1. The Global Space-based Inter-Calibration System
Mitch Goldberg, NOAA/NESDIS
GSICS Executive Panel chair
NOAA/NESDIS

2. ECMWF Meeting, Reading UK
June 22, 2001
GSICS Mission
To provide sustained calibration and validation of satellite observations
To intercalibrate critical components of the global observing system to climate quality benchmark observations and/or reference sites
To provide corrected observations and/or correction algorithms to the user community for current and historical data 2
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3. ECMWF Meeting, Reading UK
June 22, 2001
Or in technical terms:
Quantify the differences – magnitude and uncertainty
Correct the differences – physical basis and empirical removal
Diagnose the differences – root cause analysis
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4. SCOPE-CM to maximize data usage Sustained and Coordinated Processing of Environmental Satellite Data
Users
Satellites & sensors
Satellite data
Essential Climate products
GOS
GSICS
Consistent Calibrated data sets
SCOPE-CM
Regional/Specialized Satellite Centres
Address the requirements of GCOS in a cost-effective, coordinated manner, capitalising upon the existing expertise and infrastructures.
Continuous and sustained provision of high-quality ECVs
GSICS enables the generation of Fundamental Climate Data records and provides the basis for sustained climate monitoring and the generation of ECV satellite products. 4

5. Motivation
Demanding applications require well calibrated and intercalibrated measurements
Climate Data Records
Radiance Assimilation in Numerical Weather Prediction
Data Fusion
Growing Global Observing System (GOS)
Intercalibration of instruments achieves comparability of measurements from different instruments 5 5

6. GSICS Official Members
ECMWF Meeting, Reading UK
GSICS Official Members
June 22, 2001
NOAA
NIST
NASA
EUMETSAT
CNES
CMA
JMA
KMA
WMO
ISRO
IMD
JAXA
USGS
Roshydromet
ESA (observer)
CEOS Precipitation Constellation is working with GSICS via
GPM X-Cal Working Group.
GSICS current focus is on the intercalibration of operational satellites,
and makes use of key research instruments such as AIRS and MODIS
as reference instruments for the operational instruments 6
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7. Space-Based component of the Global Observing System (GOS)7
Intercalibration of instruments achieves comparability of measurements from different instruments 7

8. Calibration is Critical for Climate Change Detection
Before intercalibraion
After intercalibration
Trend of global oceanic total precipitable water decreases from 0.54 mm/decade to 0.34 mm/decade after intercalibrations! Calibration uncertainties translate to uncertainties in climate change detection 8 8 8

9. Building Blocks for Satellite Intercalibration
Collocation
Determination and distribution of locations for simultaneous observations by different sensors (space-based and in-situ)
Collocation with benchmark measurements
Data collection
Archive, metadata - easily accessible
Coordinated operational data analyses
Processing centers for assembling collocated data
Expert teams
Assessments
communication including recommendations
Vicarious coefficient updates for “drifting” sensors

10. Other key building blocks for accurate measurements and intercalibration
Extensive pre-launch characterization of all instruments traceable to SI standards
Benchmark instruments in space with appropriate accuracy, spectral coverage and resolution to act as a standard for inter-calibration
Independent observations (calibration/validation sites – ground based, aircraft)

11. GSICS organization Organizations contributing to GSICS:
CMA, CNES, EUMETSAT, ISRO, JAXA, JMA, KMA, NASA, NIST, NOAA, WMO
Overseen by GSICS Executive Panel
Assisted by Research Working Group
and Data management Working Group
GSICS activities rely on:
GSICS Coordination Centre (GCC)
operated by NOAA/NESDIS
Processing & Research Centres (GPRC)
operated by each satellite operator
Calibration Support Segments (CSS)
including field sites and laboratories
GSICS as an element of the space-based component of the Global Observing System
GSICS activities rely on a GSICS Coordination Centre (GCC) operated by NOAA/NESDIS, several GSICS Processing and Research Centres (GPRC) operated by each satellite operator, and will benefit of Calibration Support Segments including field sites and laboratories.
Activities are overseen by a GSICS Executive Panel assisted by a Research Working Group and a Data management Working Group.
Coordination Center
Calibration Support Segments (reference sites, benchmark measurements, aircraft, model simulations)
Regional Processing Research Centers at Operational Space
Agencies

12. ECMWF Meeting, Reading UK
June 22, 2001
Current focus of GSICS
Interagency collaboration on algorithms (GRWG) and data exchange and formats(GDWG)
Product acceptance and documentation requirements, metadata standards, data formats, website standards
Routine intercalibration (monitor and correct) of all operational GEO Infrared imagers using IASI and AIRS
MODIS and Deep Convective Clouds for visible channels
Intercalibration of LEO instruments
HIRS, SSMI, AMSU, MHS, AVHRR, AIRS, IASI, FY3,
GOME-2, OMI, SBUV
Traceability
Campaigns
Key collocation datasets
Requirements for pre-launch calibration
Root causes and corrections 12 12
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13. First GSICS Guideline document
Best Practice Guidelines for Pre-Launch Characterization and Calibration of Instruments for Passive Optical Remote Sensing
Report to GSICS Executive Panel
R.U. Datla, J.P. Rice, K. Lykke and B.C. Johnson (NIST)
J.J. Butler and X. Xiong (NASA)
September 2009

14. Engage the User Community
Satellite Community – generation of CDRs
New WMO Space Programme SCOPE-CM
ISCCP - Blended geo & leo cloud information
National programs - SDS, SAFs,
Satellite Community - NWP direct radiance assimilation
Reanalysis Community
Next ECMWF reanalysis –
GSICS first major deliverable: Correction Coefficients for all GEO IR using IASI/AIRS as reference from 2003 – 2010+
Satellite Acquisition Programs
Prelaunch instrument characterization guidelines
Cal/Val Plans
Request for new products:
GEO solar channels, LEO microwave instruments

15. Status of GEO-LEO Inter-Calibration
AIRS
IASI
Jan/07
Jan/08
Jan/09
Jan/10
current
GOES-11
GOES-12
GOES-13
Jun/07
Aug/08
Meteosat-9
Meteosat-7
MTSAT-1R
FY-2C
FY-2D
Near-real time monitoring and correction for six operational GEO with baseline algorithm
GSICS Executive Panel Meeting
Geneva, 29 April 2010

16. ECMWF Meeting, Reading UK
June 22, 2001
First international coordinated GSICS project is the intercalibration
of geostationary infrared channels with IASI and AIRS
Ch6
Ch4
Ch3
Ch2
IASI
AIRS
Web Accessible 16 16
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17. ECMWF Meeting, Reading UK
GSICS Correction Algorithm for Geostationary Infrared Imagers
GSICS will provide correction coefficients for all GEOs
from 2003 (beginning of AIRS record) to present
ECMWF Meeting, Reading UK
June 22, 2001
The first major deliverable to the user community is the GSICS correction algorithm for geostationary satellites.
The user applies the correction to the original data using GSICS provided software and coefficients.
The correction adjusts the GOES data to be consistent with IASI and AIRS.
The figures to the left show the difference between observed and calculated brightness temperatures (from NCEP analysis) before and after correction
The bias is reduced from 3 K to nearly zero.
Before 3K Bias
After: ~ 0K Bias 17
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18. IMPACT on Cloud Coverage Classification MSG March 2009
Before GSICS correction
After GSICS correction

19. GOES Sounder Visible band
Low cloud coverage

20. GOES Sounder Longwave Infrared
High clouds embedded in this low level cloud bank
The red circle is included for two reasons. First, the Schreiner-GSICS version tends to be more "smooth" less high clouds embedded in this low level cloud bank. As will be noted in the second circle, this tends to be one of the strengths of the GSICS Bias Coefficients over the "Simple Bias Correction" and the "Dynamic Bias Correction" methods. One curiosity in the red circle region is the large "donut hole" in the northern region of the circle for the "GSICS". None of the other two GOES-15 derived products demonstrate this "hole", and the LWW and VIS show no obvious reason for the hole either.
The white circle in large part also demonstrates the "smooth" nature of the GOES Sounder Cloud Product using the "GSICS" compared to the other two GOES-15 Sounder derived Products. Yet the "Schreiner-GSICS" still keeps the lone high cloud in the south-southwestern sector of the white circle. This "high cloud" is also indicated in the LWW image.

21. GOES Sounder Cloud-top pressure
Fairly noisy higher cloud pixels
GSICS seems to improve (less noise) upon the simple bias correction method for this case, although the masks seems to be adversely affected.

22. GOES Sounder Cloud-top pressure
More uniform cloud pixels

23. GOES Sounder Cloud-top pressure
Fairly noisy higher cloud pixels and missing clouds
Dynamic bias correction is the current NOAA NESDIS version.
GSICS seems to improve (less noise) upon the dynamic bias correction method for this case.

24. GOES Sounder Cloud-top pressure
More uniform cloud pixels and more low cloud

25. Impacts of GSICS Correction for SEVIRI on GFS Forecast
MSG SEVIRI CSR with and without GSICS bias correction
500 mb Anomaly Correlation fover NH

26. GSICS Product Portfolio
For Operational Meteorological Satellites
− Geostationary – IR & Solar
− LEO – IR, Solar, UV, and Microwave – Conical & Cross-track Scanners
− Current Operational & Historic Instruments
− In near real-time and re-analysis modes
GSICS Bias Monitoring
− Routine comparisons of satellite radiances against reference
GSICS Correction
− Function to correct issued radiances
− For consistent calibration with reference
GSICS Diagnosis
− Recommendations to modify practices
− Design and Operation of future satellite instruments

27. GSICS Procedure for Product Acceptance
Products progress from
Demonstration Mode
Through
Pre-Operational Mode To
Operational Mode
By a series of reviews
Over period of ~1.5yr
Subject to meeting
acceptance criteria

28. GSICS Product Acceptance Documentation
Product Algorithm Theoretical Basis Documentation (ATBD)
Discussion of physical principles supporting the product
Software Document
Algorithm flowchart
including data I/O, logic and software module descriptions
Software that meets GSICS standards
On coding, I/O, filename, and documentation (TBD)
Software verification results
Version Control Plan
- Describes process of performing software/model/measurement updates and archive

29. Example of GSICS Bias Monitoring
From CMA: Time Series of FY2D-IASI Standard Biases [K]

30. Example of GSICS Bias Monitoring
From JMA: Time Series of MTSAT-1R-IASI/AIRS Standard Biases [K]

31. Example of GSICS Bias Monitoring
From EUMETSAT: Time Series of Meteosat9-IASI Standard Biases [K]

32. Example of GSICS Bias Monitoring
From NOAA: Time Series of GOES12-AIRS Standard Biases [K]

33. GCC GEO-LEO Baseline Algorithm Implementation
GOES-11/-12, FY-2C, MET-7/-9, and MTSAT-1R with IASI and AIRS
The Baseline Tb bias results computed at the GCC and EUMETSAT for Meteosat-9 are comparable 
GCC uses AIRS and IASI to monitor performance of the two instruments and for diurnal corrections due to solar contamination prone to 3-axis stabilized systems
Baseline algorithm for all GEOs provides confidence of GPRC implementation
Reprocessing of GSICS corrections for all GEOs to 2003 (AIRS) is underway at NOAA/CIMSS.

34. GPM affiliation with GSICS
ECMWF Meeting, Reading UK
June 22, 2001
GPM affiliation with GSICS
Research working group
- Consensus algorithms
Data working group
- Formats, Servers
GSICS Executive Panel
GRWG
GDWG
GCC
CSS
GPRC
Calibration Support
Segments
Coordination Center
Regional Processing Research
Centers at Satellite Agencies
GPM X-Cal
Working Group
CSS
GPRC
CSS
GPRC
GPM X-cal:
Plan to sustain X-cal in future
Similar Structure to GSICS
Interested in using GSICS product acceptance procedure
Precipitation Processing
System at Goddard
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35. GSICS Interface to SCOPE-CM - Outline
Sustained & Coordinated Processing of Environmental satellite data for Climate Monitoring (SCOPE-CM)
WMO Initiative based on activities of existing initiatives (GOS, GCOS and GSICS)
Provides international cooperation and coordination framework
To generate multi-mission and global satellite climate data records (FCDRs & TCDRs)
Serve users and other organisations (e.g. WMO Regional Climate Centres RCC, National Weather Services)
=> The way toward operational production of high quality ECVs on a global scale
Aside – as an example of how GSICS can fit into the scheme of things.

36. GSICS Outcome
Coordinated international intersatellite calibration program
Exchange of critical datasets for cal/val
Best practices/requirements for monitoring observing system performance
Best practices/requirements for prelaunch characterisation (with CEOS WGCV)
Establish requirements for cal/val (with CEOS WGCV)
Advocate for benchmark systems
Quarterly reports of observing system performance and recommended solutions
Improved sensor characterisation
High quality radiances for NWP & Climate

37. Summary GSICS is Global Space-based Inter-Calibration System!
Focuses on Level 1 data => FCDR
GSICS does not (generally) re-calibrate archives of data
But provides products to correct calibration of real-time and archive data to be consistent with reference instruments
Also provides tools to monitor biases in near real-time
To date, GSICS have concentrated on current GEO imagers
Developed Procedure for Product Acceptance
Thorough documentation with traceability
May be applied to 3rd party products
Need to ensure consistency between products
For different instruments – contemporary and historic

38. BAMS April 2011

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