Total Solar Irradiance: Evidence from a Long-Memory Model

This paper analyses aggregated data (5 days period) on total solar irradiance (TSI) based on the 3D MHD numerical simulations of solar surface and atmosphere (Yeo et al., 2017), from 30 April 2010 to 8 July 2023. It improves upon earlier studies by including in the sample the most recent satellite observations and by applying fractional integration methods. These are more general than alternative ones and the most suitable to obtain evidence on the stochastic properties of the series, such as its degree of persistence, and the transitory or permanent effects of shocks. The results indicate that TSI is characterised by long-range dependence or long-memory behaviour, with an order of integration higher than 0 and smaller than 1 and evidence of non-linearities; thus, the effects of shocks are long-lived. Further, the recursive analysis indicates a changing pattern across the sample period. In terms of climate change, the key issue remains the balance between incoming solar radiation and outgoing thermal radiation.