Reconstruction of Magnetic Activity of the Sun and Changes in Its Irradiance on a Millennium Timescale Using Neurocomputing

Abstract

Relations between basic indices of the Sun and the cosmogenic isotope 14 C and 10 Be records were derived using the Artificial Neural Network (ANN) technique. A reconstruction of the sunspot indices and changes in Total Solar Irradiance (TSI) was carried out. Long-term changes in TSI appear in the amplitude modulation of its 11-year cyclic variation as well as in its lower envelope describing variability of the background irradiance of the Sun. According to the reconstruction the irradiance has increased about 2.5 W m −2 since 1441.