Fig.1: Total ozone distribution in the time period 1. to 3. October 1996 as measured by the GOME instrument. The 'ozone hole', an area with total ozone values below 220 Dobson Units (DU), nearly completely covers Antarctica.
Ozone Animations
Instrument
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On the 21st of April 1995 the Global Ozone Monitoring Experiment (GOME) was successfully launched on board of the European Space Agency's (ESA) second Earth Remote Sensing Satellite (ERS-2). GOME is a four-channel double spectrometer with diode array detectors. It measures the solar radiation scattered by the system earth-atmosphere in nadir viewing geometry in the wavelength range of 240 - 790 nm with a spectral resolution of 0.2 - 0.4 nm. The direct solar radiation is measured as well, mainly for the normalization of the Earth-shine spectra.
Fig.1: Total ozone distribution in the time period 1. to 3. October 1996
as measured by the GOME instrument. The 'ozone hole', an area
with total ozone values below 220 Dobson Units (DU),
nearly completely covers Antarctica.
The main scientific objective of the GOME mission is the monitoring of global total ozone distributions. In this context the high spectral resolution of GOME for the first time allows the application of the Differential Optical Absorption Spectroscopy (DOAS) trace gas retrieval method to satellite measurements. Other important atmospheric trace gases, e.g. NO2, OClO (see plots below) and BrO, can be detected as well. In addition informations about clouds, aerosols and the Earth's surface spectral reflectance can be obtained. Besides the total ozone retrievals height resolved ozone information can also be derived.
Fig.2: OClO fit residual of a single GOME measurement. The
``smooth'' curve shows the OClO reference spectrum as measured in the
lab. The second curve is a GOME measurement after subtraction of
several components taken into account in the fitting process.
Fig. 3: OClO 'slant columns' derived from GOME measurements over
Antarctica using the DOAS fitting method. The solid lines are showing
slant columns that have been computed with our radiative transfer code
GOMETRAN assuming different vertical OClO columns. The increase of
OClO with increasing solar zenith angle is mainly due to the following
two effects: (i) decrease of OClO photolysis with increasing darkness
and (ii) deeper penetration into the polar vortex (ozone hole
conditions).
Operational processing of GOME measurements to GOME data products (Earthshine radiance, solar irradiance, ozone and NO2 total column amounts) is done at the DLR-DFD (German Aerospace Research Establishment - German Remote Sensing Data Center) in Oberpfaffenhofen near Munich, Germany. GOME user support and latest GOME news are available via ESRIN (ESA's European Space Research Institute), Frascati, Italy or ESRIN II.
Suggested Reading:
Burrows, J.P. et al., 1999: The Global Ozone Monitoring Experiment (GOME): Mission Concept and First Scientific Results, J. Atmos. Sci. 56, 151-175. (preprint, postscript, 9.8Mb, and compressed preprint, 1.5Mb, available).
ERSCONF, 1997: Proceedings of the 3rd ERS Conference , ESA Special Publication 414, Vol. II, Florence, Italy, 17-21 March 1997.
GOMESCIENCE, 1993: GOME Interim Science Report, ESA Special Publication 1151, ESA/ESTEC, Nordwijk, The Netherlands.
GOMEMANUAL, 1995: GOME Users Manual, ESA Special Publication 1182, ESA/ESTEC, Nordwijk, The Netherlands.
GOMEVAL, 1996: Geophysical Validation Campaign Workshop Proceedings, ESA WPP-108, ESA/ESTEC, Nordwijk, The Netherlands.
see University of Bremen GOME papers
see also ESA/ESRIN ERS homepage
Ozone Animations
Instrument
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