ADEOS/TOMS 
July 1999
 
data/ozYYYY/gaYYMMDD.a1t (YYYY = 1996, 1997)
     Daily gridded(g), ASCII (a) files from year YY, month MM and day DD.
     The data in these ASCII files are in the format used for the 
     Nimbus-7 and Meteor-3 CD-ROM. Details of this format are explained in the
     ADEOS Data Products User's Guide, ADEOS_USERGUIDE.PDF, available in
     the parent directory of this path.

A Fortran stub program, RDGRID.FOR, for reading the ASCII gridded ozone,
reflectivity, and aerosol data files, is provided in this directory. 

     The values are in 3 digit groups 111222333444555
     Sample value:   234 = 234 du         0 = fill data
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data/reflYYYY/gaYYMMDD.a1r 
     Daily gridded reflectivity data. Format is like that for ozone data.

     The values are in 3 digit groups 111222333444555
     Sample value:   _83 = 83%          999 = fill value

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data/aiYYYY/gaYYMMDD.a1a      
     Daily gridded aerosol data. Format is like that for ozone data.

     The data are an aerosol index formed directly from the measured
     radiances in two TOMS channels. Positive values generally represent
     absorbing aerosols (dust and smoke) while negative values represent
     nonabsorbing aerosols. The identification is not perfect because of
     geophysical reasons (e.g., aerosol too low to the ground).
     
     The values are in 3 digit groups 111222333444555
     The numbers have been multiplied by 10
     
     --1 = 0.1    -11=1.1     111=11.1
     999 = missing or bad data
     --  stands for blanks
     
References:

Herman, J.R., P.K. Bhartia, O. Torres, C. Hsu, C. Seftor, E. Celarier,
Global Distribution of UV-Absorbing Aerosols from Nimbus-7/TOMS Data,
J. Geophys. Res., 102, 16, 911-16, 922, 1997.

Torres, O. P.K. Bhartia, J.R. Herman, Z. Ahmad, and J. Gleason,
Derivation of aerosol properties from satellite measurements of
backscattered ultraviolet radiation: Theoretical basis,
J. Geophys. Res. 103, 17099-17110, 1998.     

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data/uvYYYY/gaYYMMDD.a1e        
     Daily gridded erythemal uv data. These files may be read by the 
     format statement in RDGRID.FOR, but see 1README.UV and erynotes.pdf for 
     information about interpretation/decoding  of UV data file format.

     The values are in 3 digit groups 111222333444555
     
     123 = 2.3x10^1 J/m2      -23 = 2.3         --3 = 0.3
     999 = missing or bad data

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data/monthly_averages/ozone/gmYYMM.a1t
     This directory contains gridded monthly (gm) averages of ozone 
     data from year YY and month MM. At least 20 days of data must be 
     available for monthly averages to be considered valid.
     
     Monthly averages for aerosol, UV and reflectivity are also provided in
     directories located in a path structure similar to that for ozone.   

The Fortran statements that wrote the data records of these monthly files are:

           DO 570 IL=1,180
           DO 560 jj=1,288
      560  OZONE(JJ)=ozav(JJ,IL)
           write(21,'(1X,25I3)') (OZONE(jj),jj=1,275)
           write(21,'(1X,13I3,1A17)') (OZONE(jj),jj=276,288), latlab(IL)
      570  CONTINUE

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data/overpass/OVPxxx.a1t
     A subset (seconds UT, latitude, longitude, total ozone, surface 
     reflectivity, solar zenith angle, aerosol index and SOI index) of 
     ADEOS data specific to a particular latitude-longitude location. 
     xxx designates a numerical site location as listed in the ASCII file 
     "1Sitelist" in this directory.

Fortran statements that can be used to read the 1st header record and the
data records in the OVPxxx files are the following:

For the header record:

           CHARACTER*28 site_name
           INTEGER*4    site_id, site_alt
           REAL*4       site_lat, site_lon
           Read(lun,2) site_name, site_id, site_lat,site_lon, site_alt
         2 Format(A30,4X,I3,7X,F7.2,7X,F7.2,7X,I4)

and for the data records:
           Format(F7.1,1X,I4,1X,I3,1X,I5,2X,I2,1X,F6.2,1X,F7.2,1X,
              I3,1X,I3,1X,F5.2,1X,F5.1,1X,F5.1,1X,F6.2,1X,I4)
    
1README, in this directory, provides more information about the
OVPxxx files.

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data/zonal_means/ozone/zm_month.ept and zmday_YY.ept
     Zonal means files. File zm_month.a1t contains monthly averages of 
     zonal mean column ozone over each 5 degrees of latitude for each 
     year of ADEOS operation. 
     
     Additional files, named "zmday_YY.a1t" 
     (YY=96, 97) provide ozone zonal means on a daily basis.

     At least 2/3 of the possible data must be present for a zonal
     mean to be considered valid.

     Zonal means for aerosol, UV and reflectivity are also provided in
     directories located in a similar path structure as that for ozone.

The Fortran statements that wrote the header and data records of file
zm_month are the following:

           CHARACTER*69 MONLAB
           Data MONLAB/'Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep
          & Oct   Nov   Dec'/
           do 20 j=1,37
           lat(j)=-95 + 5*j
        20 continue
           write(22,'(8x,A69)') MONLAB
           DO 300 IZ=1,36
           write(22,'(I3,I4,12f6.1)') lat(IZ),lat(IZ+1),(ozm(IM,IZ),IM=1,12)
      300  CONTINUE
           write(22,'(I3,I4,12f6.1)') -65,0,(ozm(IM,37),IM=1,12)
           write(22,'(I3,I4,12f6.1)') 0,65,(ozm(IM,38),IM=1,12)
           write(22,'(I3,I4,12f6.1)') -65,65,(ozm(IM,39),IM=1,12)

The Fortran statement that wrote the data records of the zmday_YY files is:

           write(21,'(A12,F9.3,1X,36F6.1,3X,3F6.1)') date,yd,zmd

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If these ADEOS/TOMS data are downloaded and used in publication, please 
give proper credit to the NASA/GSFC Ozone Processing Team.

For more information on the ADEOS/TOMS dataset, contact

     Dr. Arlin Krueger
     Code 916
     NASA Goddard Space Flight Center
     Greenbelt, Md. 20771
     krueger@chapman.gsfc.nasa.gov