Overview
VIIRS Global Area Coverage (VGAC) is a comprehensive satellite record that provides reprojected data from the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard multiple polar-orbiting satellites. VGAC serves as a critical component of NOAA’s satellite climate data portfolio, designed to extend the life of historic CDRs thereby supporting long-term climate monitoring and research applications.
Current Status
VGAC is under active development, with ongoing work to expand multi-satellite support across all JPSS platforms, implement cloud-based parallel processing architecture, and establish routine operational production capabilities.
Last updated: February 2026
Data Access
NCEI Archive
Operational and archived data at NCEI are available with a 3-5 week latency. Some of the data are available by HTTPS download
For the entire archive period of record, users would need to contact NCEI directly: ncei.orders@noaa.gov
Routinely updated data
The operational and archived data are produced by and available from NCICS (in cooperation with NCEI). The data are available generally with a 3 hour latency at their anonymous FTP server:
ftp://filsrv.cicsnc.org/vgac/data/
Data will also likely be available on NODD (NOAA Open Data Dissemination)
Presentations and papers
Data Description
The data are reprojected to provide a product similar to legacy AVHRR GAC data. This includes:
- Files organized by orbit (instead of by granule).
- Channels provided at 3.9 km resolution (which approximates the original GAC resolution)
Data are routinely produced for NOAA 20 and 21.
Applications
VGAC supports a wide range of scientific and operational applications:
- Climate Record Development: Long-term, consistent observations for climate trend analysis and monitoring
- Environmental Monitoring: Tracking changes in Earth’s atmosphere, land surface, and oceans
- Research Support: Providing validated satellite data for academic and scientific research
- International Coordination: Supporting collaborative efforts with international partners including EUMETSAT
- Data Continuity: Ensuring seamless transition between satellite generations for uninterrupted climate records
The standardized calibration and global coverage make VGAC particularly valuable for studies requiring consistent observations over extended time periods.
Technical Details
VGAC employs modern data processing approaches optimized for climate data record production:
- Processing Architecture: Python-based algorithms deployed in cloud environments (AWS)
- Scalability: Designed for routine operational processing with parallel processing capabilities
- Integration: Compatible with existing NOAA Open Data Dissemination (NODD) systems
The technical implementation emphasizes practical solutions that bridge research innovation with operational requirements, ensuring sustainable long-term production of this critical climate dataset.