Visible Infrared Imaging Radiometer Suite (VIIRS) Global Area Coverage (VGAC), Version 1

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument represents a significant change from the historical weather satellite observations. For example, there are several differences in observation style, channel, structure, etc. from the Advanced Very High Resolution Radiometer (AVHRR) which flew on low earth orbit satellites since the 1970s. Several longstanding climate data records were developed expressly using the AVHRR instrument. The VIIRS Global Area Coverage (VGAC) dataset is an attempt to more closely bridge the old technology with the new. The VGAC data file provides one orbit of VIIRS observations (22 channels: 14 Reflective Solar Bands; 7 Thermal Emissive Bands and 1 Day/Night Band) that have been degraded in resolution to approximate the AVHRR GAC resolution. Each channel is provided using the same swath that simulates a 3.9 km resolution scan. The moderate resolution VIIRS channels each have the mean value of the radiance in that 3.9 km region. Some of the higher resolution imaging channels (I channels) contain more statistical information, including maximum and minimum radiances, which benefit algorithms like cloud and surface retrievals.