NIST Update CEOS WGCV 22

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NIST Update -- CEOS WGCV 22 June 14 17,
2004 Sioux Falls, SD B. Carol Johnson Optical
Technology Division Physics Laboratory National
Institute of Standards and Technology http//p
hysics.nist.gov/Divisions/Div844/div844.html
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Outline

• Status of Core Facilities (See NIST Presentation
  to WGCV-21)
• Accomplishments Interactions in Remote Sensing
  Projects
• UV, Vis, TIR (Gaithersburg)
• microwave (Boulder)

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Advanced Measurement Laboratory (AML)

• Four instrument buildings (two below grade) and
  one clean room building, total 47,480 m2 (511,000
  sq ft)
• Vibration 0.75 to 3 ?m/s
• Temperature 0.25C (0.1C or 0.01C)
• Air Quality Class 1000 (Class 100)
• Humidity 5 (1 )
• Conditioned power, meets IEEE Std. 1100-1992

Thoughtful design wide service alleys between
labs, high lab ceilings, offices on external
walls, wide hallways.
The High Accuracy Cryogenic Radiometer 2 (HACR 2)
instrument, the facility for Spectral Irradiance
and Radiance Responsivity with Uniform Sources
(SIRCUS), and the Aperture Area Facility moved to
the AML buildings in early 2004.
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Absolute Radiometry

• Electrical substitution radiometry
• Optical watt equivalent to electrical watt
• Cryogenic cavities and flux-stabilized lasers
• Reference standard detectorsflux responsivity
• Scale realizations in detector responsivity,
  spectro-radiometry, and photometry

HACR 2 Modular horizontal cavity, windowless
operation Comparisons performed with HACR before
the move to AML
L-1 ACR
HACR 2
L-1 ACR Flexible system for routine calibrations
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SIRCUS
Spectral Irradiance and Radiance Responsivity
with Uniform Sources
Detector based facility for determination of
absolute spectral irradiance or radiance
responsivity of optical sensors Basic technique
Reference detectors calibrated using cryogenic
electrical substitution radiometry laser
illuminated integrating sphere sources for
monochromatic characterization and calibration of
radiometers variety of laser systems provide
tunable coverage UV, visible, near-IR,
IR Low uncertainties 0.1 to 0.2 (k
2) Validation methods absolute determination
of the freezing point of gold and silver
comparisons with the NIST Synchrotron Radiation
User Facility (SURF III) News Pulsed OPO for
200 nm to 1.7 ?m (3.0 ?m with reduced flux),
continued improvements to reference detectors and
IR SIRCUS. Facility operational in AML.
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SIRCUS Applications

• Accomplishments in Remote Sensing
• Robotic Lunar Observatory (ROLO)
• Marine Optical Buoy (MOBY)
• Earth Polychromatic Imaging Camera (EPIC)
• Goddard Space Flight Center Transfer
  Spectroradiometer (GSFC 746/ISIC)
• Sun Photometers (SIMBIOS, AERONET)

• Impacts
• Satellite sensor on-board calibration
  degradation corrections
• Accuracy of ocean color products (e.g. chl a)
• Novel measurements (DSCOVR at L1)
• Accuracy of aircraft validation sensors
• Atmospheric correction procedures

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New Scale Realization Procedure D2 Lamps
D2 lamps calibrated using SURF III BL 3 as a
primary source standard

• 5x reduction in irradiance uncertainty
• Improvements in lamp reproducibility
• Elimination of transfer based on relative
  spectral irradiance calibration using the
  hydrogen arc
• CCPR-K1.b participation (200 to 400 nm)
• Impact UV radiometry, ozone retrievals

D2 Lamp
SURF III Layout
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Novel Sources for Remote Sensing

• Solid-state LED Calibration Sources
• Advantages
• Controllable output 350 nm to gt900 nm
• Higher flux in UV and blue
• Compact, light-weight, low power consumption
• Good temporal stability
• Shock resistant
• Provides a great deal of flexibility in source
  design
• Enables derivation of sources with unique
  spectral distributions.

Target spectrum Source distribution
Radiance
Radiance
Radiance
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New Radiometers for Remote Sensing

• Based on a Bomem MR-154
• Includes 2 blackbodies that hold the radiance
  scale AERI heritage
• Delivered to NIST December 2003
• Radiance scale will be based on NIST LABB
  cryogenic blackbody.
• Radiance scale will be validated by comparison to
  the
• NIST detector-based scale at IR-SIRCUS
• Comparison to underway (WBBB and TXR)

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Validation for NPP/NPOESS (VIIRS) in TIR

• Thermal Infrared Transfer Radiometer (TXR)
• Measures radiance of thermal sources
• 5 ?m and 10 ?m channel
• Ambient or vacuum operation
• Includes blackbody source standard
• Uncertainty lt0.1 K at 300 K (k2)
• Traceable to ITS-90 (temperature standards)

TXRdeployed to LANL (DOE), ITT (NOAA GOES
Imager), Univ Miami (SST), SBRS (DOD and
NPP/NPOESS)

• Impacts
• NIST internal ambient IR scales (water bath and
  oil bath blackbody comparisons)
• Procedure developed to distinguish correct
  temperature and emissivity
• Verified uncertainties of TIR source standards
  and chamber radiometric models at host
  facilities

NPP/NPOESS VIIRS Blackbody Calibration Source
NIST/EOS TXR at SBRS Jan/Feb 2004
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Community Participation
NISTIR 7047 Satellite Instrument Calibration
for Measuring Global Climate Change. Report of
the College Park MD Workshop, November 2002. EOS
Workshop on AM Constellation Cal/Cross-Cal,
Greenbelt, MD, November 2003. Joint ISPRS /
CEOS-WGCV Interim Task Force Report. Draft
report of the Results and Recommendations of an
International Workshop on Radiometric and
Geometric Calibration, Gulfport, MS, December
2003. The Status of NASA Ocean Color Research
Using SeaWiFS, MODIS (Terra and Aqua) and
Implications for NPP/VIIRS, report of Greenbelt,
MD Workshop, February 2004. Review strategic
plans of the U.S. Climate Change Science Program
and the U.S. Climate Change Technology
Program. Participation in upcoming Workshops
Meetings (CALCON, ESA / ESTEC, NASA TSI,
etc.) New Program NOAA GOES-R series of
instruments Cal/Val support
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Recommendations

• Exo-atmospheric solar spectral irradiance
  valuescontinue to promote documentation efforts
  and impact studies
• Spectral responsivity functions (system level at
  operating temperatures over the full
  out-of-band region)
• Artifacts for down-stream characterization
  (programs should produce and archive witness
  samples)
• Elements of Measurement Comparison Activities
• Instrument calibration all radiometers view a
  common stable source
• Instrument characterization repeatability,
  reproducibility, temperature, power cycling,
  etc.
• Radiometric standards Exp. stable radiometers,
  one lamp, various plaques
• Atmospheric correction intercompare results
  using common inputs
• Spectral issues spectral mismatch and product
  algorithms, wavelength calibration, etc.
• Analysis of Comparison Activities Data and
  production of archival publications.

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Acknowledgements

• Numerous Other Collaborators, Including
• Jim Butler, NASA Goddard
• Steve Mango, IPO
• Dennis Clark, NOAA
• Steve Kirkner, NOAA
• Tom Stone, USGS
• Chuck McClain, NASA Goddard

• NIST Optical Technology Division
• Collaborators
• Leaders of the NIST Calibration Effort
• Carol Johnson
• Joe Rice
• Steve Brown
• Other NIST Collaborators
• David Allen
• Raju Datla
• Charles Gibson
• Toni Littorja
• Keith Lykke
• Al Parr (Division Chief)
• Jim Proctor
• Bob Saunders
• Howard Yoon

SeaWiFS