Using Collocated VIIRS Observations for CrIS Scene Characterization toward Extending Data Utilization

Abstract

Given the fact that Cross-track Infrared Sounder (CrIS) and the Visible Infrared Imaging Radiometer Suite (VIIRS) currently are onboard the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite and will continue to be carried on the same platform of future Joint Polar Satellite System (JPSS) satellites for the next decade, it is desirable to collocate VIIRS measurements with CrIS instantaneous field of view (FOV) to characterize CrIS sub-pixel scene features. In this paper, an accurate and fast collocation method to collocate VIIRS measurements within CrIS instantaneous field of view (IFOV) directly based on line-of-sight (LOS) pointing vectors is developed. The geolocation of CrIS observations is adjusted to perfectly align CrIS with VIIRS to minimize the collocation uncertainties. Finally, the potential application of how the sub-pixel inhomogeneous scene features derived collocated VIIRS pixels impact on CrIS radiance data quality, such as extremely cold or hot Earth scenes as well as Instrument Line Shape (ILS) shift, are presented.