Joanna Dorothy Haigh & Michael Lockwood 
The Sun, Solar Analogs and the Climate 
Saas-Fee Advanced Course 34, 2004. Swiss Society for Astrophysics and Astronomy

The 34th Saas-Fee advanced course of the Swiss Society of Astronomy and Astrophysics (SSAA) took place from March 15 to 20, 2004, in Davos, on the subject of The Sun, Solar Analogs and the Climate. Presentlythe Swissmountainresortof Davosisprobablymostwellknown for hosting an event on globalization. However, it is because Davos also happens to be the seat of the Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center, that this course on a “global” subject was hosted here. Exceptionally, the topic of this course was not purely astrophysical, but themembersofthe SSAAdecidedtosupportitallthesameduetothetimely topic of global warming and its possible link to solar variations. In these times of concern about global warming, it is important to und- stand solar variability and its interaction with the atmosphere. Only in this way can we distinguish between the solar and anthropogenic contributions to the rising temperatures. Therefore, this course addressed the observed va- ability of the Sun and the present understanding of the variability’s origin and its impact on the Earth’s climate. Comparing the solar variability with that of solar analog stars leads to a better understanding of the solar activity cycle and magnetic activity in general, and helps us to estimate how large the solar variations could be on longer time scales. Inspiteofthefantasticweatherandsnowconditionswhichreignedduring this week, the participants assiduously took part in the lectures. This is proof ofthehighqualityofthelecturesthatthethreespeakers, Joanna Haigh, Mike Lockwood and David Soderblom, delivered. We deeply thank them for their contributions and e?orts and hope that the readers will enjoy the book as much as we enjoyed their lectures.

Table of Content

The Earth’s Climate and its Response to Solar Variability: The Climate System.- Atmospheric Dynamics, Modes of Variability and Climate Modelling.- Climate Records.- Radiative Processes in the Atmosphere.- The Greenhouse Effect and Radiative Forcing of Climate Change.- Clouds.- Atmospheric Photochemistry.- Response of Climate to Variations in Solar Irradiance.- The Earth’s Electric Field and Ionisation of the Atmosphere.- Conclusions.- Solar Outputs, Their Variations and Their Effects on Earth: Introduction to the Sun and the Solar Activity Cycle.- Fundamental Plasma Physics of the Sun and Heliosphere.- The Heliosphere, Cosmic Rays and Cosmogenic Isotopes.- Solar Irradiance Variations.- Variability on Century Timescales.- Implications for Earth’s Climate.- Conclusions and Implications.- Stellar Analogs of Solar Activity: The Sun in A Stellar Context: Introduction.- Stellar Cycles.- Brightness Changes in Solar-Type Stars.- Activity in Solar Analogs.- Stellar Surface Inhomogeneities.- The Coronae of Solar Analogs, Low Mass Stars, and Brown Dwarfs.- The Early Sun.- Stellar Activity and Extrasolar Planets.- Index.