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J. Noll
A.2 Research oriented missions, ENVISAT
ENVISAT, the follow-on to ERS-1 and ERS-2, will cater the future needs of the international
community of both science- and operational application of remote sensing data. ENVISAT
will continue and improve meteorological observations such as 'greenhouse effects', acid rain,
depletion of the ozone layer, and improve observations for ocean, sea ice and land applications,
study the Earth structure and the dynamics of the Earth's crust and interior.
A.2.1 Mission overview
Scheduled to be launched at the end of 1998, ENVISAT will collect remote sensing data, which
in combination with retrieval algorithms will allow the observation of geophysical parameters
for the atmosphere, land, ocean and the cryosphere (Readings et ai, 1993). ENVISAT will
operate in a polar sun synchronous orbit at 98.55° at an altitude of 800 km, leading to 14¥sorbits/day with an orbit cycle of 100.6 min.
A.2.2 Instrumentation of ENVISAT
ENVISAT will carry eleven instruments (Table A-2), which will allow in the first place to
monitor geophysical parameters on land, ocean, cryosphere and the atmosphere (Table A-3).
AATSR
ASAR
DORIS
GOMOS
LRR
MERIS
MIPAS
MWR
RA-2
SCARAB
SCIAMACH
Advanced Along Track Scanning Radiometer
Advanced Synthetic Aperture Radar
Optical/IR radiometer
C-band SAR
Doppler Orbitography and Radiopositioning In- RF Orbitography
tegrated by Satellite
Global Ozone Monitoring by Occultation of UV /Optical spectrometer
Stars
Laser Retro Reflector
Medium Resolution Imaging Spectrometer
Michelson Interferometer for Passive Atmospheric Sounding
Microwave Radiometer
Radar Altimeter
Scanner for Radiation Budget
Scanning Imaging absorptance spectrometer for
Atmospheric Cartography
Passive Optical Reflector
VIS/near IR Spectrometer
Limb-view IR Interferometer
Two-Channel Nadir View
Radiometer
Pulse Radar
4 chan. VIS/IR radiometer
Nadir + Limb UV /VIS/IR
spectrometer
Table A-2: ENVISAT-1 instruments (Readings et al., 1993) (the highlighted instruments are
sensors operating in the microwaves).
As monitoring of the ecosystem requires detailed knowledge of not only the environmental
characteristics, but also of the associated physical/biological processes, the instruments on ENVISAT are selected in order to be complementary. For land surfaces it is expected that the
payload will provide the data to allow the estimation of surface albedos, vegetation cover, vegetation characteristics, etc. All of these data correlate with the surface energy and water budgets
and the transfer of trace species between the land surface and the atmosphere. In detail, the
AATSR is foreseen to measure the land surface temperature and the vegetation characteristics,
J. Noll
A.2 Research oriented missions, ENVISAT
ENVISAT, the follow-on to ERS-1 and ERS-2, will cater the future needs of the international
community of both science- and operational application of remote sensing data. ENVISAT
will continue and improve meteorological observations such as 'greenhouse effects', acid rain,
depletion of the ozone layer, and improve observations for ocean, sea ice and land applications,
study the Earth structure and the dynamics of the Earth's crust and interior.
A.2.1 Mission overview
Scheduled to be launched at the end of 1998, ENVISAT will collect remote sensing data, which
in combination with retrieval algorithms will allow the observation of geophysical parameters
for the atmosphere, land, ocean and the cryosphere (Readings et ai, 1993). ENVISAT will
operate in a polar sun synchronous orbit at 98.55° at an altitude of 800 km, leading to 14¥sorbits/day with an orbit cycle of 100.6 min.
A.2.2 Instrumentation of ENVISAT
ENVISAT will carry eleven instruments (Table A-2), which will allow in the first place to
monitor geophysical parameters on land, ocean, cryosphere and the atmosphere (Table A-3).
AATSR
ASAR
DORIS
GOMOS
LRR
MERIS
MIPAS
MWR
RA-2
SCARAB
SCIAMACH
Advanced Along Track Scanning Radiometer
Advanced Synthetic Aperture Radar
Optical/IR radiometer
C-band SAR
Doppler Orbitography and Radiopositioning In- RF Orbitography
tegrated by Satellite
Global Ozone Monitoring by Occultation of UV /Optical spectrometer
Stars
Laser Retro Reflector
Medium Resolution Imaging Spectrometer
Michelson Interferometer for Passive Atmospheric Sounding
Microwave Radiometer
Radar Altimeter
Scanner for Radiation Budget
Scanning Imaging absorptance spectrometer for
Atmospheric Cartography
Passive Optical Reflector
VIS/near IR Spectrometer
Limb-view IR Interferometer
Two-Channel Nadir View
Radiometer
Pulse Radar
4 chan. VIS/IR radiometer
Nadir + Limb UV /VIS/IR
spectrometer
Table A-2: ENVISAT-1 instruments (Readings et al., 1993) (the highlighted instruments are
sensors operating in the microwaves).
As monitoring of the ecosystem requires detailed knowledge of not only the environmental
characteristics, but also of the associated physical/biological processes, the instruments on ENVISAT are selected in order to be complementary. For land surfaces it is expected that the
payload will provide the data to allow the estimation of surface albedos, vegetation cover, vegetation characteristics, etc. All of these data correlate with the surface energy and water budgets
and the transfer of trace species between the land surface and the atmosphere. In detail, the
AATSR is foreseen to measure the land surface temperature and the vegetation characteristics,