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Data DescriptionGlobal Ozone Monitoring Experiment-2 (GOME-2) Total Ozone Level 2 Granules - The GOME-2 total ozone retrieval algorithm is based on OMI/TOMS (Ozone Monitoring Instrument / Total Ozone Mapping Spectrometer) V8 algorithm, which is a three-step process of successive estimation improvement. The algorithm uses a pair of wavelengths 331nm and 318nm (340nm and 331nm for high solar zenith angle) to derive total ozone and surface reflectivity. It first calculates N-value at the pair of wavelengths using input radiance/irradiance from GOME-2 level 1b data. With its geo-reference information, such as latitude, longitude, solar zenith angle, etc., the measured N-value is compared with pre-calculated N-value to derive the step-one total ozone and reflectivity. The pre-calculated N-value is generated by using a forward radiative transfer model. In order to obtain step-two ozone, the profiles of ozone and temperature climatologies are then applied at all levels to account for seasonal and latitudinal variations in profile shape. In the last step, the step-two ozone estimation is modified to correct for wavelength dependent effects (tropospheric aerosol and sun glint) and local upper level profile shape effects. The algorithm writes out all the retrieval variables and corresponding geo-referenced information to a Product Master File (PMF) at the end of each scan process. The PMF files are available in sequential binary format for each three minute granule.
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