29. VEGETATION: AN EARTH OBSERVATION SYSTEM TO
MONITOR THE BIOSPHERE
293
2.3
Terrestrial biosphere monitoring and modeling
The contribution of the continental biosphere to the biogeochemical
cycles (exchanges of carbon and other trace gases) and to water and energy
exchanges is one of the objectives of the development of global models.
Interaction with human activities is also one of the main points to be studied,
because the effect of human pressure on the biosphere might be one of the
means by which man is acting on climate in the long term. Biosphere
processes and land cover characterization are the basis for quantification:
estimations of land cover variables as well as the dynamics of these variables
have to be made in order to obtain a good understanding of these processes
upon which models may be built. Predictions of impact of climate change on
the biosphere and of interactions of the biosphere with the climate (either
due to natural factors or to human pressure) can only be inferred from
quantification and formalization of the mechanisms by which vegetation
cover and ecosystems are functioning. Multilevel series of models have to be
developed and linked, ranging from ground studies, local parameterization
and exchange models to regional or global dynamics and interaction models.
Remote sensing of the vegetation as shown above offers a unique tool for
these developments, providing the specification of the systems is adapted to
each particular need.
3.
VEGETATION SYSTEM DESCRIPTION
Designed to provide elaborated products for thematic studies, the overall
system is based on two major components: the payload onboard the satellites
and a ground segment which archives the data, process images to generate
products and distribute them to various users. Detailed description and
updates on the quality of the system and products can be found at the URL:
http://www-vegetation.cst.cnes.fr:8050/ (Saint et al.,
1998).
3.1
The payload
It is composed of a wide field of view instrument which allows a
coverage on the Earth surface of 2250 kilometers, a solid state memory to
store about 90 minutes of acquisition, image telemetry systems and an
onboard calibration device to monitor radiometric performance of the
instrument.
MONITOR THE BIOSPHERE
293
2.3
Terrestrial biosphere monitoring and modeling
The contribution of the continental biosphere to the biogeochemical
cycles (exchanges of carbon and other trace gases) and to water and energy
exchanges is one of the objectives of the development of global models.
Interaction with human activities is also one of the main points to be studied,
because the effect of human pressure on the biosphere might be one of the
means by which man is acting on climate in the long term. Biosphere
processes and land cover characterization are the basis for quantification:
estimations of land cover variables as well as the dynamics of these variables
have to be made in order to obtain a good understanding of these processes
upon which models may be built. Predictions of impact of climate change on
the biosphere and of interactions of the biosphere with the climate (either
due to natural factors or to human pressure) can only be inferred from
quantification and formalization of the mechanisms by which vegetation
cover and ecosystems are functioning. Multilevel series of models have to be
developed and linked, ranging from ground studies, local parameterization
and exchange models to regional or global dynamics and interaction models.
Remote sensing of the vegetation as shown above offers a unique tool for
these developments, providing the specification of the systems is adapted to
each particular need.
3.
VEGETATION SYSTEM DESCRIPTION
Designed to provide elaborated products for thematic studies, the overall
system is based on two major components: the payload onboard the satellites
and a ground segment which archives the data, process images to generate
products and distribute them to various users. Detailed description and
updates on the quality of the system and products can be found at the URL:
http://www-vegetation.cst.cnes.fr:8050/ (Saint et al.,
1998).
3.1
The payload
It is composed of a wide field of view instrument which allows a
coverage on the Earth surface of 2250 kilometers, a solid state memory to
store about 90 minutes of acquisition, image telemetry systems and an
onboard calibration device to monitor radiometric performance of the
instrument.