Reconstruction of the long term variations of the total solar irradiance from geomagnetic data

Abstract

The total solar irradiance (TSI) is considered one of the main factors determining the terrestrial climate, and its variations are included in many numerical models evaluating the effects of natural as compared to anthropogenic factors of climate change. For the purposes of climate change, it is important to estimate both past and future TSI variations, which are caused by variations of the solar magnetic fields. Various proxies are used for reconstructing the long term evolution of TSI, which have some inevitable limitations leading to big uncertainties. We suggest an independent proxy-geomagnetic activity records, and present a reconstruction of TSI which supports higher long term TSI variability than generally accepted, and a prediction for a decrease in TSI in the following cycles, which can be taken into account in models of the expected future climate variability.