EOS Volcanology Logo EOS Volcanology Acronyms List

EOSDIS Core System Project Acronyms List:
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AIRS: Atmospheric Infrared Sounder

EOS instrument, planned for the PM-1 satellite platform (launch in 2000). An array grating spectrometer for measuring upward radiance at wavelengths between 0.4 to 1.0, 3.74 to 4.61, 6.20 to 8.22, and 8.8 to 15.4 micrometers, at a spectral resolution (lambda / delta lambda) of 1200 and a spatial resolution of 13.5 km at nadir.

ASAR: Envisat Advanced Synthetic Aperture Radar

An advanced synthetic aperture radar has been selected as the payload for the Envisat-1 payload, which has a planned launch in 2000. This C-band (5.6 cm wavelength) radar represents the next evolutionary step from ERS-2, and will have a variety of swath widths, including a wide swath mode that has a 100 m pixel size and 405 km swath. The radar will have dual polarization (VV like ERS-1 and ERS-2, and a new HH polarization capability). Also new for a European radar, there will be a variable incidence angle, from 15 to 45 degrees. Envisat's orbit has been selected as a 98 degree inclination orbit at 800 km altitude, which provides 35-day exact repeat coverage (i.e., identical to ERS-1 and ERS-2). The time of equatorial crossing for Envisat is 10:00 a.m. on the descending pass, which is comparable to the 10:30 a.m. equatorial crossing for the EOS AM platforms.

ASTER: Advanced Spaceborne Thermal Emission and Reflection Radiometer

EOS instrument, planned for the AM-1 platform (launch in 1998). Imaging radiometer providing high spatial resolution images of the Earth's surface and clouds using 14 multispectral bands from visible through thermal infrared wavelengths.

AVHRR: Advanced Very High-Resolution Radiometer

NOAA instrument, flown on NOAA satellites since 1978. Five spectral channels usually located at 0.58-0.68, 0.72-1.1, 3.55-3.93, 10.3-11.3, and 11.5-12.5 micrometers. Instantaneous field of view of 1 km at nadir, up to 7 km off nadir.

DEM: Digital elevation model

Topography in digital format.

EOS: Earth Observing System

A series of polar-orbiting and low-inclination satellites for global observations of the land surface, biosphere, solid earth, atmosphere, and oceans. EOS is a NASA mission planned to provide systematic and continuous observations of the Earth for a minimum of 15 years.

EOSP: Earth Observing Scanning Polarimeter

EOS instrument, planned for the AM-2 and AM-3 satellite platforms (launches in 2003 and 2008). Cross track scanning polarimeter that globally maps radiance and linear polarization of reflected and scattered sunlight for 12 spectral bands in the wavelength range 0.41 to 2.25 micrometers. Instrument scans from limb to limb (+/- 56 degrees) in the cross-track or along-track direction. Spatial resolution is 10 km at nadir. Provides global aerosol distribution and cloud properties such as optical thickness and phase.

Earth Remote-Sensing Satellite-1

Data from the first European remote sensing satellite instrument ERS-1 have been archived since 7 September 1991, and operations went into stand-by mode in June 1996. An almost identical satellite instrument ERS-2 began collecting data October 1995. ERS-1 and ERS-2 include an imaging radar system designed primarily for oceanography and sea ice investigations. The radar operates at C-band (5.6 cm wavelength), has VV polarization, and has a fixed incidence angle (23 degrees). Spacecraft provides a swath width of 100 km, but it does not have a tape recorder, so can only transmit data to ground stations in direct line-of-sight.

GLAS: Geoscience Laser Altimeter System

EOS instrument, planned for the ICESat-1 platform (launch in 2001). Nadir-pointed laser altimeter that can measure cloud heights and aerosol vertical structure. Uses Nd:YAG laser with 1.064 and 0.532 micrometer output.

GMS: Geostationary Meteorological Satellite

This Japanese weather satellite carries a VISSR instrument (Visible and Infrared Spin Scan Radiometer) to acquire images in the visible (0.5-0.75 micrometers) and infrared (10.5-12.5 micrometers). At nadir, the spatial resolution is 1.25 km in the visible and 5 km in the infrared. GMS is part of Japan's Earth Observation Satellites Program. The first GMS was launched in 1977. The currently operating instrument, GMS-5, was launched in 1995.

GOES: Geostationary Operational Environmental Satellite

NOAA weather satellites (GOES-EAST and GOES-WEST) which use the VISSR instrument (Visible and Infrared Spin Scan Radiometer) to acquire images in the visible (0.54-0.7 micrometers) and infrared (10.5-12.6 micrometers). At nadir, the spatial resolution is 0.9 km in the visible and 7.4 km in the infrared. GOES instruments have been flown since 1974.

GPS: Global Positioning System

HIRS, HIRS/2, and HIRS/3: High-Resolution Infrared Sounder

A NOAA instrument which has flown on NOAA satellites since 1978. Instrument has 19 channels between 3 and 15 micrometers, and 1 channel at 0.7 micrometers wavelength. Spatial resolution is 17 km at nadir to 58 km at 55 degrees off nadir. HIRS/3 is in orbit on the NOAA-K platform, but is not yet operational.

JERS-1: Japanese Earth Remote-Sensing Satellite-1.

The first Japanese imaging radar, which is flown in conjunction with the OPtical Sensor (OPS). JERS-1 became operational 20 May 1992. The radar has a fixed incidence angle (35 degrees) which was selected for land studies, specifically geology and mineral exploration. It is an L-band (24 cm wavelength) radar with HH polarization. The spacecraft has a tape recorder, so that data can be collected for any part of the world except poleward of 81.5 degrees.

MISR: Multi-angle Imaging SpectroRadiometer

EOS instrument, planned for the AM-1 satellite platform (launch in 1998). Provides top-of-atmosphere, cloud, and surface angular reflectance functions. Nine CCD cameras fixed at nine viewing angles out to +/- 70 degrees forward and aft of nadir, including nadir, in four spectral bands centered at 0.443, 0.555, 0.67, and 0.865 micrometers.

MLS: Microwave Limb Scanner

EOS instrument, planned for the CHEM satellite platform (launch in 2002). Passive radiationally cooled microwave limb-sounding radiometer/spectrometer, with spectral bands centered at 215, 440, and 640 GHz and 2.5 THz, with a spectral resolution of 1 MHz. A similar instrument was flown as part of the Upper Atmosphere Research Satellite (UARS) mission.

MODIS: Moderate-Resolution Imaging Spectroradiometer

EOS instrument planned for the AM-1 and PM-1 platforms (launches in 1998 and 2000). Imaging radiometer with 36 discrete bands between 0.4 and 15 micrometers. At nadir, spatial resolution is 250 m (for two bands), 500 m (5 bands), or 1 km (29 bands).

NOAA: National Oceanographic and Atmospheric Administration

RADARSAT: Radar Satellite

A Canadian C-band (5.6 cm wavelength) imaging radar with HH polarization, which has a variable incidence angle from 20 to 50 degrees. Swath width is selectable (from about 100 km at 30 meter resolution to about 500 km at about 100 meter resolution). Data collection from this instrument began June 1996.

SAGE III: Stratospheric Aerosol and Gas Experiment III

Two nearly identical EOS instruments, one planned for Meteor-3M to be launched in 1999 and the second as an attached payload for the 51.6 degrees-inclined Space Station. Limb-scanning grating spectrometer with 1 km vertical resolution. Will be used to retrieve atmospheric profiles of aerosols, O3, H2O, NO2, NO3, OClO, O2, temperature, and pressure. Previous versions of SAGE have been flown on satellites; SAGE I (4-channel sun photometer) was launched 2/79 and collected data until 11/81, SAGE II (7-channel solar photometer) was launched 10/84.

SAR: Synthetic Aperture Radar

Side-looking imaging radar system that uses the Doppler effect to sharpen the effective resolution in the cross-track direction.

SIR-C: Shuttle Imaging Radar-C

Space Shuttle radar instrument which was flown on STS-59 in April 9-20, 1994, and on STS-68 September 30-October 11, 1994. The instrument is a cooperative experiment between NASA, the German Space Agency DARA, and the Italian Space Agency (ASI).The orbital inclination on the first flight was 57 degrees, providing coverage of volcanoes as far north as Central Kamchatka. About 20% of the Earth's land surface was imaged during the first flight of the radar. The SIR-C operates at L-band (23.5-cm wavelength) and C-band (5.8 cm), with HH, HV, VH, and VV polarization modes. The magnitude and phase information is also retained, so that the entire Stokes matrix information can be obtained. The SIR-C antenna is electronically steerable, and has the capability to view the Earth at incidence angles between 18 - 58 degrees. Resolution is typically 30 x 30 m on the surface.

TES: Tropospheric Emission Spectrometer

EOS instrument planned for the EOS-CHEM platform (launch in 2002). Pointable infrared imaging Fourier transform spectrometer with spectral coverage from 3.2 to 15.4 micrometers at a spectral resolution of 0.025 wavenumber in limb-scanning mode and 0.1 wavenumber in down-looking modes (nadir to 45 degrees off nadir). In down- looking modes, spatial resolution is 50 x 5 km or 5 x 0.5 km, In limb mode, vertical resolution is 2.3 km, with coverage from 0 to 33 km altitude.

TIMS: Thermal Infrared Multispectral Scanner

A NASA aircraft instrument with 6 channels covering the 8-12 micrometer wavelength range, first flown in 1981. The digitized field of view contains 638 pixels with a total field of view of 76.5 degrees. Ground resolution from a 3000 m altitude is 7.6 m. The instrument has its own blackbody calibration sources.

TOMS: Total Ozone Mapping Spectrometer

A NASA instrument which has flown on the NIMBUS-7 platform (operating 1978-1993), the Russian Meteor-3 satellite (1991-1994), Japanese ADEOS satellite (1996-1997), and is currently flying on its own satellite platform: Earth Probe TOMS (1996-to present). The TOMS instruments are monochromators with approximately 1 nm bandpass channels at six ultraviolet wavelengths. Spatial resolution of Earth Probe TOMS is 39 x 39 km at nadir. This instrument is used to measure total column amounts of ozone by measuring the backscattered ultraviolet sunlight and direct irradiance. Two channels are sensitive to SO2 absorption, allowing retrievals of SO2 column abundance. The column abundance of volcanic ash can also be retrieved.

TOPSAR: Topographic Synthetic Aperture Radar

A NASA aircraft interferometric radar sensor (C-band, 5.3 cm wavelength, VV polarization). Resolution of digital elevation models produced from TOPSAR is approximately 10 m horizontal, 2 m vertical.

X-SAR: X-Band Synthetic Aperture Radar

A radar instrument flown with SIR-C on the Space Shuttle STS-59 in April, 1994, and on STS-68 in September-October, 1994. X-SAR operates at X-band (3.1 cm wavelength) with VV polarization. The antenna is mechanically steerable through the range of incidence angles of SIR-C (18 - 58 degrees).

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