EarthProbe/TOMS March 1999 TOMS Earthprobe datasets are located in the following directory paths: data/ozYYYY/gaYYMMDD.ept (YYYY=1996 >>>>>) (EarthProbe still reporting data) 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 EarthProbe Data Products User's Guide, EARTHPROBE_USERGUIDE.PDF, available in the parent directory. A stub program, RDGRID.FOR may be used to read these datasets. The values are in 3 digit groups 111222333444555 Sample ozone value: 234 = 234 du 0 = fill value ------------------------------------------------------------------------ data/reflYYYY/gaYYMMDD.epr Daily reflectivity data. Format similar to that of ozone data. The vales are in 3 digit groups 111222333444555 Sample reflectivity value: _83 = 83% 999=fill value ----------------------------------------------------------------------- data/a1YYYY/gaYYMMDD.epa Daily aerosol data. Format similar to that of 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). There will soon be a corresponding data set of optical depths and single scattering albedos. 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. ------------------------------------------------------------------------ UV Erythemal Irradiance data/uvYYYY/gaYYMMDD.epe Daily uv data. RDGRID.FOR may be used to read these data but see 1README.UV and erynotes.pdf for information about interpreting/decoding the 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 ............................................................................ data/monthly_averages/gmYYMM.ept . 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 of aerosol, UV and reflectivity are also provided in directories located in a path structure similar to that for ozone averages. 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 .............................................................................. data/overpass/OVPxxx.ept A subset (seconds UT, latitude, longitude, total ozone, surface reflectivity, solar zenith angle,aerosol index, SOI index, etc) of EarthProbe data specific to a particular latitude-longitude location. xxx designates a numerical site location as listed in 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. .......................................................................... data/zonal_means/zm_month.ept and zmday_ YY.ept Zonal means files. File "zm_month.ept" contains monthly averages of zonal mean column ozone over each 5 degrees of latitude for each year of EarthProbe operation to date. Additional files, named "zmday_YY.ept" (YY=96, 97...) provide zonal means on a daily basis. At least 2/3 of possible data must be present for a zonal mean to be considered valid. 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 .......................................................................... If these EarthProbe/TOMS data are downloaded and used in publication, please give proper credit to the NASA/GSFC TOMS Ozone Processing Team (OPT). For more information on the EarthProbe/TOMS data set, contact Dr. Richard D. McPeters Code 916 NASA Goddard Space Flight Center Greenbelt, MD 20771 mcpeters@wrabbit.gsfc.nasa.gov ....................................................