar night). At these locations, the code will revert to using the "FAST-J default" O3 columns. But because we don't call FAST-J in boxes where it is night, this essentially means that we have replaced the entire FAST-J O3 column climatology with the TOMS/SBUV O3 column product. As of Feb 2012, we have TOMS/SBUV data for 1971 thru 2011. 2012 data is incomplete as of this writing. Jan 2012 data is necessary to process 2011 data, so only 1971-2010 data have been processed. This methodology was originally adopted by Mat Evans.