The Visible Infrared Imaging Radiometer Suite (VIIRS) is a sensor designed and manufactured by the

Raytheon Company Raytheon is a business unit of RTX Corporation and is a major List of United States defense contractors, U.S. defense contractor and industrial corporation with manufacturing concentrations in weapons and military and commercial electronics. Fou ...

on board the polar-orbiting Suomi National Polar-orbiting Partnership (Suomi NPP),

NOAA-20 NOAA-20, designated JPSS-1 prior to launch, is the first of the United States National Oceanic and Atmospheric Administration's latest generation of U.S. polar-orbiting, non-geosynchronous, environmental satellites called the Joint Polar Sate ...

, and

NOAA-21 NOAA-21, designated JPSS-2 prior to launch, is the second satellite in National Oceanic and Atmospheric Administration (NOAA)'s latest series of U.S. polar-orbiting, non-geosynchronous, environmental satellites, known as the Joint Polar Satel ...

weather satellite A weather satellite or meteorological satellite is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites are mainly of two types: polar orbiting (covering the entire Earth asyn ...

s. VIIRS is one of five key instruments onboard Suomi NPP, launched on October 28, 2011. VIIRS is a whiskbroom scanner

radiometer A radiometer or roentgenometer is a device for measuring the radiant flux (power) of electromagnetic radiation. Generally, a radiometer is an infrared radiation detector or an ultraviolet detector. Microwave radiometers operate in the micro ...

that collects imagery and radiometric measurements of the land, atmosphere,

cryosphere The cryosphere is an umbrella term for those portions of Earth's surface where water is in solid form. This includes sea ice, ice on lakes or rivers, snow, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost). Thus, there ...

, and oceans in the visible and

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

bands of the

electromagnetic spectrum The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high ...

. VIIRS is capable of generating two data processing streams that result in two different sets of land products, with global coverage every 14 hours. One is produced by

NOAA The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with forecasting weather, monitoring oceanic and atmospheric conditions, charting the seas, conducting deep-sea exploratio ...

, and provides operational data for use by the

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

. These are known as environmental data records (EDRs). The other stream is from

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

, and is intended to contribute to the larger scientific community. These are known as Earth System Data Records (ESDRs). VIIRS's main uses include monitoring and investigating changes and properties in surface vegetation, land cover/use, the hydrologic cycle, and the Earth's energy budget over both regional and global scales. The combination of MODIS, AVHRR, and VIIRS data sets will allow for the assessment of how climate change has affected the Earth's surface over the past ~20 years.

Mission overview

VIIRS was launched on board Suomi NPP by a United Launch Alliance

Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family, derived directly from the Delta 3000, and entered service in ...

rocket from the

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in Key West, Florida * Vandenberg S ...

at 5:48 am EDT on 28 Oct, 2011. VIIRS was designed to expand upon the data collected by the aging MODIS and AVHRR sensors by collecting radiometric measurements of Earth in the visible and infrared spectra. This data is used to provide insight into the properties and dynamics of different geophysical phenomena, including: aerosol and cloud properties, sea, land and ice surface temperatures, ice motion, fires, and the albedo of Earth. VIIR's main objectives include the monitoring and investigation of changes and properties in vegetation, land cover/use, the hydrologic cycle, and the earth's energy budget over both global and regional scales. This information is useful in furthering our understanding of global climate change. The combination of MODIS, AVHRR, and VIIRS datasets will permit a comprehensive assessment of how climate change has effected the land surface over the past ~20 years.

Specifications

VIIRS has a swath width of 3060 km at the satellite's average altitude of 829 km. This swath width is able to provide complete coverage of Earth across the day. The VIIRS instrument can collect data in 22 different spectral bands of the electromagnetic spectrum, in the wavelengths between 0.412 μm and 12.01 μm. The

spatial resolution In physics and geosciences, the term spatial resolution refers to distance between independent measurements, or the physical dimension that represents a pixel of the image. While in some instruments, like cameras and telescopes, spatial resoluti ...

of the sensor depends on the band of the electromagnetic spectrum. Out of the 22 different spectral bands the sensor has, 16 are moderate resolution bands (M-bands) which have a spatial resolution of 750m at the

Nadir The nadir is the direction pointing directly ''below'' a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface. The direction opposite of the nadir is the zenith. Et ...

. The other six bands are made up of five imaging resolution bands (I-bands), which have a spatial resolution of 375m at the nadir, and one day/night panchromatic band with a spatial resolution of 750m. VIIRS imaging optics include a 19.1 cm Aperture and a 114 cm

Focal length The focal length of an Optics, optical system is a measure of how strongly the system converges or diverges light; it is the Multiplicative inverse, inverse of the system's optical power. A positive focal length indicates that a system Converge ...

. The average orbit power for the instrument is 200 watts. In total the instrument weighs 275 kg.

Spatial resolution

The VIIRS instrument provides 22 spectral bands at two native

s, 375 meters (m) and 750 m, which are resampled to three nominal spatial resolutions 500 m, 1,000 m, and 5,600 m (0.05 degrees) in the NASA produced data products.

References

External links

* * VIIRS Interactive global map of fires with charts and downloads: http://viirsfire.geog.umd.edu/map/viirsMap.php * VIIRS image examples (CIMSS Satellite Blog): http://cimss.ssec.wisc.edu/goes/blog/archives/category/viirs {{Use American English, date=March 2014 Weather imaging satellite sensors Infrared imaging 2011 introductions