Solar Irradiance Variability is Caused by the Magnetic Activity on the Solar Surface

TL;DR

This study presents a new model of total solar irradiance variability driven solely by surface magnetism, accurately matching observed data without calibration to the observational record.

Contribution

The paper introduces a magnetism-based model of solar irradiance variability that does not require calibration to observational data, improving understanding of solar surface effects.

Findings

Model replicates 95% of observed variability from 2010 to 2016.

Model operates independently of observational calibration.

Surface magnetism accounts for most irradiance variability over analyzed timescales.

Abstract

The variation in the radiative output of the Sun, described in terms of solar irradiance, is important to climatology. A common assumption is that solar irradiance variability is driven by its surface magnetism. Verifying this assumption has, however, been hampered by the fact that models of solar irradiance variability based on solar surface magnetism have to be calibrated to observed variability. Making use of realistic three-dimensional magnetohydrodynamic simulations of the solar atmosphere and state-of-the-art solar magnetograms from the Solar Dynamics Observatory, we present a model of total solar irradiance (TSI) that does not require any such calibration. In doing so, the modeled irradiance variability is entirely independent of the observational record. (The absolute level is calibrated to the TSI record from the Total Irradiance Monitor.) The model replicates 95% of the observed variability between April 2010 and July 2016, leaving little scope for alternative drivers of solar irradiance variability at least over the time scales examined (days to years).