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The POLDER mission |
The regular increase in greenhouse gases due to anthropogenic emissions in the atmosphere may have a major impact on the Earth's climate in the forthcoming decades. In order to reduce the uncertainties in forecasting climatic changes, it is necessary to better understand the processes involved in interactions between aerosols, clouds, radiation and atmospheric circulation. Such interactions are poorly represented by current numerical models and there is a need to quantify their role in phenomena involved in the evolution of the climate system.
Carbon dioxide uptake by the upper ocean and continental biosphere also constitutes a large element of uncertainty in climate models. Spaceborne sensors will play a key role in climate research by providing global, long term observations of parameters describing the state of the atmosphere and Earth surfaces. The French space agency, CNES, has therefore developed the POLDER (POLarization and Directionality of the Earth's Reflectances) instrument, to be flown on ADEOS (ADvanced Earth Observation Satellite), developed by the Japanese space agency, NASDA.
A second, identical instrument is to be flown on ADEOS-2, successor to ADEOS, in 1999.
It will ensure the continuity of the POLDER mission over a significantly long period from
a climate point of view.
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| The Japanese launch vehicule H2 will launch ADEOS from the Tanegashima site in August 1996 |
The ADEOS satellite in stowed configuration (3500 kg, 4x4x5 m) |
POLDER-acquired data will be processed in order to :
- determine the physical and optical properties of aerosols so as to classify them and
study their variability and cycle,
- improve the climatological description of certain physical, optical and radiative
properties of clouds,
- precisely determine the influence of aerosols and clouds on the Earth's radiation
budget,
- quantify the role of photosynthesis from the continental biosphere and oceans in the
global carbon cycle.
The scientific results from POLDER will contribute to the World Climate Research Programme and the International Geosphere-Biosphere Programme.
