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Search Publications by: B. Carol Johnson (Fed)

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Displaying 26 - 50 of 178

Results of aperture area comparisons for exo-atmospheric total solar irradiance measurements

November 13, 2013
Author(s)
Bettye C. Johnson, Maritoni A. Litorja, Joel B. Fowler, Eric L. Shirley, James J. Butler, Robert A. Barnes
Exo-atmospheric solar irradiance measurements made by the solar irradiance community since 1978 incorporate limiting apertures with diameters measured by a number of metrology laboratories using a variety of techniques. Knowledge of the aperture area is a

Validation of the dissemination of spectral irradiance values using FEL lamps

September 27, 2012
Author(s)
Bettye C. Johnson, Gary D. Graham, Robert D. Saunders, Howard W. Yoon, Eric L. Shirley
Scales of spectral irradiance are disseminated from NIST by assignment of values to FEL-type lamp standards for defined conditions. These lamp standards can be used for absolute calibration of irradiance radiometers, or more typically, be used in

Stray light correction algorithm for multi-spectral hyperspectral spectrographs

June 1, 2012
Author(s)
Michael Feinholz, Stephanie J. Flora, Steven W. Brown, Yuqin Zong, Keith R. Lykke, Mark A. Yarbrough, B. Carol Johnson, D. K. Clark
An algorithm is developed to correct a multi-channel fiber-coupled spectrograph for stray or scattered light within the system. The efficacy of the algorithm is evaluated based on a series of validation measurements of sources with different spectral

The use of filtered photodetectors for radiance measurement

October 31, 2010
Author(s)
Albert C. Parr, B. Carol Johnson
A methodology for using a calibrated filter radiometer to measure and monitor the spectral radiance of calibration sources is described. An example using a calibration sphere used by NIST for its remote sensing program is presented.

An example crossover experiment for testing new vicarious calibration techniques for satellite ocean color radiometry

October 1, 2010
Author(s)
Kenneth Voss, Scott McLean, Stephanie J. Flora, Michael Feinholz, Mark A. Yarbrough, Charles Trees, Mike Twardowski, Dennis Clark, Marlon Lewis, B. Carol Johnson
Vicarious calibration of ocean color satellites involves accurate surface measurements of water-leaving radiance to update and improve the system calibration of ocean color satellite sensors. An experiment was performed to compare a free-fall technique

Characterization of Two Spectrmeters in Support of the Landsat Data Continuity Mission

August 27, 2010
Author(s)
Bettye C. Johnson, Robert D. Saunders, Zhigang Li, Abra Fein, Lawrence Ong, Milton Hom, Robert Barnes, B L. Markham
The Landsat Data Continuity Mission (LDCM) project at the National Aeronautics and Space Administration (NASA)Goddard Space Flight Center (GSFC) is supervising the manufacture and calibration of the Operational Land Imager (OLI) satellite instrument by

Best Practice Guidelines for Pre-Launch Characterization and Calibration of Instruments for Passive Optical Remote Sensing

November 1, 2009
Author(s)
Raju V. Datla, Joseph P. Rice, Keith R. Lykke, Bettye C. Johnson, James J. Butler, Xiaoxiong Xiong
The pre-launch characterization and calibration of remote sensing instruments should be planned and carried out in conjunction with their design and development to meet the mission requirements. In the case of infrared instruments, the onboard calibrators

Sources of Differences in On-Orbit Total Solar Irradiance Measurements

July 13, 2009
Author(s)
James J. Butler, R Barnes, B. Carol Johnson, Joseph P. Rice, Eric L. Shirley
There is a 5 W/m2 difference between current on-orbit Total Solar Irradiance (TSI) measurements. On 18-20 July 2005, a workshop was held at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland that focused on understanding

Stray Light Correction of the Marine Optical System

January 1, 2009
Author(s)
M Feinholz, S Flora, M Yarbrough, Keith R. Lykke, Steven W. Brown, B. Carol Johnson, Dennis Clark
The Marine Optical System is a spectrograph-based sensor used in the Marine Optical Buoy for the vicarious calibration of ocean color satellite sensors. It is also deployed from ships in instruments used to develop bio-optical algorithms that relate the

Downwelling Surface Spectral Irradiance Measurements with the Marine Optical BuoY

December 31, 2008
Author(s)
Bettye C. Johnson, M Feinholz, S Flora, M Yarbrough, Terrance Houlihan, D Peters, Dennis Clark
The Marine Optical BuoY (MOBY), off the coast of Lanai, Hawaii, has made in situ, in-water up-welling spectral radiance and downwelling surface spectral irradiance measurements since July 1997. The MOBY observatory concept was developed and implemented

The Marine Optical BuoY (MOBY) Radiometric Calibration and Uncertainty Budget for Ocean Color Satellite Sensor Vicarious Calibration

December 31, 2008
Author(s)
M Feinholz, B. Carol Johnson, Steven W. Brown, S Flora, M Yarbrough, Terrance Houlihan, D Peters, Yong S. Kim, J Mueller, Dennis Clark
For the past decade, the Marine Optical Buoy (MOBY), an autonomous radiometric buoy stationed in the waters off Lanai, Hawaii, has been the primary in-water oceanic observatory for the vicarious calibration of the U. S. satellite ocean color sensors

Intercomparisions of Reflectance Measurements

October 16, 2008
Author(s)
P Y. Barnes, B. Carol Johnson, James J. Butler, C J. Bruegge, S F. Biggar, P R. Spyak, M M. Pavlov, E A. Early
A comparison of spectral diffuse reflectance between different national standards laboratories is being planned under the direction of the Comit* Consultatif de Photom*trie et Radiom*trie (CCPR). A similar comparison of bi-directional reflectance

Metrology for Remote Sensing Radiometry

October 16, 2008
Author(s)
B. Carol Johnson, Steven W. Brown, Joseph P. Rice
Metrology, the science of measurement, is discussed in terms of measurements of radiant flux and associated quantities. Radiometric measurements are naturally remote, that is, they are non-contact. A broad application is Earth science, as global

Overview of Radiation Thermometry

October 16, 2008
Author(s)
B. Carol Johnson
Researchers in the Optical Technology Division utilize measurements of radiant flux to determine temperature. This includes the dissemination of the ITS-90 above 961.78 degrees C using spectral radiance ratios (optical pyrometry) and absolute measurements

Calibration of a Radiance Standard for the NPP/OMPS Instrument

October 9, 2008
Author(s)
Bettye C. Johnson, James J. Butler, Scott J. Janz, Robert D. Saunders, John W. Cooper, Matthew G. Kowalewski, R Barnes
In June 2007, a spherical integrating source was calibrated in the National Aeronautics and Space Administration(NASA) Goddard Space Flight Center’s (GSFC) Calibration Facility as part of the prelaunch characterization program for the NPOESS Preparatory

Measurement science for climate remote sensing

August 20, 2008
Author(s)
Gerald T. Fraser, Steven W. Brown, Raju V. Datla, Bettye C. Johnson, Keith R. Lykke, Joseph P. Rice
The Earth s climate is very complex and highly variable, making it difficult to measure and model small changes that occur over decadal and longer time scales. The resulting uncertainties in measurement and modeling underlie the longterm debate over the

The Marine Optical BuoY (MOBY) Radiometric Calibration and Uncertainty Budget for Ocean Color Satellite Sensor Vicarious Calibration

November 1, 2007
Author(s)
Steven W. Brown, S Flora, M Feinholz, M Yarbrough, Terrance Houlihan, D Peters, Yong S. Kim, J Mueller, Bettye C. Johnson, Dennis Clark
For the past decade, the Marine Optical Buoy (MOBY), an autonomous radiometric buoy stationed in the waters off Lanai, Hawaii, has been the primary in-water oceanic observatory for the vicarious calibration of U. S. satellite ocean color sensors, including

Results in Coastal Waters With High Resolution In Situ Spectral Radiometry: The Marine Optical System ROV

October 5, 2007
Author(s)
M Yarbrough, M Feinholz, S Flora, Terrance Houlihan, B. Carol Johnson, Yong S. Kim, Marilyn Y. Murphy, Michael Ondrusek, D K. Clark
The solar normalized water-leaving spectral radiance is a basic ocean color remote-sensing parameter required for the vicarious calibration and bio-optical product development. Determination of normalized water-leaving spectral radiance using in-water

Area Measurements of Apertures for Exo-Atmospheric Solar Irradiance for JPL

September 13, 2007
Author(s)
Maritoni A. Litorja, Bettye C. Johnson, J B. Fowler
A comparison of the area measurements of the limiting apertures used for total solar irradiance measurements in the Active Cavity Radiometer Irradiance Monitor II (ACRIM II) and Active Cavity Radiometer Irradiance Monitor III (ACRIM III) were conducted

Absolute Flux Calibrations of Stars

August 30, 2007
Author(s)
Gerald T. Fraser, Steven W. Brown, Howard W. Yoon, Bettye C. Johnson, Keith R. Lykke
Absolute stellar photometry is based on 1970s terrestrial measurements of the star Vega referenced against the Cu fixed-point blackbody. Significant advances in absolute radiometry have been made in the last 30 years that offer the potential to improve

Simultaneous Measurement of Up-Welling Spectral Radiance Using a Fiber-Coupled CCD Spectrograph

August 26, 2007
Author(s)
M Yarbrough, S Flora, M Feinholz, Terrance Houlihan, Yong S. Kim, Steven W. Brown, B. Carol Johnson, Kenneth Voss, Dennis Clark
Determination of the water-leaving spectral radiance using in-water instrumentation requires measurements of the up-welling spectral radiance (Lu) at several depths. If these measurements are separated in time, changes in the measurement conditions result