ERS (European Resource Sensing)
The ESA (European Space Agency) ERS satellites’
main mission was to observe Earth, in particular its atmosphere
and ocean, through radar techniques. ERS 1 was retired in 2000 and
ERS 2 in 2011. ERS 2, which was originally designed to last 3 years,
continued to provide its harvest of data for 16 years. ERS 2 carried
on board the same sensors as ERS 1. The best known of which is the
Synthetic Aperture Radar (SAR) sensor, which was the first commercial
radar sensor. ERS 2 was equipped with an additional instrument (GOME),
which allows the monitoring of atmospheric ozone.
altitude: 785 km
inclination: 98.52 degrees
orbit: sun-synchronous polar
orbit period: 100 minutes
rvisit time: 3 days
swath width: 5 – 100 km (AMI) - 500 km (ATSR)
|| (17/07/1991 - 10/03/2000)
||(21/04/1995 - 4/07/2011)
AMI (Active Microwave Instrument)
This instrument consists of two different
radar systems, namely, a SAR, which can work in image mode or wave
mode (in the latter case it measures wave heights), and a wind scatterometer,
which is a radar system to measure wind speeds and direction on
the seas surface. The very great control over their orbits
(the satellites positions are known with great precision by
means of two onboard instruments) and possibility of using two identical
SARs have made ERS satellites ideal for interferometric studies.
AMI-SAR: SARimage mode
Spectral band: C band (5.3 GHz)
Resolution: variable, approx. 20m x 15.8m
RA (Radar Altimeter)
This radar altimeter works in the K band (13.8 GHz) and measures
altitude vertical to the satellite with a maximum resolution of
10 m. It has two measuring modes, the ocean mode (which measures
wave height, the altitude of the oceans surface, and surface
wind speed), and ice mode (which gives information on the topography
of the surfaces of the worlds ice-covered regions, the type
of ice, and sea/ice boundaries).
ATSR (Along-Track Scanning
This optical sensor works in the infrared band and is used
to measure sea-surface temperatures (SSTs) and cloud-top temperatures.
The version that was on board ERS-1 had four bands, whereas ERS-2s
ATSR comprised seven bands (the three added bands work in the visible
light spectrum). At the same time, another radar instrument, the
microwave radiometer or MWR, working in two K bands (23.8 and 36.5
GHz), measures the water vapour content of the atmosphere. This
increases the accuracy of the sea-surface temperature and altitude
(RA sensor) measurements.
GOME(Global Ozone Monitoring
This sensor, which was on board the
ERS-2 only, is a double spectrometer used to study the atmosphere.
It can study the ozone concentration as well as detecting other
gases, aerosols, and microparticles.
Spectral band: 0.240.79 µm
Resolution: 40km x 40km max. (horizontal) - 1 km (vertical)
ERS technical site
years of ERS: celebration
Access to data : ESA Earth Online Data Access