Research Highlights: October 2018

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Landsat 8 OLI & TIRS On-Orbit Radiometric Performance

B. Markham Biospheric Sciences J. Barsi SSAI NASA GSFC; M. Montanaro RIT

Figure 1
Figure 2
  1. The Landsat-8 Operational Land Imager (OLI) continues its record of remarkable radiometric stability over 5+ years. The CA band change is the largest at ~1.3% over this period. All radiometric calibration techniques give consistent results within ~0.5%. Some degradation is apparent in working stim lamp output.
  2. The Landsat-8 Thermal Infrared Sensor (TIRS) is similarly extremely stable over the mission, changing in response to the on-board blackbody by <0.5%. The stability has allowed maintenance of the instrument calibration in spite of the need to reduce calibration data acquisition frequency due to scene select mirror encoder anomalies.

Name: Brian L. Markham, Biospheric Sciences, NASA GSFC
E-mail: Brian.L.Markham@nasa.gov
Phone: 301-614-6608

References:

Technical Description of Figures

Figure 1. The Landsat-8 OLI radiometric trends: (a) The signal-to-noise ratio of the Coastal Aerosol band at "typical" radiance levels over the mission life measured using the on-board calibration systems. (b) the radiometric responsivity normalized to an early mission date. The coastal aerosol shows the largest changes of all the OLI bands, but are still less than 1.5% in responsivity and 1% in signal-to-noise.

Figure 2. The Landsat-8 TIRS radiometric trends: (a) The noise-equivalent delta temperature of both bands at 300K over the mission life measured using the on-board calibration systems. (b) the radiometric responsivity normalized to an early mission date. On the primary electronics side (first 2 mission years) the response to the blackbody decreased 0.2% to 0.3%. On the secondary electronics side (after first 2 years), the response decreased 0.1% to 0.2%. Some portion of the change may relate to the blackbody as opposed to the instrument itself. About mission year 3, the operations concept was changed, with calibrations roughly twice a month versus twice an orbit. Noise performance has been stable.

Scientific significance, societal relevance, and relationships to future missions:

Inherent radiometric stability of remote sensing instruments as demonstrated by both the Landsat-8 OLI and TIRS, provides a strong basis for generating high quality consistent data products as are needed for detecting Earth surface changes over extended periods of time. This, combined with consistency between missions, which although not discussed here, has been part of the Landsat program for many years, provides Earth sciences the long term datasets they need.