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

Raytheon Company The Raytheon Company was a major U.S. defense contractor and industrial corporation with manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft unti ...

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 Sat ...

, and

NOAA-21 NOAA-21, designated JPSS-2 prior to launch, is the second of the United States National Oceanic and Atmospheric Administration (NOAA)'s latest generation of U.S. polar-orbiting, non-geosynchronous, environmental satellites called the Joint Po ...

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 can be polar orbiting (covering the entire Earth asynchronously), or ge ...

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

whiskbroom scanner A whisk broom or spotlight sensor, also known as an across-track scanner, is a technology for obtaining satellite images with optical cameras. It is used for passive remote sensing from space. In a whisk broom sensor, a mirror scans across the satel ...

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 microwave w ...

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

cryosphere ] The cryosphere (from the Ancient Greek, Greek ''kryos'', "cold", "frost" or "ice" and ''sphaira'', "globe, ball") is an all-encompassing term for those portions of Earth's surface where water is in solid form, including sea ice, lake ice, ri ...

, and oceans in the Visible spectrum, visible and

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

bands of the

electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...

. 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 (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

, 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 agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

, 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. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 va ...

rocket from the

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USS General Harry Taylor (AP-145), USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in K ...

at 5:48 am EDT on 28 Oct, 2011. VIIRS was designed to expand upon the data collected by the aging MODIS and

AVHRR The Advanced Very-High-Resolution Radiometer (AVHRR) instrument is a space-borne sensor that measures the reflectance of the Earth in five spectral bands that are relatively wide by today's standards. AVHRR instruments are or have been carried b ...

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 In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

. 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 resolutio ...

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 (, ; ar, نظير, naẓīr, counterpart) 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 direc ...

. 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 In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

and a 114 cm

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

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

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