1. Na XU Xiuqing HU Lin CHEN Ling SUN NSMC CMA 2014-3-27
Long-term monitoring of FY-2 and FY-3 IR calibration using GSICS products
Na XU Xiuqing HU Lin CHEN Ling SUN
NSMC CMA

2. Outline
Current Status
IR Bias monitoring of FY-2 VISSR
IR Bias monitoring and correction of FY-3A&B MERSI and VIRR
GSICS support to On-orbit test of FY-3C
Future Prospects

3. Current Status of CMA GSICS Products
Mon
Ref
Graphic Products##
Collocation & Correction Products**
FY2D&E&F/ VISSR
Metop-A/IASI (Op.)
AQUA/AIRS (Op.)
NPP/CrIS (Developing)
Ocean buoy RTM (Plan)
Daily Regression (RAD~RAD and TBB~TBB)
Monthly Scatter of TBB Bias
Time Sequence of TBB Bias
Collocation Samples
Intercalibration Coefficients
NRTC and RAC in txt (Plan to generate the GSICS standard format)
FY3A&B&C/MERSI
&VIRR
NPP/CrIS (Demo)
Monthly Regression (RAD~RAD and TBB~TBB)
AQUA&TERRA MODIS (Demo)
NPP/VIIRS (Demo)
GOME (Developing)
Monthly Regression (REF~REF)
Monthly Scatter of REF Bias
Time Sequence of REF Bias
Projected Image
NRTC and RAC
Stable Targets Tracking (Developing)
Time Sequence of Response
Degradation Rates
TEB
RSB
## : see
** : Only Internal Shared currently.

4. IR Calibration Bias of FY-2 VISSR
FY-2 vs IASI+AIRS
Significant progresses were made in FY-2 operational calibration (Changed to GSICS in 2012)
Eclipse Phase
GSICS
Operational calibration of FY-2D/2E was upgraded using GSICS inter-calibration algorithm in and separately.
The calibration biases were sharply decreased, and reduced to about eclipse period.
GSICS
Time series of TBB biases for IR1~3 channels vs AQUA/AIRS
reference scenes (290 K for IR1 and IR2, 250 K for IR3).

5. IR Calibration Bias of FY-2 VISSR
GSICS
CIBLE
2012
2013
Significant progresses were made in FY-2 operational calibration (Changed to CIBLE in 2013)
IR biases of the New operational calibration ：
Seasonal variation: FY-2D biases, IR1 ( 1~2K), IR2 ( 2~3K), IR3(0.5~1K)；FY-2E biases , IR1 (-1~-0.5K), IR2 ( 1~2K), IR3(-3~-2K)；FY-2F biases , IR1 ( 1~2K), IR2 ( 2~3K), IR3(0.5~1K)；
Inconsistent and systematic bias between IR bands [（VISSR-IASI) _IR1- （VISSR-IASI) _IR2]
Time series of TBB biases for IR1~3 channels vs IASI and AIRS
reference scenes K for IR1 and 250 K for IR3).
Op. Cal Upgrade date：FY2D ; FY-2E
CIBLE (Calibration of Inner Blackbody corrected by Lunar Emission )

6. IR Calibration Bias of FY-3
Based on LEO-LEO SNO intercalibration method, IR calibration biases of FY-3A&B VIRR and MERSI are assessed
Spatial distributions of cross points
FY-3B~METOP-A
Temporal distributions of cross points
Collocation criteria:
Observation time difference < 300s
Spacial Distance <1km
geometry difference |cos(FY_zen)/cos(REF_zen)-1| < 5%
Environment uniformity check RSTD (FY3 in ENV_BOX) < 0.005

7. IR Calibration Bias of FY-3A&B VIRR
FY-3A&B/VIRR vs METOP-A/IASI
FY3A/VIRR
SRF
FY3A/VIRR
Scene Temp-dependence and Seasonal variation
FY3B/VIRR
FY3B/VIRR
FY-3B/VIRR Measurements are more consistent with IASI
Time series of VIRR Monthly Mean Bias versus IASI
BT comparison (Right) as well as their observation differences (VIRR-IASI) in Aug. 2012

8. Improvement to nonlinear correction of FY-3A VIRR
Channel 4
BT biases scatter of FY-3A/VIRR using nonlinear correction coefficients before and after improvement
Channel 5
Before
After
Normalized PDFs of FY-3A/VIRR BT biases in different months using different nonlinear correction coefficients

9. IR Calibration Bias of FY-3A MERSI
FY3A/MERSI vs METOP-A/IASI
Measurements from FY-3A/MERSI are warmer than that from IASI. Annual mean bias is 3.17 ±0.35K in 2012,which is consistent with the assessment from CRCS synchronous in situ measurements.
The BT biases show seasonal variation.
BT comparison (left) as well as their observation differences (VIRR-IASI) in Aug. 2012
SRF
Time series of VIRR Monthly Mean Bias versus IASI

10. FY-3C On-orbit Test—IR calibration assessment
FY-3C/MERSI vs METOP-A/IASI
Mean Bias
0.57±0.29K
FY-3C/VIRR vs METOP-A/IASI
Mean Bias
CH4：-1.01±0.47K
CH5：-0.95±0.38K
Dec. 2013

11. FY-3C On-orbit Test—IR calibration improvement
Onboard BB Radiance is recalculated using PRT physical temperature
VIRR vs IASI
Channel 4
-0.47K
VIRR vs MODIS
-0.44K

12. FY-3C On-orbit Test—IR calibration improvement
Onboard BB Radiance is recalculated using PRT physical temperature
VIRR vs IASI
Channel 5
-0.40K
VIRR vs MODIS
-0.41K

13. FY-3C On-orbit Test—VNIR calibration coefficients
CH12
CH14
CH15
Differences between FY-3C/MERSI and TERRA/MODIS measurements due to spectral mismatches simulated using GOME-2
<2%
CH12：~6%; CH14：~8%;CH15：~20%

14. FY-3C On-orbit Test—VNIR calibration coefficients
Regression between collocated FY-3C/MERSI DN and TERRA/MODIS reflectance（ ）

15. FY-3C On-orbit Test—VNIR calibration coefficients
Nonlinearity or inconsistency using various references
StableTargets
Intercalibration of FY-3C/MERSI based on various targets（ ）
Stable Targets: MultiSite (Dunhuang , Libya1, Libya4, Arabia2, Lanai), DCC, Moon

16. Chinese Meteorological Satellite: FengYun Series
Polar System
Geostationary System FY | 2A 2B 2C 2D 2E 2F … 2H FY | 1A 1B 1C 1D
First Generation
First Generation FY | 3A 3B 3C 3D … 3F
Based on the current generation of polar and geostationary systems, since 1990s, we began to develop the next generation both for polar and Geo, which called FY3 in polar series, and FY4 in Geo series. FY | 4A 4B 4C … 4F
Second Generation
Second Generation 16

17. Future Prospects — CMA GSICS Products
FY-2
FY-4
FY-3
REF IASI,CrIS,VIIRS,GOME…
GEO-LEO-GEO
GEO-GEO
LEO-GEO
LEO-GEO-LEO
Inter-Platform
LEO-LEO
VNIR: Tracking and RayMatch using stable targets（Desert, Snow, DCC, Moon…）

18. Thanks for your attention!