SOVAP/Picard, a Spaceborne Radiometer to Measure the Total Solar Irradiance (original) (raw)

The Picard spacecraft was successfully launched on June 15, 2010, into a Sun synchronous orbit. The mission represents one of the European contributions to solar observations and Essential Climate Variables (ECVs) measurements. The payload is composed of a Solar Diameter Imager and Surface Mapper (SODISM) and two radiometers: SOlar VAriability Picard (SOVAP) and PREcision MOnitor Sensor (PREMOS). SOVAP, a dual side-by-side cavity radiometer, measures the total solar irradiance (TSI). It is the sixth of a series of differential absolute radiometer type instruments developed and operated in space by the Royal Meteorological Institute of Belgium. The measurements of SOVAP in the summer of 2010, yielded a TSI value of 1362.1 W.m −2 with an uncertainty of ±2.4 W.m −2 (k=1 ). During the periods of November 2010 and January 2013, the amplitude of the changes in TSI has been of the order of 0.18%, corresponding to a range of about 2.4 W.m −2 .