GRWG/GDWG Web Meeting 2011-07-26

GSICS Web Meeting on GSICS calibration result of FY-2 IR bands and Correction Policy

Agenda

1 Xiuqing Hu (CMA) - FY-2 IR GSICS Correction policy

2 Na Xu (CMA) – FY-2D/E GSICS calibration results from CMA’s GPRC

3 Fangfang Yu (NOAA) – FY-2C/D baseline

4 Zhang Yong (CMA) - Re-calibration of FY-2 data archived at CIMSS/SSEC & onboard blackbody calibration of FY-2 based on GSICS

5 Tim Hewison (EUMETSAT) - Accounting for midnight calibration problem in GEO IR channels

6 Fangfang Yu (NOAA) - GSICS correction of this midnight calibration errors

7 Arata Okuyama (JMA) - MTSAT-2 midnight calibration error

Attendees

Guest Chair: Ling Sun (CMA)

CMA: Ling Sun, Na Xu, Xiuqing ("Scott") Hu, Lin Chen, Yong Zhang, Tao Zhang

EUMETSAT: Marianne Koenig, Tim Hewison

JMA: Arata Okuyama, Kenji Date, Hiroaki Tsuchiyama, Ryuichoro Nakayama, Yuki Kosaka, Yoshihiko Tahara

KMA: Dohyeong Kim

NOAA: Fangfang Yu, Likun Wang, Bob Iacovazzi

Summary

In the 1st part of this meeting, FY-2 IR bands GSICS correction policy and results were discussed. Scott gave an overview of GSICS work at CMA. FY-2D/E operational calibration monitoring test using GSICS IR calibration have been carried out, and GSICS two weekly reports have been produced since May 2011. CMA would prefer to provid new LUT from GSICS as the GSICS correction output. Dr Xu descibed the recent FY-2D/E GSICS calibration results at CMA’s GPRC. Bright temperatures calculated from two independent intercalibrations (IASI and AIRS) agreeed to each other with mean bias less than 0.5K. The accuracy of GSICS intercalibration for FY-2X infrared channels was about 2K. Fangfang introduced the FY-2C/D work at NOAA. It was indicated that some filtering algorithm should be taken to remove the monogenous collocated outliers. FY-2C/D had strong seasonal calibration variations, but diurnal variation seemed to be relatively small. Dr. Zhang reported the progress of onboard blackbody calibration based on GSICS. The fore-optics radiance could be simulated with a linear model constructed from GSICS calibration results and telemetry data. It was noted that a ten-day step of history data would be more suitable for the simulation model.

Outcome

CMA would prefer to issue a "GSICS Calibration" for the IR channels of FY-2X imagers. It was agreed that these products do not have to follow exactly the same format as other GSICS Correction products. However, it may be possible to follow JMA’s example of distributing a calibration Look Up Table with the GSICS Correction coefficients in netCDF format – even if the GSICS Correction is relative to a nominal calibration, using offset=0 and slope=1.

Action: Fangfang Yu to distribute prilimary results of analysis of diurnal cycle in the IR channels of Meteosat and MTSAT imagers to GSICS for review.

Action: Tim Hewison to attend to schedule follow-on web meeting in the week 8-12 August to agree approach for accounting for diurnal variations in GEO calibration in time for 2011 GSICS Users' Workshop.