Evaluation of Himawari-8 AHI geospatial calibration accuracy using SNPP VIIRS SNO data

Abstract

Japan Meteorological Agency (JMA) Himawari-8 Advanced Himawari Imager (AHI) is the first in the series of next-generation geostationary (GEO) weather instruments. It has 16 spectral solar reflective and emissive bands located in three focal plane modules (FPM): one visible and near-infrared (VNIR) FPM, one midwave infrared (MWIR) FPM, and one longwave infrared (LWIR) FPM. All the AHI bands are geo-spatially calibrated to provide continuous environmental measurements from the Asian-Pacific area for the weather forecasting, disaster monitoring, and longterm climatic change studies. This study is to evaluate the navigation and co-registration accuracies of three AHI bands at the three FPMs using the simultaneous nadir observations (SNO) of Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) I-band images. The preliminary results showed that the mean navigation difference between the two instruments is within 0.5 AHI pixels at 2km spatial resolution. The AHI band-to-band co-registration (BBR) difference between the two thermal bands is generally less than 0.2 pixels, better than the BBR between the VNIR and IR bands which ranges between 0.2 to 0.7 pixels during the study period.