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The VIIRS instruments onboard the Suomi National Polar-orbiting Partnership (S-NPP) and NOAA-20 (N20) spacecraft have provided openly-public data for scientific studies and to address global issues for close to one decade and over three years, respectively. VIIRS has 7 Thermal Emissive Bands (TEB) with central wavelengths that range from 3.7 μm to 12.0 μm and are calibrated on-orbit using observations from its onboard blackbody calibrator. The on-orbit performance of the S-NPP and N20 VIIRS TEB has been assessed in the past and shown to be quite stable with marginal degradation. However, in order to maintain VIIRS’ rich, well-calibrated archive of multispectral imagery and data, Earth targets should be regularly monitored to track its on-orbit long-term stability as well as the consistency between VIIRS sensors. This manuscript focuses on evaluating the TEB on-orbit radiometric calibration stability for both VIIRS instruments using an in situ ocean site - moored buoy located in the Pacific Ocean that belongs to the NOAA’s National Data Buoy Center – as reference. Furthermore, it will assess the calibration consistency between VIIRS sensors. Only cloud-free, nighttime VIIRS TEB retrievals are used in this study. A normalization methodology is applied to standardize the VIIRS data to the in situ data. Results indicate excellent S-NPP VIIRS TEB on-orbit performance (all mission-long temperature drifts are within -0.16 K) and good consistency between VIIRS sensors (average S-NPP-to- N20 temperature differences for most bands are within -0.20 K) over ocean temperatures. In the future, similar strategies can be employed to monitor the TEB on-orbit radiometric calibration stability for the VIIRS instruments that will be onboard the Joint Polar Partnership System-2 (JPSS-2), JPSS-3, and JPSS-4 satellite missions.
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