What is the solar influence on climate? Overview of activities during CAWSES-II

Annika Seppälä,Cora E Randall,Katja Matthes,Irina A Mironova

doi:10.1186/s40645-014-0024-3

Abstract

This paper presents an overview of the main advances in the Key Questions identified by the Task Group ‘What is the Solar Influence on Climate’ by the SCOSTEP CAWSES-II science program. We go through different aspects of solar forcing from solar irradiance, including total solar irradiance (TSI) and solar spectral irradiance (SSI), to energetic particle forcing, including energetic particle precipitation (EPP) and cosmic rays (CR). Besides discussing the main advances in the timeframe 2009 to 2013, we also illustrate the proposed mechanism for climate variability for the different solar variability sources listed above. The key questions are as follows: What is the importance of spectral variations to solar influences on climate? What is the effect of energetic particle forcing on the whole atmosphere and what are the implications for climate? How well do models reproduce and predict solar irradiance and energetic particle influences on the atmosphere and climate?

Highlights

The first Task Group of the Scientific Committee on Solar-Terrestrial Physics (SCOSTEP) science program Climate and Weather of the Sun-Earth System–II (CAWSES-II), which ran from 2009 to 2013, was focused on solar influences on the Earth’s climate
The first Task Group of the SCOSTEP science program Climate and Weather of the Sun-Earth System–II (CAWSES-II), which ran from 2009 to 2013, was focused on solar influences on the Earth’s climate. This field has a long history starting from investigation of the impacts of variation in the total solar irradiance (TSI) to climate, but recently the major topics of research have extended to studies of solar spectral irradiance (SSI) variation and its impacts on the atmosphere and climate, as well as the impacts of energetic particles (including solar protons, energetic electrons from the magnetosphere and cosmic rays (CR)) on the atmosphere and the potential links to regional climate effects
During the CAWSES-II period, the major questions of focus were as follows: 1. What is the importance of spectral variations to solar influences on climate?

Summary

Introduction

The first Task Group of the SCOSTEP science program Climate and Weather of the Sun-Earth System–II (CAWSES-II), which ran from 2009 to 2013, was focused on solar influences on the Earth’s climate. Merkel et al (2011) used the Whole Atmosphere Community Climate Model (WACCM) to compare the solar ozone response to the SORCE SSI observations and the NRLSSI (Lean 2000) reconstructions and extended their focus to the mesospheric responses, whereas previous studies mainly focused on the stratosphere.

Results

Conclusion