The daily images for Sea Ice Today now uses input data from the JAXA GCOM-W1 AMSR2 passive microwave instrument. AMSR2 replaces the previous data source, the Defense Meteorological Satellite Program (DMSP) SSMIS passive microwave instrument. For further details, see the NSIDC news announcement: New version release: NOAA/NSIDC Sea Ice Index, Version 4.