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Microtops II Ozone Monitor & Sunphotometer


The Microtops II ozone monitor and sunphotometer is a 5 channel hand-held instrument for accurately measuring the ozone column (DU), ultra-violet irradiance, total atmospheric water vapour and aerosol optical thickness (AOT) at 1020nm.

The instrument includes calibrated internal temperature and pressure sensors and is supplied with a portable GPS and cable interface for automatic location setup and universal time recording. However, unlike the Facility's other MicroTops II sunphotometers this instrument has been configured with three ultraviolet detectors with narrow band precision at 305, 312 and 320nm and two near infrared detectors centred at 936nm and 1020nm.

Measured & Calculated Parameters

The following values can be read directly from the instrument or downloaded to a computer as a tab separated text file.

  • Date & time (UT)
  • GPS data - latitude, longitude, altitude
  • Solar zenith angle (SZA)
  • Pressure & temperature
  • Detector signals (mV)
  • Ratio of UV detector signals, 305/312 and 312/320
  • Standard deviation on detector signals during scan (only available from download file)
  • Irradiance values (W/m²)
  • Ozone column (in Dobson Units) calculated with 305 and 312nm data
  • Ozone column (in Dobson Units) calculated with 312 and 320nm data
  • Ozone column with compensation algorithm applied
  • Precipitable water column in cm
  • Aerosol optical thickness at 1020nm
  • Example Applications

  • Environmental monitoring
  • Pollution monitoring
  • Health care
  • Sunphotometry
  • Photobiology
  • Weather stations
  • Specification

    305.5 ±0.3 nm, 2.0 ±0.4 nm FWHM
    312.5 ±0.3 nm, 2.0 ±0.4 nm FWHM
    320.0 ±0.3 nm, 2.0 ±0.4 nm FWHM
    936 ±1.5 nm, 10 ±1.5 nm FWHM
    1020 ±1.5 nm, 10 ±1.5 nm FWHM
    Dynamic Range
    Field of View
    2.5 degrees
    max 0.002% FS
    Computer & GPS interface
    Power source
    4 x AA Alkaline batteries
    21 oz (600 grams)
    10 x 20 x 4.3cm
    Operating Environment
    0 to 50°C, no precipitation


  • Instrument guides
  • Log sheet
  • Sample data file with ozone calculations (Excel format)
  • Application notes on Solar Light Co. website
  • Manufacturer's user manual