The sun and our climate

The solar irradiance which reaches our planet varies in sympathy with the eleven year activity cycle of the sun. Eleven year variations of the order of 1 W/m2 cause temperature variations of the order of 0.1 °C. During the period of low solar activity around 1700 the little ice age existed with temperatures 0.7 °C lower than during the second part of the twentieth century.

At the RMIB we build our own instruments for the measurements of the solar irradiance from space, with a first flight on Spacelab in 1983. We have a currently active DIARAD/VIRGO instrument on the SOHO satellite, this provides measurements of high quality since 1996. We are building the SOVAP instrument for launch on the French microsatellite Picard in March 2009. The SOVAP measurements will allow the reconstruction of the solar irradiance level during the little ice age. Soon our DIARAD/SOVIM instrument for the International Space Station will be launched.

Solar irradiance graph