Radiometric measurement comparisons play an important part in the pre-flight calibration and cross-calibration of EOS instruments. The primary goal of the radiometric measurement comparisons is to compare and validate the spectral radiance of integrating sphere sources and blackbodies as calibrated by the EOS instrument providers to that determined by national standards laboratories such as the National Institute of Standards and Technology (NIST) and the National Research Laboratory of Metrology (NRLM/Japan). A second goal of the comparisons is to compare spectral radiances determined by participants from outside laboratories using the integrating sphere sources and blackbodies as common targets. Outside laboratories include secondary standards calibration laboratories such as the NASA/GSFC Codes 614.4 and 613.3 Calibration Laboratories, the NASA/Ames Aircraft Calibration Facility, and laboratories engaged in vicarious calibration such as the University of Arizona Optical Sciences Center Remote Sensing Group. A third goal of the comparisons is to evaluate the findings in terms of measurement procedure and basic metrology.
In order to meet the comparison goals, a series of ultrastable transfer radiometers has been independently developed by participating metrology laboratories. The EOS Project Science Office enlisted the expertise of the NIST Optical Technology Division in designing, fabricating, and fully characterizing a set of three EOS transfer radiometers spanning the visible to thermal infrared wavelength regions. The University of Arizona Optical Sciences Center Remote Sensing Group has developed visible/near infrared and shortwave infrared filter radiometers. NRLM/Japan have developed a set of three visible/near infrared and two shortwave infrared filter radiometers in support of the calibration of the EOS ASTER instrument. NASA's GSFC Landsat 7 ETM+ Science Office developed a visible/near infrared radiometer incorporating filters used in the ETM+ satellite instrument. NASA's GSFC Code 614.4 Radiometric Calibration facility also participates in the comparisons with a scanning spectroradiometer.
Schedule
Information on Comparisons: 1995 to Present
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