Re-calibration for infrared channels of previous JMA GEO satellites

Background

JMA has re-calibrated conventional infrared (IR; approx. 11 μm) and water vapor (WV; approx. 6 μm) channel data from the imagers on the GMS,-2,-3,-4,-5, GOES-9, MTSAT-1R and -2 satellites to support climate research conducted in collaboration with the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The work contributes to the Inter-calibration of passive imager observations from time-series of geo stationary satellites (IOGEO) project conducted under WMO′s Sustained, Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM) initiative established in 2008. The project involves collaboration by space agencies and operators of environmental satellite systems in various countries to coordinate and facilitate international activities for the generation of Climate Data Records (CDRs) from multi-agency satellite data. IOGEO is intended to support the establishment of spatially and temporally homogeneous radiance data from all historical geostationary meteorological satellites.

Methodology

Pseudo geostationary imager radiances were computed using data from infrared sounding (Infrared Atmospheric Sounding Interferometer (IASI), Atmospheric Infrared Sounder (AIRS) and High-resolution Infrared Radiation Sounder/2 (HIRS/2) instruments) and regressed against radiance values from geostationary satellite observation. Recalibration factors were computed from these radiance pairs. The work was summarized by John et al. (2019) and Tabata et al. (2019).

Outcomes

  • Daily correction parameters (slope and offset) for infrared channels of imagers on the GMS,-2,-3,-4,-5, GOES-9, MTSAT-1R and -2 satellites
  • Spectral Band Difference Adjustment Factors (SBAF) to mitigate differences among GEO imagers

Notes

  • One pair (slope and offset) of correction parameters is introduced for each day and for each channel.
  • Correction parameters for some days have not been calculated due to missing data.
  • Navigation error correction has not been applied.
  • The uncertainties of correction for very cold brightness temperature data are potentially bigger than those for warm data because the number of collocation data between the infrared sounding measurements and geostationary imagers is not enough much for cold area.
  • Sensor Planck functions, which is suggested by Tahara (2008), are used for applying the correction parameters.
  • Bréon et al. (1999) pointed out that the original Spectral Response Function (SRF) of the GMS-5/VISSR WV channel provided by the satellite sensor vendor had been contaminated by atmospheric absorption, and suggested corrected SRF by using the atmospheric transmission model. Coefficients for the sensor Planck functions and SBAF for the SRF suggested by Bréon et al. (1999) were created.

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References