Estimating the VIIRS Thermal Emissive Band Response Versus Scan (RVS) and Calibration Offsets Using On-Orbit Pitch Maneuver Data

The Visible Infrared Imaging Radiometer Suite (VIIRS) is onboard the Suomi National Polar-orbiting Partnership (S-NPP) and the National Oceanic and Atmospheric Administration-20 (NOAA-20) satellites. This study presents a method for estimating VIIRS thermal emissive band (TEB) response versus scan (RVS) and calibration offsets simultaneously using on-orbit pitch maneuver data (METHOD2021). Raw Earth view (EV) RVS is estimated using an existing method (METHOD2019), with prelaunch RVS and calibration offsets as first guesses. Errors in the calibration offset are derived based on a prelaunch data-based assumption. Moreover, RVS and calibration offsets are optimized iteratively using the updated calibration coefficients until results converge. Compared to the METHOD2019, the METHOD2021-derived RVS is not affected by errors in the calibration offsets. Evaluation results using independent co-located Cross-track Infrared Sounder (CrIS) observations indicate that the METHOD2021 could effectively mitigate NOAA-20 scan angle- and scene temperature-dependent biases in M15, M16, and I5, as well as the cold bias in S-NPP M15. S-NPP TEB striping at cold scene temperatures can also be significantly reduced. Furthermore, NOAA-20 I5 and M15 measurements become more in family with S-NPP VIIRS and other radiometers at extremely low temperatures. Our analysis indicates that the impacts of METHOD2021 and METHOD2019 on TEB sensor data records (SDRs) are generally comparable. The METHOD2019 is simpler, while METHOD2021 better explains the root causes of the VIIRS TEB scan angle- and scene temperature-dependent biases. Both can be used for improving VIIRS TEB on-orbit calibration, especially at cold scenes.

I. Introduction

The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (S-NPP) and the National Oceanic and Atmospheric Administration-20 (NOAA-20) satellites were launched in October 2011 and November 2017, respectively [1], [2]. VIIRS has 22 spectral bands, including 14 reflective solar bands (RSBs, M1–M11, and I1–I3), seven thermal emissive bands (TEBs, M12–M16, I4, and I5), and one panchromatic day/night band (DNB). Among the seven TEBs, there are three mid-wave infrared (MWIR; M12, M13, and I4) and four long-wave infrared (LWIR; M14–M16 and I5) bands on VIIRS, with center wavelengths from 3.7 to . NOAA-20 and S-NPP VIIRS TEB sensor data records (SDRs) are used for deriving a variety of environmental and climate data records, such as sea surface temperature, land/ice surface temperature, active fire, and cloud properties. Quality of the VIIRS TEB SDR products and accuracy of their calibration are essential for these applications.