V: Instrument

1
V Instrument Product Calibration / Validation
Alexander P. Trishchenko (Environment Canada)
Fuzhong Weng (NOAA)
on secondment from the Canada Centre for Remote
Sensing, NRCan
2
Outline

• EC PCW CalVal Plan
• Calibration requirements for PCW imager vs GOES-R
  ABI
• Planned instrument calibration approach for PCW
• Inter-calibration with GEO and LEO, participation
  in GSICS
• STAR CalVal Overview
• IJPS Calibration
• GOES/GOES-R
• NPP/JPSS
• Non-NOAA (FY-3/DMSP/NASA/Jason)
• GSICS

3
PCW Imager Vs GOES-R/ABI
B Subgroup Wavelength (microns) S/N, NEDT or NEDR Calibration Accuracy Geometric Accuracy (GA) Dynamic Range
1 VNIR 0.45-0.49 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
2 VNIR 0.59-0.69 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
3 VNIR 0.700-0.718 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
4 VNIR 0.85-0.89 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
5 SWIR 1.04-1.06 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
6 SWIR 1.37-1.39 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
7 SWIR 1.58-1.64 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
8 SWIR 2.22-2.28 PCW 1300 _at_ bright signal level (100 albedo SZA300) ABI 1300 at 100 albedo PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 0-1.15 100 albedo Linearity range (dim to bright) Bright SZA300, 100 albedo Dim SZA800,1 albedo ABI 0-1.15 100 albedo
9 MWIR 3.80-4.00 PCW 0.005 mW/m2/sr/cm-1 ABI 0.004 mW/m2/sr/cm-1 (0.1K_at_300K) PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-410K ABI 4K-400K
10 MWIR 5.77-6.60 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
11 MWIR 6.75-7.15 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
12 MWIR 7.24-7.44 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
13 LWIR 8.30-8.70 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
14 LWIR 9.42-9.80 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
15 LWIR 10.1-10.6 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
16 LWIR 10.8-11.6 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
17 LWIR 11.8-12.8 PCW lt0.15K _at_300K lt0.35K _at_240K ABI 0.1K _at_300K 0.18-0.37K) _at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-335K (4K-300K for Ch.10, 11, gt13mm) ABI 4K-300K (Ch.10-11,14) 4K-330K (Ch.13,15-17) 4K-320K(Ch.12) 4K-305K(Ch.18)
18 LIRCO2 13.0-13.6 PCW lt0.35K_at_300K lt0.5K_at_240K ABI 0.3K_at_300K 0.48K_at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-300K ABI 4K-305K(Ch.18)
19 LIRCO2 13.5-13.8 PCW lt0.35K_at_300K lt0.5K_at_240K ABI 0.3K_at_300K 0.48K_at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-300K ABI 4K-305K(Ch.18)
20 LIRCO2 13.8-14.1 PCW lt0.35K_at_300K lt0.5K_at_240K ABI 0.3K_at_300K 0.48K_at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-300K ABI 4K-305K(Ch.18)
21 LIRCO2 14.1-14.4 PCW lt0.35K_at_300K lt0.5K_at_240K ABI 0.3K_at_300K 0.48K_at_240K PCW Solar bands 5 IR bands 0.5K ABI Solar bands lt4 IR-bands 1K _at_300K PCW (1-s) Absolute GA error lt0.35 of Angular Sampling Distance (ASD) Band-to-band co-registration error lt0.3 ASD ABI (3-s) Absolute navigation errors 21 to 32 mrad depending on sun eclipse Band-to-band co-registration error lt6.4mrad PCW 4K-300K ABI 4K-305K(Ch.18)
Bands in Bold are Priority 1. The remaining bands
are in priority 2 list
4
Calibration for PCW

• Pre-launch characterization
• Some limited capacity exist in Canada (ABB BOMEM,
  COMDEV, CSA DFL)
• Co-operation with NOAA, NASA and NIST would be
  very helpful for pre-launch radiometric,
  geometric and spectral calibration of PCW imager
• In-flight calibration
• Solar, spectralon diffusor(s) frequent in the
  beginning, periodic during regular operations
  (limited by spectralon UV exposure)
• Blackbody, every scene
• Deep space counts (twice per scan)
• Intercalibration between PCW imagers to ensure
  consistency in derived imagery and products
• Lunar calibration co-operation with NOAA and
  NASA would be very helpful
• NOAA bias analysis using comparison with RTM
  results would be very useful

5
Intercalibration with LEO and GEO

• PCW would significantly benefit from
  participation in the Global Space-based
  Inter-Calibration System (GSICS)
• Improved quality of PCW imagery and products
• Consistency between PCW and other satellite data
• PCW can be intercalibrated against polar orbiters
  (LEO) as well as GEO
• The Climate Absolute Radiance and Refractivity
  Observatory (CLARREO) mission led by NASA could
  be of a unique value for absolute radiometric and
  spectral calibration

6
Temporal coverage map for PCW system
( of total time, 100 means 24hrs per day)
VZA lt700 100 coverage gt580N 50 for
tropics Up to 20 for tropical zone below
equator Good opportunity for temporal and
spatial collocation
Trishchenko and Garand, 2010, JTECH, submitted
7
Imagery and Product Cal/Val

• Part of the PCW Meteorological Product
  Application Processing Facility (MAPF) at EC.
• L1 QC
• Calibration monitoring
• Geolocation monitoring
• Operational product verification
• Operational analysis and reporting statistics
• Visual control
• Cal/Val activities could be shared with NOAA
• Science activities
• Focused research in special areas of interest
  products
• Specialized product cal/val projects involving
  joint science teams
• Partnering with CEOS WGCV and GSICS

8
NESDIS/STAR Operational Calibration

• IJPS (NOAA/METOP) Calibration
• TVAC analysis
• Radiometric calibration
• Calibration coefficients LUT and data sets
• Spectral and spatial calibration
• On-orbit verification and Long-term monitoring
• GOES-R Calibration Working Group
• Post-launch checkup
• Vicarious calibration
• NPP/JPSS Calibration
• SDR Code processing and updates
• On-orbit Verification
• Long-term monitoring
• Non-NOAA Instruments (FY-3/DMSP/GPM)
• WMO GSICS Executive Chair and Coordination
  Center

9
The GOES-R Calibration Working Group Led by Dr.
C. Cao

• Verify and ensure well-calibrated,
  well-navigated GOES-R L1b data for the life time
  of the instruments (ABI, GLM, and SWx)
• Ensure Level 1B data quality. Provide technical
  oversight and IVV for
• Radiometric calibration
• Spectral calibration
• Spatial calibration/navigation check
• Independent verification of L1B data

• Evaluate and mitigate instrument performance
  risks (e.g., possible striping, noise,
  cross-talk, RVS, spectral response uncertainty,
  etc)
• Provide technical support to the Flight and
  Ground through PSE

10
The GOES-R Calibration Working Group Expertise

• Prelaunch calibration support (flight segment)
• Test data analysis and instrument performance
  evaluation (bench and thermal vacuum)
• Prelaunch test participation on-site at Rochester
  and Fort Wayne (w/ two CWG representatives)
• SI traceability using NIST state-of-the-art
  technologies such as transfer radiometers (TXR,
  VXR) as well as SIRCUS characterization
• Expertise include advanced degrees in
  opto-electronics, physics, imaging science,
  software engineering, and Earth sciences.
• Advisors from heritage GOES, POES, and NASA EOS
  programs
• Members from NOAA, NASA, NIST, and MIT/LL
• Ground systems
• Calibration support to the operational processing
  system design and development
• Postlaunch capability developments
• On-orbit verification
• Instrument performance evaluation
• Anomaly diagnosis
• Vicarious calibration
• Operational longterm monitoring
• Prototyping for GOES-R using current GOES data
• GSICS collaboration

From Meteorology to Metrology
11
Four Phases of Calibration/Validation

• 1. Pre-Launch (development and IT)
• - CDRL peer review, PDR/CDR
• - Algorithm calibration database development
• verification
• - Data format/content/quality flags
• - Bench/TVAC tests and analysis
• - Trade studies and waivers
• - Validation capability development and
  preparation
• - Prelaunch SI traceability
• 2. Operational check-out (Post-Launch Tests)
• - Engineering tests to ensure specification
  compliance
• - Calibration processing
• - Anomaly analysis
• 3. On-orbit verification (Environmental cal.
  initialization)
• - Instrument characterization
• - Sensor artifact study and correction
• - Algorithm adjustment

12
Spectral Response Function Analysis

• Two sets of pre-launch spectral response
  functions (SRFs) for ABI
• The CIMSS version and the CWG version
• Quantified the differences between them and their
  impacts through spectral analysis using Hyperion
  and IASI spectra
• Working with AWG to assess impact (Walter Wolfe
  Jamie Daniels)

Hyperion Derived (VNIR) Targets
IASI Derived (IR) Targets
13
Spectral Response Function Analysis

• Differences found between the two sets of SRFs
• Solar Bands differences ranged from near 0 to
  approaching 2 TOA reflectance
• IR Bands differences from near 0 to gt1K in
  brightness temperature
• Recommendation users should use a consistent set
  of SRF, until the flight model SRF becomes
  available

VNIR Results
IR Results
14
NIST Activities

• Working with NIST and ITT on the deployment of
  NIST instruments
• VXR Spring 2011
• TXR 2010
• SIRCUS in discussion with ITT
• Thermal Transfer Radiometer (TXR), Visible
  Transfer Radiometer (VXR), and ASD Spectrometer
• Ensure prelaunch SI traceability
• Spectral Irradiance and Radiance Responsivity
• Calibrations using Uniform Sources (SIRCUS)
• Significantly improves solar band spectral
  response
• function characterization/validation
• Straylight characterization
• Capabilities for IR channels are being developed

15
GOES-R Ground System Support

• Defining instrument calibration data sets
• Calibration data files proposed
• Once every two hours one for each instrument
• Example items
• Instrument temperatures
• Calibration event data (e.g., internal target and
  space view counts)
• Calibration data statistics (e.g., instrument
  noise)
• Level 1b landmark data
• Calibration data will go into GAS (GOES-R Access
  Subsystem, 7day storage), and CLASS (for
  long-term)
• Collaborating with NSOF calibration specialists
  to ensure operational monitoring of
• Calibration-related instrument engineering and
  science data
• L0-to-L1b data processing parameters
• Work in process, not all instruments have passed
  CDR

16
Global Space-based Inter-Calibration System

• What is GSICS?
• Global Space-based Inter-Calibration System
• Initiative of CGMS and WMO
• An effort to produce consistent, well-calibrated
  data from the international constellation of
  operational meteorological satellites
• What are the basic strategies of GSICS?
• Best practices/requirements for prelaunch
  characterisation (with CEOS WGCV)
• Improve on-orbit calibration by developing an
  integrated inter-calibration system
• Initially by LEO-GEO Inter-satellite/inter-sensor
  calibration
• This will allow us to
• Improve consistency between instruments
• Produce less bias in Level 1 and 2 products
• Retrospectively re-calibrate archive data
• Better specify future instruments

17
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
Coordination Center
Calibration Support Segments (reference sites,
benchmark measurements, aircraft, model
simulations)
Regional Processing Research Centers at
Operational Space Agencies
18
Applications of GSICS

• Quantify the differences magnitude and
  uncertainty
• Remove the differences empirical or physical
• Understand the differences root cause analysis
  and correction/prevention

19
GOES Imager 13.3 µm Channel SRF

• GOES-13 PLT found Imager Band 6 cold bias of -2.4
  K
• Original proposal of a -4.7 cm-1 shift of SRF
• Instrument vendor revised SRF, effectively
  shifted -1 cm-1
• NOAA implemented additional -2.1 cm-1 shift,
  eliminated bias and its dependence on scene
  temperature (not shown)

GOES-13 Imager Band 6 spectral response
functions, with (green) and without (blue) a -4.7
cm-1 shift, superimposed on spectral radiance for
the U. S. Standard Atmosphere (red).
GOES-13 Imager Band 6 spectral response
functions, original (blue) and revised (red),
superimposed on AIRS spectral radiance for the U.
S. Standard Atmosphere (black).
GOES-13 Imager Band 6 radiance difference (in
terms of brightness temperature) from AIRS (blue)
and IASI (red), two well calibrated hyperspectral
instrument used as reference for GSICS.
20
GSICS Monitoring and Correction
21
Impact of GSICS Correction on GOES-12 Imager
radiance
Compared to CRTM, GOES-12 Imager Channel 6 bias
was reduced from -2.55K before GSICS correction
to -0.11K after
T. Zhu, F. Weng
22
Impact of GSICS Correction for GOES-12 Imager
radiance on GFS forecast
GOES-12 imager with and without GSICS bias
correction Anomaly Correlation for 500 mb height
over tropics (left) and NH (right)
T. Zhu, F. Weng
23
Impact of GSICS Correction for SEVIRI radiance on
GFS forecast
MSG SEVIRI CSR with and without GSICS bias
correction Anomaly Correlation for 500 mb height
over tropics (left) and NH (right)
T. Zhu, F. Weng
24
Double Difference Technique A Robust Way for
Estimating Sensor to Sensor biases

• It reduces the impact related to temporal
  difference when two instruments have distinct
  orbits
• It reduces the errors related to forward models
  and from forecast models
• It works in the region where the forward model
  has the same error characteristics

• Assumptions
• The same temporal difference from observations
  and simulations
• Negligible forward model biases for two
  instruments

25
SSMIS TDR Anomalies

• ( Observation Simulation )

54.4 GHz V
55.5 GHz V
26
Double Difference Technique (DDT)
27
Summary

• PCW calibration can be leveraged from NOAA GOES-R
  calibration components
• GSICS baseline algorithms can be refined for PCW
  applications