air quality assessment & management
Reference and User Manual
      AirWare   On-line Reference Manual
        Release Level 7.0
        Revision Level beta
        Release Date 2015 03

      Last modified on:   Saturday, 5-Dec-15 10:08 CET

      CAMx Ozone modeling: pre-processors

      CAMx V6.20 uses TOMS ozone column depth file ("") and the photolysis preprocessors (o3map and tuv4.8.camx6.20).

      o3map:   Used to prepare ozone column input file for TUV and CAMx: o3map-6may13.tgz o3map comes from ENVIRON.

      TUV:   Program to develop clear-sky photolysis rate inputs needed for CAMx: tuv4.8-camx5.41-09nov12.tgz TUV originates from UCAR (

      TOMS data (ionput to o3map):   TOMS files are ozone column data, which are a measure of total-column ozone, which is dominated by ozone in the stratospheric ozone layer. Ozone column determines (together with solar zenith angle and haze) the photolysis rates. Better estimation of photolysis rates improve chemistry dependent results.

      Total ozone column data are downloaded from

      • Scenario analysis: Uses monthly average data of the years 2007-2014.
      • Forecasts: regular downloads latest available daily data (usually of the day before yesterday).

      README for o3map:  

      • The /ozone/ directory contains daily data for the whole globe. Daily data will include gaps of missing data due to the limited coverage of the OMI instrument. These gaps are automatically filled by the O3MAP program using interpolation.
      • The /monthly_averages/ozone/ directory contains monthly data for the whole globe. Monthly data does not include data gaps."

      Daily data are available from 2004-10-01 until the day before yesterday. Forecast uses the latest available data.

      Total ozone column varies more with the season, so the error should not be very large when using data which are some days old.

      Monthly average data are available from Oct 2004 until December of last year. CAMx standard uses monthly data, if available, daily data otherwise.

      CAMx User’s Guide Version 6.2, p26:
      NOTE: gaps in day-specific ozone column data at low latitudes, and high latitudes during winter, may result in zero values over portions of the modeling grid. This results from the inability of polar-orbiting satellite instruments to cover the entire globe on a daily basis. The user may instead use seasonal-average ozone column files (no data gaps); alternatively, O3MAP provides an option to fill these day-specific gaps with an average determined from valid data processed for the extraction domain.

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