The Effects of VIIRS Detector-Level and Band-Averaged Relative Spectral Response Differences Between S-NPP and NOAA-20 on the Thermal Emissive Bands

Abstract

The Joint Polar Satellite System-1 (renamed NOAA-20 after reaching the polar orbit) was successfully launched on November 18, 2017, into an afternoon orbit with a local equator crossing time of ∼1:30 P.M., in the same orbital plane as the Suomi National Polar-orbiting Partnership (S-NPP) but with a time separation of 50 min. The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) will become the primary operational imager succeeding the VIIRS onboard S-NPP, which has been in orbit for more than six years. Although the VIIRS onboard S-NPP and NOAA-20 have identical designs, there are small differences in the relative spectral response (RSR) in most bands. Previous studies have shown that minor differences in the S-NPP RSRs at thermal emissive bands (TEBs) can lead to several effects at the detector level, such as striping in sensor data record (SDR) products. Such differences may explain the striping pattern found in S-NPP VIIRS sea surface temperature (SST) products. This article analyzes the detector-level and operational band-averaged RSRs for NOAA-20 VIIRS TEBs and examines the radiometric response to them using the line-by-line radiative transfer model at a very high spectral resolution for convolving with the RSRs. We also evaluate the impact of RSR differences between S-NPP and NOAA-20 for radiometric biases and potential striping in VIIRS TEB SDR brightness temperature. This article will contribute toward measurement consistency for long-term observations in the thermal infrared bands and ensure the quality of retrieval data produced by VIIRS, such as SST, fire, and other retrievals. Index Terms-Line-by-line radiative transfer model (LBLRTM), relative spectral response (RSR), sensor data record (SDR) product, thermal emissive band (TEB), Visible Infrared Imaging Radiometer Suite (VIIRS). I. INTRODUCTION

Turning Night into Day: The Creation and Validation of Synthetic Nighttime Visible Imagery Using the Visible Infrared Imaging Radiometer Suite (VIIRS) Day–Night Band (DNB) and Machine Learning

“…Quantitative metrics have been based on pattern evaluation and structural similarities versus on data from observed measurements. Lin and Cao (2019) demonstrated that the relative spectral responses (RSR) in the IR spectrum for VIIRS on these satellite are not identical, differing between 0.18 K -0.06 K. However, this minimal difference in sensor sensitives is within documented performance limits and thus data from VIIRS off both systems was included when creating the training and validation data set. Additionally, although there are both seasonal and latitudinal variations of the standard atmosphere profile causing differing RSRs in the temporal and spatial region of study, we chose to accept these differences as within reasonable limits for data.…”

Characterization and Validation of ECOSTRESS Sea Surface Temperature Measurements at 70 m Spatial Scale

“…In VIIRS JPSS1, the non-uniformities increase with source temperature [96], which could also be related to differences in spectral response. These detector-to-detector differences in the spectral response of VIIRS lead to detector-to-detector variations in retrieved temperature of up to 7 mK [97]. By comparison, the detector-todetector differences in ECOSTRESS brightness temperatures are up to 375 mK in the 8.78 and 10.49 µm bands and up to 875 mK in the 12.09 µm band (Figure 13).…”