An accurate on-orbit characterization of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership satellite is essential to satisfy the requirements from NOAA, NASA, and the general research community for high-quality operational and research products. NASA’s Land Science Investigator-led Processing System (LSIPS) sensor data records (SDRs) are utilized to assess the stability of the calibrated top of atmosphere reflectance over the deep convective clouds (DCCs) and over the Libya-4 desert site. The results from DCCs and desert show detector-to-detector (D2D) reflectance differences in the VIIRS reflective solar bands, 10 moderate-resolution bands (M-bands, M1 to M5, M7 to M11), and three imagery resolution bands (I-bands, I1-I3). More importantly, the D2D differences exhibit an increase in magnitude over time for bands M1 to M5 and I1 to I2, which induces noticeable striping and higher uncertainties in the downstream data products. The largest D2D difference is observed in bands M1 and M2, with magnitudes greater than 1.8% in trends among the 16 detectors and standard deviations less than 0.12% over time. The D2D stability assessment results over DCCs are consistent with those observed over the Libya-4 desert site. To improve the quality of the calibrated SDR reflectance data, NASA’s VIIRS characterization support team has improved the calibration algorithm to incorporate corrections based on these DCC measurements to mitigate the striping (detector differences) observed in the current version of the SDR. These improvements are planned to be included in the next mission reprocessing of the LSIPS land products.

The core of deep convective clouds (DCC) is one of the most consistent Earth targets. When viewed from space, the measurements have minimal impact from water vapor and aerosols and have been used as invariant scenes for calibration assessment for reflectance solar bands. DCC is also one of the coldest targets and can be used for assessing the calibration and product stability for infrared thermal emissive bands (TEB). The stability from the years 2003 to 2019 is analyzed for both Terra and Aqua moderate resolution imaging spectroradiometer (MODIS) long-wave infrared bands. Most bands exhibit very stable long-term trending. Terra band 30 shows the largest rate of change of 0.19  K  /  year. The Terra–Aqua difference is also analyzed. In general, for both Terra and Aqua, the long-wave infrared bands show good and stable detector uniformity. The impact of response change due to anomalies and events has been analyzed. Since the measurement bias over cold DCC is dominated by the offset term in the calibration equation, an assessment model is developed to estimate the offset bias between the mirror sides. The impact model is also developed to estimate the impact on higher brightness temperature measurements. The offset bias from the assessment modeling in this analysis is used as the input for impact modeling. The measurements over Dome-C, Ocean, and desert scenes are used to verify the impact model. These assessments are very helpful for MODIS TEB calibration and look-up table update procedure improvements.