Summary

Description

The Level-1B (L1B) Radiance Product OML1BRUG (Version-3) from the Aura-OMI is now available to public (http://disc.gsfc.nasa.gov/Aura/OMI/oml1brug_v003.shtml) from the NASA GSFC Earth Sciences Data and Information Services Center (GES DISC). OMI calibrated and geolocated radiances for the channels in the UV1(264-311 nm), UV2 (307-383 nm) and VIS (349-504) regions, spectral irradiances, calibration measurements, and all derived geophysical atmospheric products are archived at the NASA Goddard DAAC. (The shortname for this OMI Level-1B Product is OML1BRUG) The lead algorithm scientist for this product is Dr. Marcel Dobber from the KNMI. This Radiance product contains geolocated Earth view spectral radiances from the UV detectors in the wavelength range of 264 to 383 nm. In the standard global measurement mode, OMI observes 60 ground pixels (13 km x 24 km at nadir) across the swath for each of the 557 channels of UV2 (307-383 nm) and 30 ground pixels (13 km x 48 km at nadir) for the 159 channels of UV1 (264-311 nm). Once a month in one orbit OMI performs dark measurements, it does not perform radiance measurements. In addition, OMI performs spatial zoom measurements one day per month. For that day, this product also contains UV2 measurements that are rebinned from the spatial zoom-in measurements. In original spatial zoom mode the nadir ground pixel size is 13 x 12 km and measurements are available only for the UV2 and VIS wavelengths (306 to 432 nm). OML1BRUG files are stored in EOS Hierarchical Data Format (HDF-EOS 2.4) which is based on HDF4. The radiance for the earth measurements (also referred as signal) and its precision are stored as a 16 bit mantissa and an 8-bit exponent. The signal can be computed using the equation: signal = signal_mantissa x 10 exponent . For the precision, the same exponent is used as for the signal. Each file contains data from the day lit portion of an orbit (~53 minutes) and is roughly 484 MB in size. There are approximately 14 orbits per day.