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Studying solar variability and its possible effects on Earth's climate

There are already many satellites observing the Sun. Missions such as Cluster, Double Star, SOHO and STEREO are investigating the solar wind, solar flares and radiation, magnetic field, as well as the Sun’s structure and composition. In a context of considerable change to the Earth’s climate, Picard complemented these missions to help scientists explain the links between solar cycles and changing of temperatures on Earth.

Picard microsatellite sent back data needed to improve models used for forecasting solar activity. It was designed to take simultaneous measurements of such parameters as the speed at which the Sun rotates, the radiation it emits, the presence of sunspots and its shape and diameter, to help scientists understand the relationship between them. These models also help to evaluate the influence of the Sun on the dynamic chemical processes governing balances in Earth’s atmosphere.

To predict how the Sun may influence the Earth in the future, scientists need to study the past and Picard has helped here, too, by investigating the relationship between changes in solar activity and certain climate events here on Earth. Why did mean temperatures drop during the 17th century, known as the Maunder minimum (1645-1715)? Did a ‘slow-down’ on the Sun cause cooling on Earth? Very few clues remain about this period and the only scientific evidence is a series of measurements of the solar diameter by the French astronomer, Jean Picard, after whom the satellite was named. It is important to establish to what extent this parameter correlates with solar activity. The Picard satellite has helped to solve this question by providing data for models able to reconstruct the climate of this period and comparing simulations with actual observations.

The other objectives of the Picard programme were to study the Sun’s internal structure using helioseismology techniques and to analyse the impact of solar variability on the processes governing balances in Earth’s atmosphere, notably the relationship between solar ultraviolet radiation and stratospheric ozone.

CNES developed the Picard system, particularly the satellite, which it is also operating. The LATMOS atmospheres, environments and space observations laboratory at CNRS was prime contractor for development of the payload and specifically the SODISM instrument. The two other instruments, PREMOS and SOVAP, were developed respectively under the responsibility of Swiss Space Office and the Belgian Federal Science Policy Office.

Picard microsatellite
Initiator CNES
Participants CNES, CNRS, Swiss Space Office, Belgian Federal Science Policy Office
Objectives To characterise variations in solar activity
To study the influence of solar activity on the climate
To detect solar events
To study the Sun’s internal structure
To study the Sun’s effect on atmospheric ozone
Status Mission completed
Launch 15 June 2010 on DNEPR launcher

Last updated : July 2013.

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