Share Email Print
cover

Proceedings Paper

Radiometric measurement comparisons using transfer radiometers in support of the calibration of NASA's Earth Observing System (EOS) sensors
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

EOS satellite instruments operating in the visible through the shortwave infrared wavelength regions (from 0.4 micrometer to 2.5 micrometer) are calibrated prior to flight for radiance response using integrating spheres at a number of instrument builder facilities. The traceability of the radiance produced by these spheres with respect to international standards is the responsibility of the instrument builder, and different calibration techniques are employed by those builders. The National Aeronautics and Space Administration's (NASA's) Earth Observing System (EOS) Project Science Office, realizing the importance of preflight calibration and cross-calibration, has sponsored a number of radiometric measurement comparisons, the main purpose of which is to validate the radiometric scale assigned to the integrating spheres by the instrument builders. This paper describes the radiometric measurement comparisons, the use of stable transfer radiometers to perform the measurements, and the measurement approaches and protocols used to validate integrating sphere radiances. Stable transfer radiometers from the National Institute of Standards and Technology, the University of Arizona Optical Sciences Center Remote Sensing Group, NASA's Goddard Space Flight Center, and the National Research Laboratory of Metrology in Japan, have participated in these comparisons. The approaches used in the comparisons include the measurement of multiple integrating sphere lamp levels, repeat measurements of select lamp levels, the use of the stable radiometers as external sphere monitors, and the rapid reporting of measurement results. Results from several comparisons are presented. The absolute radiometric calibration standard uncertainties required by the EOS satellite instruments are typically in the plus or minus 3% to plus or minus 5% range. Preliminary results reported during eleven radiometric measurement comparisons held between February 1995 and May 1998 have shown the radiance of integrating spheres agreed to within plus or minus 2.5% from the average at blue wavelengths and to within plus or minus 1.7% from the average at red and near infrared wavelengths. This level of agreement lends confidence in the use of the transfer radiometers in validating the radiance scales assigned by EOS instrument calibration facilities to their integrating sphere sources.

Paper Details

Date Published: 28 December 1999
PDF: 13 pages
Proc. SPIE 3870, Sensors, Systems, and Next-Generation Satellites III, (28 December 1999); doi: 10.1117/12.373186
Show Author Affiliations
James J. Butler, NASA Goddard Space Flight Ctr. (United States)
B. Carol Johnson, National Institute of Standards and Technology (United States)
Steven W. Brown, National Institute of Standards and Technology (United States)
Howard W. Yoon, National Institute of Standards and Technology (United States)
Robert A. Barnes, Science Applications International Corp. (United States)
Brian L. Markham, NASA Goddard Space Flight Ctr. (United States)
Stuart F. Biggar, Optical Sciences Ctr./Univ. of Arizona (United States)
Edward F. Zalewski, Optical Sciences Ctr./Univ. of Arizona (United States)
Paul R. Spyak, Optical Sciences Ctr./Univ. of Arizona (United States)
John W. Cooper, Raytheon STX (United States)
Fumihiro Sakuma, National Research Lab. of Metrology (Japan)


Published in SPIE Proceedings Vol. 3870:
Sensors, Systems, and Next-Generation Satellites III
Hiroyuki Fujisada; Joan B. Lurie, Editor(s)

© SPIE. Terms of Use
Back to Top