Total solar irradiance as measured by the SOVAP radiometer onboard PICARD

Mustapha Meftah (1) , André Chevalier (2) , Christian Conscience (2) , Stijn Nevens (2)

1 STRATO - LATMOS
2 IRM - Institut Royal Météorologique de Belgique [Bruxelles] - Royal Meteorological Institute of Belgium

From the SOlar VAriability PICARD (SOVAP) space-based radiometer, we obtained a new time series of the total solar irradiance (TSI) during Solar Cycle 24. Based on SOVAP data, we obtained that the TSI input at the top of the Earth’s atmosphere at a distance of one astronomical unit from the Sun is 1361.8 ± 2.4 W m^-2 (1σ) representative of the 2008 solar minimum period. From 2010 to 2014, the amplitude of the changes has been of the order of ± 0.1%, corresponding to a range of about 2.7 W m^-2. To determine the TSI from SOVAP, we present here an improved instrument equation. A parameter was integrated from a theoretical analysis that highlighted the thermo-electrical non-equivalence of the radiometric cavity. From this approach, we obtained values that are lower than those previously provided with the same type of instrument. The results in this paper supersede the previous SOVAP analysis and provide the best SOVAP-based TSI-value estimate and its temporal variation.

Mots clés: Sun; Total Irradiance; Solar activity; Solar Cycle; Spacecraf

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]; Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]

Mustapha Meftah, André Chevalier, Christian Conscience, Stijn Nevens. Total solar irradiance as measured by the SOVAP radiometer onboard PICARD. Journal of Space Weather and Space Climate, 2016, 6, pp.A34. ⟨10.1051/swsc/2016027⟩. ⟨insu-01356960⟩