The recalibration is done using the method proposed by John et al. This paper presents the results of the recalibration of over 35 years of IR and WV channel measurements of JMA’s historical geostationary satellite, covering the period 1978–2016. To date, the time-series of measurements of IR and WV channels onboard JMA’s historical geostationary satellites were not recalibrated by JMA so as to produce a temporally homogenous data record for climate studies. Furthermore, his work considered each satellite separately and therefore inter-satellite homogeneity is not guaranteed. Unfortunately, the telemetry information and the recalibration coefficients, which were used in his study, are missing. He found that those data had large biases, 1–2 K during non-eclipse period and up to 6 K around midnight during eclipse period. For instance, Sasaki evaluated the operational calibration tables of the infrared channel onboard GMS-2 and GMS-3. On the other hand, only few attempts were made to recalibrate data from infrared (IR) and water vapor (WV) channels onboard JMA’s historical geostationary satellites so far. recalibrated visible channel data of Geostationary Metrological Satellite-5 (GMS-5)/Visible and Infrared Spin Scan Radiometer (VISSR) by using a radiative transfer simulation package with the Japanese 25-year Reanalysis (JRA-25) data, ground observation and MODIS data. ![]() JMA has been operating several geostationary meteorological satellites since 1978, collecting observations of the full Earth disk at least every six hours. Moreover, presented results contribute to the Inter-calibration of imager observations from time-series of geostationary satellites (IOGEO) project under the umbrella of the World Meteorological Organization (WMO) initiative Sustained and Coordinated Processing of Environmental Satellite data for Climate Monitoring (SCOPE-CM). The method used in this study is based on the principles developed within Global Space-based Inter-calibration System (GSICS). Finally, our analysis confirms the existence of errors due to atmospheric absorption contamination in the operational Spectral Response Function (SRF) of the WV channel of GMS-5. Overall, the magnitude of the biases for GMS-5, MTSAT-1R and MTSAT-2 were smaller than 0.3 K. ![]() However, for GMS-5, the amplitude of seasonal variation in bias was about 0.5 K. For the WV data of GOES-9, MTSAT-1R and MTSAT-2, no seasonal variations in radiometric biases were observed. The amplitudes of these seasonal variations range from 3 K for the earlier satellites to <0.4 K for the recent satellites (GMS-5, Geostationary Operational Environmental Satellite-9 (GOES-9), Multi-functional Transport Satellite-1R (MTSAT-1R) and MTSAT-2). This suggests that the sensors on GMS to GMS-4 were strongly affected by seasonal variations in solar illumination. For the IR data of the earlier satellites (Geostationary Metrological Satellite (GMS) to GMS-4) significant seasonal variations in radiometric biases were observed. This paper presents and evaluates the result of recalibration of longtime-series of IR (1978–2016) and WV (1995–2016) measurements from JMA’s historical geostationary satellites. Recalibration factors were computed from these pseudo imager radiance pairs. ![]() Pseudo geostationary imager radiances were computed from the infrared sounding measurements and regressed against the radiances from the geostationary satellites. The recalibration was performed using a common recalibration method developed by European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), which can be applied to the historical geostationary satellites to produce Fundamental Climate Data Records (FCDR). Infrared sounding measurements of the Infrared Atmospheric Sounding Interferometer (IASI), Atmospheric Infrared Sounder (AIRS), and High-resolution Infrared Radiation Sounder/2 (HIRS/2) instruments are used to recalibrate infrared (IR ~11 µm) channels and water vapor (WV ~6 µm) channels of the Visible and Infrared Spin Scan Radiometer (VISSR), Japanese Advanced Meteorological Imager (JAMI), and IMAGER instruments onboard the historical geostationary satellites of the Japan Meteorological Agency (JMA).
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