Evaluating radiometric consistency between Suomi NPP VIIRS and NOAA-19 AVHRR using extended simultaneous nadir overpass in the low latitudes

Abstract

The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi NPP has been undergoing extensive calibration/validation efforts in order to produce high quality weather and climate quality satellite data products. VIIRS absolute radiometric accuracy and consistency can be achieved by inter-comparing its measurements with other well calibrated instruments such as AQUA MODIS. VIIRS moderate resolution bands compared with matching MODIS bands at North African desert has shown that that the radiometric bias for channels M-1 through M-8 is less than 2%. VIIRS is a follow on mission for MODIS and AVHRR. In an effort to evaluate radiometric consistency of VIIRS with multi-decadal global earth observations from AVHRR, this study uses SNO-x approach to inter-compare NOAA-19 AVHRR measurements with VIIRS at North African desert over VNIR region. The radiometric consistency is evaluated and the uncertainty due to spectral differences is quantified using hyperspectral measurements from EO-1 Hyperion. In addition, the Antarctica Dome C site is used to estimate radiometric bias between AVHRR and VIIRS. AVHRR bias relative to VIIRS at Dome C is well within 0.5% for band 1 and 2% for band 2 compared to bias estimated at the desert sites using the SNO-x technique.