Progress in the calibration/validation of VIIRS on Suomi NPP and J1

Abstract

This paper presents the recent progress in the cal/val of the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi National Polar Orbiting Partnership (NPP) since launch, and Joint Polar Satellite System (JPSS) J1 which will be launched in 2017. The Suomi NPP VIIRS instrument continues to perform well with a very stable calibration according to extensive comparisons with other instruments and at vicarious validation sites. The calibration accuracy for most bands meet the specification and user needs, although additional efforts are being made to meet more stringent needs such as ocean color applications. The VIIRS Sensor Data Records (SDR) have been operationally used at the Alaska National Weather Service, and have been used to generate a large number of environmental data records ranging from aerosols, fire, to ocean color, sea surface temperature, vegetation, and many others. However, since many updates have been made to the operational processing of VIIRS since launch, inconsistency exists in the long term data records. To address this issue, the VIIRS SDR team is preparing for the reprocessing of the VIIRS historical data using the new automated calibration module RSBAutocal, with the latest calibration coefficients. The reprocessed data will be more consistent over the entire history of VIIRS with all known corrections. At the same time, significant efforts are devoted to the prelaunch calibration of the JPSS J1 VIIRS. While in general the J1 VIIRS performance meets specifications, there are performance waivers and as a result, mitigations have to be developed. This includes the implementation of a new aggregation scheme to address the nonlinear response of the VIIRS Day/Night Band (DNB). Other waivers include the larger than expected polarization sensitivity which will impact the ocean color bands and additional corrections will be needed postlaunch. In addition, the team has also been performing a trade study for adding a water vapor band to future VIIRS. Many of these efforts have been documented in the VIIRS special issue in the remote sensing open access journal which is being finalized to reach out to a broader user community.