Landsat-7 ETM+ radiometric stability and absolute calibration

B. L. Markham; J. L. Barker; J. A. Barsi; E. Kaita; K. J. Thome; D. L. Helder; Frank Don Palluconi; J. R. Schott; Pat Scaramuzza

doi:10.1117/12.462998

USGS · 70023929

Landsat-7 ETM+ radiometric stability and absolute calibration

B. L. Markham·J. L. Barker·J. A. Barsi·E. Kaita·K. J. Thome·D. L. Helder·Frank Don Palluconi·J. R. Schott·Pat Scaramuzza

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Abstract

Launched in April 1999, the Landsat-7 ETM+ instrument is in its fourth year of operation. The quality of the acquired calibrated imagery continues to be high, especially with respect to its three most important radiometric performance parameters: reflective band instrument stability to better than ??1%, reflective band absolute calibration to better than ??5%, and thermal band absolute calibration to better than ??0.6 K. The ETM+ instrument has been the most stable of any of the Landsat instruments, in both the reflective and thermal channels. To date, the best on-board calibration source for the reflective bands has been the Full Aperture Solar Calibrator, which has indicated changes of at most -1.8% to -2.0% (95% C.I.) change per year in the ETM+ gain (band 4). However, this change is believed to be caused by changes in the solar diffuser panel, as opposed to a change in the instrument's gain. This belief is based partially on ground observations, which bound the changes in gain in band 4 at -0.7% to +1.5%. Also, ETM+ stability is indicated by the monitoring of desert targets. These image-based results for four Saharan and Arabian sites, for a collection of 35 scenes over the three years since launch, bound the gain change at -0.7% to +0.5% in band 4. Thermal calibration from ground observations revealed an offset error of +0.31 W/m 2 sr um soon after launch. This offset was corrected within the U. S. ground processing system at EROS Data Center on 21-Dec-00, and since then, the band 6 on-board calibration has indicated changes of at most +0.02% to +0.04% (95% C.I.) per year. The latest ground observations have detected no remaining offset error with an RMS error of ??0.6 K. The stability and absolute calibration of the Landsat-7 ETM+ sensor make it an ideal candidate to be used as a reference source for radiometric cross-calibrating to other land remote sensing satellite systems.

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B. L. Markham, J. L. Barker, J. A. Barsi, E. Kaita, K. J. Thome, D. L. Helder, Frank Don Palluconi, J. R. Schott, Pat Scaramuzza. 2002. Landsat-7 ETM+ radiometric stability and absolute calibration. https://doi.org/10.1117/12.462998

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