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Vatnajokull Interferometric Image, Oct 18th-19th 1995
Corrected Vatnajokull Interferometric Image, Oct 18th-19th 1995
Vatnajokull Interferometric Image, Oct 22-23 1995
Vatnajokull Interferometric Image, Oct 22-23, 1995
Vatnajokull Interferometric Image, Oct 9-10 1995
Vatnajokull Interferometric Image, corrected, Oct 18th-19th 1995
SAR performance with mono-gyroscope piloting (nominal operations)
GOME long-term performance analyses
PRARE and Orbit Determination (ERS-1&2 satellites)
ERS Tandem Mission - Examples of Zurich & Surroundings (1995)
Columbia, Interferometric Land Use Image
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GOME long-term performance analyses

GOME calibration and performance studies are being carried out by ESA in cooperation with various institutes and companies, as listed below.

  • Deutsches Zentrum für Luft und Raumfahrt, D (DLR)
  • University of Bremen, D (IFE)
  • Royal Netherlands Meteorological Institute (KNMI)
  • Space Research Organization Netherlands (SRON)
  • Smithsonian Centre for Astrophysics, MA, USA

GOME diffuser and dark signal trends (November 1999)

The analysis on the GOME diffuser plate stability and the detector array dark signal measurements was updated for the period July 1995 - September 1999. During the period of about ~4.5 years no significant changes of the diffuser plate could be detected. The analysis of the dark signal measurements shows a linear increase of the leakage current of about 13-14 % per year. See the document.

GOME Degradation files (September 1999)

To be used when working with specific options of the GOME Level 1 extraction software (gdp01_ex) Version 2.0.

Quantitative spectroscopy for the analysis of GOME data (Chance, Florence 1997)

A prerequisite for successful retrieval of trace gas vertical columns from GOME data is the availability of accurate quantitative spectroscopic and light scattering knowledge. Quantitative spectroscopic knowledge concerns the high-resolution temperature-dependent absorption cross section of trace gases. Light scattering knowledge includes the Rayleigh scattering cross section and phase function in the spectral interval 200-1000 nm; the Ring effect (inelastic light scattering) cross section and phase function, as determined from NO2 and O2 molecular parameters; the line parameters for calculations of absorption in band A of molecular oxygen (used in the GOME cloud filtering algorithm). Additionally the solar irradiance reference spectrum has to be accurately known.
In the implementation of the GOME data processing, all the above mentioned quantities, have been measured by means of the GOME flight model, at a moderate spectral resolution. This implies that the instrument response is known quite accurately and is supposed to be stable in space conditions. Alternatively, they can be measured with a higher spectral resolution and a high accuracy (in vacuum conditions), and then convolved to GOME spectral resolution. Such determinations are being carried out. Data are already available for solar irradiance, Rayleigh scattering, Ring effect and NO2 absorption cross section (and have been implemented in the latest GOME product Level-2, 2.0 version); investigations relative to O3, O2, BrO and H2O are under way, whereas improvements, relative to OClO, SO2, NO and O4 are needed.

GOME wavelength calibration using solar and atmospheric spectra (Caspar and Chance, Florence 1997)

GOME spectral calibration is based on the spectral lines emitted by a PtNeCr lamp. These lines have turned out to be stable to 0.02-0.04 GOME pixel, when measured in orbit over a typical range of instrument temperature variations. The temperature needed in the calibration procedure is taken at the predisperser prism: it has been argued that this can introduce additional uncertainties. Two alternative calibration methods are being investigated, which make use of the Fraunhofer lines present in, both, solar irradiance and earth radiance spectra. Both methods show an improved spectral calibration accuracy < 0.002 nm (< 0.02 GOME pixel), in most of the GOME spectral range, especially in the spectral regions where O3, NO2, BrO and OClO gas concentrations are measured. Still additional studies are needed before implementing any procedure at operational level.

GOME diffuser and dark signal trends (Pemberton, Florence 1997)

(dataset: July 1995 - January 1997)
An analysis of the GOME diffuser plate stability and of the detector array dark signal measurements has been performed. No significant change of the diffuser plate has been detected. From dark signal measurements analysis a linear increase of the leakage current - of about 15% per year - has been observed.

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry