GRWG/GDWG Web Meeting 2018-05-08 11:00-13:00 UTC
GSICS Web Meeting on GEO-GEO comparison and contribution to IOGEO
- Rob Roebeling (EUMETSAT) – GEO-Ring: SCOPE-CM IOGEO (partly including FIDUCEO)
- Tasuku Tabata (JMA) - GEO-GEO IR/WV channel radiance comparison
- Masaya Takahashi (JMA) – GEO-GEO benefits and RGB Composites
- Hyeji Yang (KMA) - GEO-GEO (COMS vs H-8) inter-comparison for investigating the diurnal variation
Chair: Dohyeong Kim (KMA)
EUMETSAT: Rob Roebeling, Tim Hewison, Sebastien Wagner
JMA: Masaya Takahashi, Yusuke Yogo, Tasuku Tabata and Kazuki Kodera
KMA: Dohyeong Kim, Hyeji Yang, Eunkyu Kim
NASA: Dave Doelling
NOAA: Fred Wu, Likun Wang, Manik Bali
Rob Roebelling of EUMETSAT reported the status of joint SCOPE-CM (Climate Monitoring) IOGEO and GSICS inter-comparison of reference sensor equivalent (re-calibrated) radiances from WV, IR (and VIS) channels on heritage geostationary satellites. And he also reported that mostly GSICS calibrated data except for METEOSAT-10 of GSICS and IOGEO calibrated data, have been uploaded to the common FTP site provided by EUMETSAT. He introduced the related recalibrated work at EUMETSAT showing the differences between sensor equivalent calibration and reference sensor normalized calibration of METEOSAT First Generation radiances for the water vapor and infrared channel. In case of visible channel, he showed the differences of drift of calibration coefficient over desert and ocean using between prelaunch and FIDUCEO reconstructed spectral response function for the METEOSAT series (Met-2 to Met-7). He finally introduced the planning of 2018-2019 for recalibration geostationary satellites, and also seeked for collaborative activities to perform the GEO-GEO inter-comparison of GSICS and IOGEO recalibrated IR, WV (and VIS) radiances as visiting scientists at EUMETSAT for one month funded by EUMETSAT. In 2020, a combined product of gridded inter-calibrated radiances that is based on recalibrated radiances from as many geostationary satellite data as possible.
Tasuku Tabata presented the re-calibrated IR and WV channels onboard historical JMA's geostationary satellites collaborated with EUMETSAT to compare with spatially, temporally, and geometrically collocated data observed by a imager on low earth orbit satellite including ARIS, HIRS/2, and IASI covering whole JMA's historical observation period. He also introduced their own SBAF (Spectral Band Adjustment Factors) using IASI observation radiance data. He showed the results of bias of all historical GEO instruments after LEO merging considering IASI-A as prime reference. Using double difference method, estimating the bias/uncertainties of historical HIRS data against IASI-A data. JMA and EUMETSAT are preparing comparison papers.
Masaya Takahashi presented the benefits of GEO-GEO comparison and RGB composites. First he introduced the key outcomes of RGB workshop regarding calibration, i.e. RGB imagery could be potential user of GSICS products that relies on the L1 data quality with different instruments and channels. He also introduced the need of the common reference channels for the global composite RGB imagery or "seamless" colour among different instruments, and showed the example RGB composites such as air mass, dust and so on. He provided the interpretation of RGB composite requirements: Relative contribution to generate RGBs using multi-GEOs : ΔLcal < ΔLSRF < Δllimb, and thus Logically, sequence of correction should firstly, to align the instruments' (GSICS) calibration to that of the reference instrument, secondly, applying the spectral band adjustment factor, and finally apply limb correction. But in practice, RGB expert/developer might want to do the limb correction first, then see what discontinuities are left before going into more detail.
Hyeji Yang presented the results of inter-Comparison between COMS/MI and Himawari-8/AHI. She showed that GEO-GEO direct comparison can be used for inter-comparison with high temporal resolution to investigate seasonal variation and diurnal variation.