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S-NPP

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project, or NPP, was launched on 28 October 2011 to collect and distribute remotely-sensed land, ocean, and atmospheric observations for the meteorological, oceanographic, terrestrial and global climate change communities. It aims to provide data continuity of these measurements from existing Earth-observing missions such as Aqua, Terra and Aura.  The NPP satellite is the first in a series designed to provide critical data to improve short-term weather forecasts and increase understanding of long-term climate change.

On 24 January 2012 at the annual meeting of the American Meteorological Society in New Orleans, NASA has renamed its newest Earth-observing satellite in honor of the late Verner E. Suomi, a meteorologist at the University of Wisconsin who is recognized widely as "the father of satellite meteorology." The NPOESS Preparatory Project (NPP) then became the Suomi National Polar-orbiting Partnership satellite, or Suomi NPP (S-NPP).

S-NPP is a pilot mission for the Joint Polar Satellite System (JPSS), which is the next generation polar-orbiting operational environmental satellite system for the USA. Onboard the S-NPP satellite, there are five state-of-the-art instruments/sensors.

The JPSS-1 (NOAA-20) is the second mission in the JPSS series, which is scheduled to launch in the fourth quarter of 2017. For the rest of JPSS series, their schedules are also planned and can be found at the NOAA Launch-Schedule webpage.

Instruments
  • ATMS – Advanced Technology Microwave Sounder instrument is the next generation cross-track microwave sounder providing atmospheric temperature and moisture for operational weather and climate applications.
  • CERES – Clouds and the Earth's Radiant Energy System instrument measures reflected sunlight and thermal radiation emitted by the Earth.
  • CrIS – Cross-track Infrared Sounder instrument is the first in a series of advanced operational sounders that provides more accurate, detailed atmospheric temperature and moisture observations for weather and climate applications.
  • OMPS – Advanced Ozone Mapping and Profiler Suite tracks the health of the ozone layer and measures the concentration of ozone in the Earth's atmosphere.
  • VIIRS – Visible Infrared Imaging Radiometer Suite collects visible and infrared imagery and global observations of land, atmosphere, cryosphere and oceans. VIIRS spectral coverage allows for ocean datasets similar to those from the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS) while providing slightly better spatial resolution (750 m) and improved global temporal coverage (1 day).  From the perspective of sea surface temperature (SST), VIIRS extends and improves upon the decadal series of measurements initiated by the Advanced Very High Resolution Radiometer (AVHRR) and MODIS.
VIIRS Instrument

VIIRS is the largest instrument onboard NPP, weighing in at 556 pounds (252 kilograms). Its data, collected from 22 channels across the electromagnetic spectrum, will be used to observe the Earth’s surface, including fires, ice, ocean color, vegetation, clouds, and land and SSTs.

The VIIRS instrument is a whiskbroom scanning radiometer with a field of regard of 112.56 degree in the cross-track direction. At a nominal altitude of 824 km, the swath width is 3060 km, providing full daily coverage both in the day and night side of the Earth. VIIRS's 22 spectral bands cover the spectrum between 0.412 µm and 12.01 µm, including 16 moderate resolution bands (M-bands) with a spatial resolution of 750 m at nadir, 5 imaging resolution bands (I-bands) – 375 m at nadir, and one panchromatic DNB with a 750 m spatial resolution throughout the scan. The M-bands include 11 Reflective Solar Bands (RSB) and 5 Thermal Emissive Bands (TEBs). The I-bands include 3 RSBs and 2 TEBs. 

VIIRS provides capabilities to produce higher resolution and more accurate SST measurements than currently available from the heritage AVHRR instrument on POES, as well as provide an operational capability for ocean-color observations and a variety of derived ocean-color datasets. SST is one of the key VIIRS ocean datasets and is included in the GHRSST project. 

Instrument Specifications

Spectral Bands
     Visible/Near IR:                                    9 plus day/night pan band
     Mid-Wave IR:                                                                           8
     Long-Wave IR:                                                                         4
Imaging Optics:                        19.1 cm aperture, 114 cm focal length
Orbit Average Power:                                                         200 Watts
Weight:                                                                                 275 kg
Data Acquisition Parameters:
    Scanned Swath:                                                     ±56°, 3000 km
    Horizontal Sample Interval on Ground:        <1.6 km @ end of scan
    Data Quantization:       12 bit –14 bit A/D converters for lower noise
    Data Rate:                                                        10.5 Mbps (max.)