Solar cycle variation in solar irradiance

TL;DR

This paper reviews the correlation between solar irradiance and the 11-year solar cycle, discussing measurement-model discrepancies and highlighting challenges in understanding solar variability.

Contribution

It provides an overview of solar irradiance measurements and models, emphasizing the key challenges in reconciling differences between observations and theoretical models.

Findings

Measurements show correlation with solar cycle but differ in absolute values

Models explain most trends but have discrepancies in spectral dependence

Persistent differences remain in secular variation and radiometry

Abstract

The correlation between solar irradiance and the 11-year solar activity cycle is evident in the body of measurements made from space, which extend over the past four decades. Models relating variation in solar irradiance to photospheric magnetism have made significant progress in explaining most of the apparent trends in these observations. There are, however, persistent discrepancies between different measurements and models in terms of the absolute radiometry, secular variation and the spectral dependence of the solar cycle variability. We present an overview of solar irradiance measurements and models, and discuss the key challenges in reconciling the divergence between the two.