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Progress and lessons from MODIS calibration intercomparison using ground test sites
Calibration accuracy and stability are key performance parameters for Earth-observing satellites. They have direct impact on the quality of science data products derived from sensor observations. Meanwhile, calibration consistency between spectral bands or among sensors also plays a critical role wh...
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Published in: | Canadian journal of remote sensing 2010-10, Vol.36 (5), p.540-552 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Calibration accuracy and stability are key performance parameters for Earth-observing satellites. They have direct impact on the quality of science
data products derived from sensor observations. Meanwhile, calibration consistency between spectral bands or among sensors also plays a critical role
when deriving data products using multiple spectral bands and constructing long-term climate data records (CDR) using observations made by different
sensors. The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key instrument for the National Aeronautics and Space Administration (NASA)
Earth Observing System (EOS) Terra and Aqua missions. To maintain its on-orbit calibration accuracy and monitor its calibration stability, MODIS was
designed and built with a set of onboard calibrators (OBCs), which can be operated continuously or on an as needed basis. In addition to regular
onboard calibration activities, extensive efforts have been made by MODIS calibration scientists and members of the MODIS Characterization Support
Team (MCST) to validate the calibration accuracy of each sensor and to quantify the calibration consistency between both Terra and Aqua MODIS. This
paper provides a brief description of MODIS on-orbit calibration methodologies and an overview of recent progress and lessons learned from MODIS
calibration intercomparison studies through the use of ground reference sites. Specifically, the simultaneous nadir overpass (SNO) and double
difference approaches over invariant reference sites, such as the Dome C, Libya-4 desert, and Lake Tahoe buoy sites, are illustrated. Examples derived
from different intercomparison approaches and their applications for different sensors and spectral bands are presented, focusing on examining their
calibration differences. Results from the Libya-4 desert site show that Terra and Aqua MODIS 0.65 and 0.85 µm channels have been well
calibrated, with excellent long-term stability of better than 1.0%. Using the SNO approach, the Terra and Aqua MODIS calibration consistency is found
to be within 1.5% and 0.6% for the 0.65 and 0.85 µm channels, respectively, and 0.02 K and 0.04 K for the 11 and 12 µm channels,
respectively. |
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ISSN: | 0703-8992 1712-7971 |
DOI: | 10.5589/m10-082 |