1. SBAF requirements for GEO-GEO comparisons
Na XU
National Satellite Meteorological Center(NSMC), CMA
2019 GSICS Annual Meeting, Frascati, Italy,
04-08, March, 2019
propose

2. Why is there a requirement?
GEO Satellites have the indispensable roles in their dominant regions.
GEO-GEO intercalibration for longterm calibration mornitoring
GEO-ring F(C)DR exploitation for climate research
Rob Roebeling,et al., GSICS annual meeting,2019

3. Example of GEO-Ring FY2E/FY2D/MSG
The radiance obervations show clearly gap in WV bands due to SRF difference;
SBAF is nessisary for GEO-GEO comparison
IR Window (10.8μm)
MSG
FY-2 WV
neglect
MSG
FY-2

4. How important is the SBAF?
Observation difference due to SRF inconsistency is evaluated using a large variety of IASI observations
Observation difference comparing to FY-2E due to SRF inconsistency
GEO SRFs Comparison
The SRFs of FY-2 series are broader than others, and contains more absorption. Radiometric observation of IR window band (10.8μm) is not sensitive to SRF. The mean differences between different GEO senors are less than 0.5K.

5. SBAF calculation and radiance adjust results
FY2D vs FY2E
SBAF calculation and radiance adjust results
The radiance is nomalized to FY-2E's SRF
FY2F vs FY2E
MTSAT2 vs FY2E
quadratic
GOES15 vs FY2E
MSG2 vs FY2E

6. Observation difference comparing to FY-2E due to SRF inconsistency
FY2D vs FY2E
More sensitive to SRF than 10.8μm. not a ideal linear or quatratic relationship, SBA results have big uncertianty
FY2F vs FY2E
GEO SRFs Comparison
MTSAT2 vs FY2E
Observation difference comparing to FY-2E due to SRF inconsistency
GOES15 vs FY2E
MSG2 vs FY2E

7. https://satcorps.larc.nasa.gov/

8. Observation difference comparing to FY-2E due to SRF inconsistencyWV
FY2D vs FY2E
There are large SRF differences and lead to significant obvervation differences in WV bands. FY-2 observations contain more surface informantion than other GEO sensors.
GEO SRFs Comparison
FY2F vs FY2E
MTSAT2 vs FY2E
Observation difference comparing to FY-2E due to SRF inconsistency
GOES15 vs FY2E
MSG2 vs FY2E

9. https://satcorps.larc.nasa.gov/

10. How to do it ?
What is the best method for GEO SBAF calculation especially for WV? As GEO IR bands are wider than that of LEO , general SBAF method seems to have non-negligible uncertanty, and it seems not suitable to all situations
Is the spectral harmonisation necesary for FCDR exploitation?