Ozone Monitoring Instrument (OMI) / AURA April 2007 OMI datasets are located in the following directory paths: data/ozone/Yyyyy/L3_ozone_omi_yyyyMMDD.txt (yyyy=2004 through year present) Daily gridded (L3), ASCII files from year yyyy, month MM and day DD. The data in these ASCII files are in the format used for the Nimbus-7 and Earth Probe CD-ROM. Details of this format are explained in the EarthProbe Data Products User's Guide, EARTHPROBE_USERGUIDE.PDF, available in the parent directory (pub/eptoms). The values are in 3 digit groups 111222333444555 Sample ozone value: 234 = 234 du 0 = fill value ------------------------------------------------------------------------ data/reflectivity/Yyyyy/L3_reflc_omi_yyyyMMDD.txt 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/aerosol/Yyyyy/L3_aersl_omi_yyyyMMDD.txt NOTE: THE AEROSOL INDEX VALUES IN THESE FILES ARE THE OMI AEROSOL INDEX VALUES ADJUSTED DOWN BY ONE HALF N-VALUE TO BE CONSISTENT WITH THE TOMS DATA RECORD. Daily aerosol data. Format similar to that of ozone data. 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 ------------------------------------------------------------------------ data/monthly_averages/ozone/L3_ozavg_omi_yyyyMM.txt This directory contains gridded monthly (gm) averages of ozone data from year yyyy and month MM. At least 20 days of data must be available for monthly averages to be considered valid. 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/L2ovp_omto3_ecs2_NAME_xxx.txt A subset (seconds UT, latitude, longitude, total ozone, surface reflectivity, solar zenith angle,aerosol index, SOI index, etc) of OMI data specific to a particular latitude-longitude location. xxx designates a numerical site location and NAME is the location name. 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) 1-README_OVP_OMTO3.txt, in this directory, provides more information about the overpass files. ------------------------------------------------------------------------ data/zonal_means/ozone/zm_month_ozone_OM.txt and zmday_ozone_OM_yyyy.txt Zonal means files. File "zm_month_ozone_OM.txt" contains monthly averages of zonal mean column ozone over each 5 degrees of latitude for each year of OMI operation to date. Additional files, named "zmday_ozone_OM_yyyy.txt" 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. File "NN_month_ozone_OM.txt" contains the number of days of the month used in each 5-degree latitude band to calculate the monthly mean for each month and year. File "N_ozone_OM_yyyy.txt" contains the number of points used to calculate the daily zonal mean for each 5-degree latitude band as well as for the northern hemisphere, the southern hemisphere, and the entire globe for each day in year yyyy. The Fortran statements that wrote the header and data records of file zm_month_ozone_OM.txt 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_ozone_OM_yyyy.txt files is: write(21,'(A12,F9.3,1X,36F6.1,3X,3F6.1)') date,yd,zmd ------------------------------------------------------------------------ For more information on the OMI data set, contact Dr. Richard D. McPeters Code 613.3 NASA Goddard Space Flight Center Greenbelt, MD 20771 mcpeters@wrabbit.gsfc.nasa.gov ------------------------------------------------------------------------