PARIS, December 16 2004 (AFP) - The micro-satellite CNES Parasol, to be launched on Saturday by an Ariane 5 with six other passengers should allow better understanding of the climate impact of clouds and aerosols, the tiny particles suspended in the air.
For a long time, only the greenhouse gases were considered to study the phenomenon of global warming, said the CNES. But outside the greenhouse warming, aerosols and clouds, making screen as a parasol in sunlight, tend to reverse to cool the Earth-Atmosphere system.
Modeling work has shown that natural aerosols (volcanic ash or sea spray), or those created by human activity, play a crucial role in the evolution of the climate and, according to the Academy of Sciences, constitute "the greater source of uncertainty "in the climate study.
The question is to determine what is for the planet, but also globally across regions, the final balance of competition played between this umbrella effect and the greenhouse effect.
Parasol (Polarization and Anisotropy of Reflectance at the top of the atmosphere, coupled with an observation satellite into Lidar) should provide some answers. Second satellite Myriade developed by CNES, it will measure the light polarized in different directions, in order to better characterize the clouds and aerosols, other than by their spectral signature more traditional methods.
For this purpose, the satellite will carry a microwave imaging radiometer large field Polder, designed by the Laboratory of Atmospheric Optics contribution Lille (CNRS-USTL).
The information provided will specify the amount and size distribution of aerosols over the ocean and their turbidity index (content materials in suspension) above the Earth. They also contribute to cloud detection, determination of their thermodynamic phase of their altitude and the estimated flux reflected in the solar field. The water vapor content will also be considered.
Parasol, whose life expectancy is two years, was carried out under the project management of CNES. Its development is strongly supported those Polder program for the payload, and Demeter, first microsatellite CNES, for the platform, in order to cut costs and deadlines.
The scientific responsibility for the mission returns to CNRS Atmospheric Optics Laboratory (LOA, Lille).
Parasol will be positioned relative to the Aqua and Aura satellites (Nasa), Calipso (Nasa / Cnes), Cloudsat (NASA / Canadian Space Agency) to complete the training called "A-Train", an exceptional space observatory that will be completed in 2008 by another NASA satellite, Oco.