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Click on instruments for further
details
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MERIS
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The MEdium Resolution Imaging Specrometer Instrument
MERIS is a 68.5 o field-of-view
pushbroom imaging spectrometer that measures the solar
radiation reflected by the Earth, at a ground spatial
resolution of 300m, in 15 spectral bands, programmable
in width and position, in the visible and near infra-red.
MERIS allows global coverage of the Earth in 3 days.
The primary mission of MERIS is the measurement of sea
colour in the oceans and in coastal areas. Knowledge of
the sea colour can be converted into a measurement of
chlorophyll pigment concentration, suspended sediment
concentration and of aerosol loads over the marine domain.
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ASAR |
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An Advanced Synthetic Aperture Radar
Operating at C-band, ASAR ensures
continuity with the image mode (SAR) and the wave mode
of the ERS-1/2 AMI. It features enhanced capability in
terms of coverage, range of incidence angles, polarisation,
and modes of operation.
This enhanced capability is provided by significant differences
in the instrument design: a full active array antenna
equipped with distributed transmit/receive modules which
provides distinct transmit and receive beams, a digital
waveform generation for pulse "chirp" generation, a block
adaptive quantisation scheme, and a ScanSAR mode of operation
by beam scanning in elevation.
The measurement principle of ASAR depends on the use of
coherent radiation, together with precise knowledge of
the transmit and receive point of the radar pulse.
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GOMOS
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Global
Ozone Monitoring by Occultation of Stars
During the last decades it has become
increasingly apparent that the chemical composition of
the atmosphere is changing on a global scale, and that
human activity is partly responsible for this change.
Ozone plays a central role in the atmospheric chemistry.
It is largely responsible for stratospheric heating through
absorption of harmful UV radiation, it determines to a
large
extent the oxidative capacity of the troposphere and is
an important "greenhouse" gas. The discovery of the "ozone
hole" over the Antarctic has also drawn attention to the
global ozone budget. |
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AATSR |
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The prime scientific objective of the Advanced Along
Track Scanning Radiometer
Is to establish continuity
of the ATSR-1 and ATSR-2 data sets of precise sea surface
temperature (SST), thereby ensuring the production of
a unique 10 year near-continuous data set at the levels
of accuracy required (0.3 K or better) for climate research.
The second objective is to develop and exploit the science
of quantitative remote-sensing of land surfaces, particularly
vegetation, through the use of the improved visible-wavelength
atmospheric correction that will be achievable with AATSR's
two-angle view. The land and cloud measurement objectives
will be met through the use of an additional visible focal
plane assembly, which will lead to indications of vegetation
biomass; vegetation moisture; vegetation health and growth
stage.
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RA-2
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The Radar Altimeter 2
Is an instrument for determining the two-way delay of
the radar echo from the Earth's surface to a very high
precision: less than a nanosecond. It also measures the
power and the shape of the reflected radar pulses.
The RA-2 is derived from the ERS-1 and 2 Radar Altimeters,
providing improved measurement performance and new capabilities.
Operating over oceans, its measurements are used to determine
the ocean topography, thus supporting the research of
ocean circulation, bathymetry and marine geoid characteristics.
Furthermore, the RA-2 is able to map and monitor sea ice,
polar ice sheets, and most land surfaces. |
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SCIAMACHY |
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The SCanning Imaging Absorption SpectroMeter for
Atmospheric CHartographY
Is an imaging
spectrometer whose primary mission objective is to perform
global measurements of trace gases in the troposphere
and in the stratosphere. The solar radiation transmitted,
backscattered and reflected from the atmosphere is recorded
at relatively high resolution (0.2 µm to 0.5 µm) over
the range 240 nm to 1700 nm, and in selected regions between
2.0 µm and 2.4 µm.
The primary scientific objective of Sciamachy is the global
measurement of various trace gases in the troposphere
and stratosphere, which are retrieved from the instrument
by observation of transmitted, backscattered, and reflected
radiation from the atmosphere in the wavelength range
between 240 nm and 2400 nm. The large-wavelength range
is also ideally suited for the determination of aerosols
and clouds.
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MIPAS
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The Michelson Interferometer
for Passive Atmospheric Sounding
Is a Fourier transform spectrometer for the measurement
of high-resolution gaseous emission spectra at the Earth's
limb. It operates in the near to mid infrared where many
of the atmospheric trace-gases playing a major role in
atmospheric chemistry have important emission features.
The objectives of MIPAS are:
Simultaneous and global measurements of geophysical parameters
in the middle atmosphere;
Stratospheric chemistry: O3, H2O, CH4, N2O, and HNO3;
and Climatology: Temperature, CH4, N2O, O3 ;
Study of chemical composition, dynamics, and radiation
budget of the middle atmosphere;
Monitoring of stratospheric O3 and CFC's. |
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MWR
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The main objective of the microwave
radiometer (MWR) is the measurement of the integrated
atmospheric water vapour column and cloud liquid water
content, as correction terms for the radar altimeter signal.
In addition, MWR measurement data are useful for the determination
of surface emissivity and soil moisture over land, for
surface energy budget investigations to support atmospheric
studies, and for ice characterization.
The Envisat MWR has evolved from the instruments previously
flown on ERS-1 and ERS-2. |
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LRR
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A laser retroreflector will be
mounted on a pillar attached to the nadir panel close
to the RA-2 antenna.
It has two functions: support-to-satellite ranging; and
RA-2 altitude calibration.
The LRR is a passive device which will be used as a reflector
by ground-based SLR stations using high-power pulsed lasers.
The operating principle is to measure on ground the time
of a round trip of laser pulses reflected from an array
of corner cubes mounted on the Earth-facing side of the
satellite. The corner cubes ensure that the laser beam
is reflected back parallel to the incident beam. The detailed
design of the cubes includes a compensation for the aberration
of the laser beam by the velocity of the satellite: the
satellite moves almost 40 metres between the emission
and reception of the laser pulse from the SLR station,
and this is compensated by slight nonparallelism of the
reflected beam. |
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DORIS
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Doppler Orbitography and Radiopositioning Integrated
by Satellite
Is a tracking system providing range-rate measurements
of signals from a dense network of ground-based beacons.
These data are precision processed on ground providing
the satellite orbit with an accuracy of the order of centimetres.
They are also processed on board to provide real time
satellite positions with an accuracy of some tens of centimeters.
In addition to enabling orbit determination, data are
provided to:
help in the understanding of the dynamics of the solid
Earth; monitor glaciers, landslides and volcanoes;
improve the modeling of the Earth gravity field and of
the ionosphere. |
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