Radiometric Measurement Comparisons at NASA's Goddard Space Flight Center: Part II. Irradiance Lamp Comparisons and the NIST Sphere Source
James J. Butler, B. Carol Johnson, R Barnes
The National Aeronautics and Space Administration (NASA) and the National Institute of Standards and Technology (NIST) are engaged in a program designed to ensure the radiometric calibration accuracy of sensors used in the Earth Observing System (EOS). The heart of this effort consists of measurement comparisons of radiometric sources using NIST-traceable radiometers . In the spring of 2001, an extensive comparison was held at the National Aeronautics and Space Administration's Goddard Space Flight Center (NASA's GSFC). The facility used was the class 10,000 cleanroom that is part of the Radiometric Calibration Facility (RCF) in the GSFC Space Geodesy Networks and Sensor Calibration Office (Code 920.1). A total of thirteen radiometers from eight different research groups measured a number of uniform radiance sources. In Part 1 of this article, we summarized the preliminary results for the GSFC integrating sphere sources ; here we conclude with the presentation of the preliminary results for the remaining sources. We present results of measurements of the NIST Portable Radiance Source (NPR) and a diffuse, high reflectance plaque illuminated by lamp standards of spectral irradiance. These sources are representative of the two most important types of spectral radiance standards. The NPR provided direct traceability to NIST ; the plaque source was used with two FEL lamp standards of spectral irradiance to evaluate the implications of the recent improvements in the NIST spectral irradiance scale  in a typical application used in the remote sensing community.
, Johnson, B.
and Barnes, R.
Radiometric Measurement Comparisons at NASA's Goddard Space Flight Center: Part II. Irradiance Lamp Comparisons and the NIST Sphere Source, The Earth Observer
(Accessed December 7, 2023)