VIIRS

VIIRS
Name	VIIRS
Mission type	Earth observation
Operator	National Oceanic and Atmospheric Administration / NASA
Manufacturer	Raytheon
Launch date	2011-10-28 (SNPP)
Instruments	Visible Infrared Imaging Radiometer Suite
Wavelength	Visible to infrared ( ~0.412–12.01 μm)
Spatial resolution	375 m (I-bands), 750 m (M-bands)
Orbit	Sun-synchronous
Status	Active/operational on multiple platforms

VIIRS is a spaceborne imaging radiometer developed to provide moderate-resolution, multispectral observations of Earth's surface, atmosphere, and oceans. It delivers calibrated measurements across visible, near-infrared, and thermal infrared bands to support global environmental monitoring, disaster response, and climate research. The instrument is a core payload on multiple polar-orbiting platforms and contributes to continuity of long-term records begun by sensors such as AVHRR and MODIS.

Overview

VIIRS is designed to measure reflected and emitted radiance in dozens of spectral channels to characterize phenomena ranging from ocean color to land surface temperature and nighttime lights. It succeeds and augments earlier sensors like Terra, Aqua, and NOAA-19 instruments, enabling synergy with datasets from Landsat and Sentinel-2 for higher-resolution context. Programs including Joint Polar Satellite System, Suomi National Polar-orbiting Partnership, and international collaborations with European Space Agency leverage VIIRS data for operational forecasting, environmental assessment, and scientific studies.

Instrument Design and Specifications

The instrument employs a rotating/two-sided scanning telescope feeding focal plane assemblies that separate channels into medium (M) and imaging (I) bands. Optical components were developed by contractors such as Ball Aerospace and fabricated to meet thermal stability requirements driven by missions like Jason-3 and GPM. Key specifications include multiple reflective and refractive elements, stray-light control inspired by heritage designs from SPOT and IKONOS, and detectors using mercury cadmium telluride and silicon arrays informed by work at NASA Goddard Space Flight Center and Jet Propulsion Laboratory. Resolution classes—375 m I-bands and 750 m M-bands—match requirements set by stakeholders including National Weather Service and United States Geological Survey for applications like land cover mapping and biomass estimation. Spectral coverage spans approximately 0.412 to 12.01 μm, configured to capture visible, near-infrared, shortwave infrared, and thermal infrared radiance for channels analogous to bands on MODIS and AVHRR.

Data Products and Processing

VIIRS processing chains are maintained by agencies such as NOAA and NASA, producing geolocated, calibrated radiances and higher-level products including surface reflectance, aerosol optical depth, sea surface temperature, and active fire detections. Standard Level-1B and Level-2 products are distributed through processing systems influenced by architectures from EUMETSAT and data centers like NOAA National Centers for Environmental Information. Data formats follow conventions compatible with tools from USGS EarthExplorer, Copernicus Open Access Hub, and analysis platforms employed at institutions including Columbia University and SCRIPPS Institution of Oceanography. Processing algorithms incorporate radiative transfer models developed by research groups at University of Colorado Boulder and Massachusetts Institute of Technology and use calibration coefficients traced to references such as MODIS Science Team heritage. Nighttime lights products are widely used in socio-economic studies and are cross-validated with datasets from DMSP-OLS.

Applications and Uses

VIIRS supports a broad spectrum of applications for stakeholders such as Federal Emergency Management Agency, World Meteorological Organization, and environmental NGOs like WWF. Oceanography applications include chlorophyll estimation, harmful algal bloom monitoring, and sea surface temperature mapping used by NOAA Fisheries and researchers at Woods Hole Oceanographic Institution. Land applications cover wildfire detection and burn scar mapping supporting agencies including CAL FIRE and international partners during events like the Australian bushfires. Atmospheric science uses aerosol and cloud products for air quality assessments associated with organizations such as Environmental Protection Agency. Urban studies employ nighttime lights to estimate electrification and population dynamics alongside work by World Bank and UN entities such as UN-Habitat.

Calibration and Validation

Radiometric, spectral, and geometric calibration strategies combine on-orbit maneuvers, vicarious calibration sites, and comparisons with reference instruments like MODIS and ground networks including AERONET. Calibration teams from NOAA NESDIS and NASA LaRC conduct lunar and solar calibrations, while validation campaigns coordinate with field sites operated by USGS and marine observatories like Hawaii Ocean Time-series. Cross-calibration efforts reference standards from institutions such as National Institute of Standards and Technology and intercomparisons with international missions from Japan Aerospace Exploration Agency and Indian Space Research Organisation ensure traceability. Degradation monitoring and detector nonlinearity corrections are addressed via procedures refined during missions including SeaWiFS and VIIRS successor developments.

Missions and Platforms

VIIRS instruments fly on platforms including the Suomi NPP satellite and instruments planned or flown on JPSS series spacecraft such as NOAA-20. International cooperation has informed payload requirements on follow-on polar platforms coordinated with entities like European Organisation for the Exploitation of Meteorological Satellites and bilateral efforts with Japan Meteorological Agency. Operational centers including NOAA Satellite Operations Facility manage tasking, downlink, and dissemination to users across academic institutions such as University of Maryland and operational services like National Snow and Ice Data Center.

Category:Earth observation satellites