Book contents
- Frontmatter
- Contents
- Preface
- 1 Interconnectedness in heliophysics
- 2 Long-term evolution of magnetic activity of Sun-like stars
- 3 Formation and early evolution of stars and protoplanetary disks
- 4 Planetary habitability on astronomical time scales
- 5 Solar internal flows and dynamo action
- 6 Modeling solar and stellar dynamos
- 7 Planetary fields and dynamos
- 8 The structure and evolution of the three-dimensional solar wind
- 9 The heliosphere and cosmic rays
- 10 Solar spectral irradiance: measurements and models
- 11 Astrophysical influences on planetary climate systems
- 12 Assessing the Sun–climate relationship in paleoclimate records
- 13 Terrestrial ionospheres
- 14 Long-term evolution of the geospace climate
- 15 Waves and transport processes in atmospheres and oceans
- 16 Solar variability, climate, and atmospheric photochemistry
- Appendix I Authors and editors
- List of illustrations
- List of tables
- References
- Index
- Plates
16 - Solar variability, climate, and atmospheric photochemistry
Published online by Cambridge University Press: 05 April 2013
- Frontmatter
- Contents
- Preface
- 1 Interconnectedness in heliophysics
- 2 Long-term evolution of magnetic activity of Sun-like stars
- 3 Formation and early evolution of stars and protoplanetary disks
- 4 Planetary habitability on astronomical time scales
- 5 Solar internal flows and dynamo action
- 6 Modeling solar and stellar dynamos
- 7 Planetary fields and dynamos
- 8 The structure and evolution of the three-dimensional solar wind
- 9 The heliosphere and cosmic rays
- 10 Solar spectral irradiance: measurements and models
- 11 Astrophysical influences on planetary climate systems
- 12 Assessing the Sun–climate relationship in paleoclimate records
- 13 Terrestrial ionospheres
- 14 Long-term evolution of the geospace climate
- 15 Waves and transport processes in atmospheres and oceans
- 16 Solar variability, climate, and atmospheric photochemistry
- Appendix I Authors and editors
- List of illustrations
- List of tables
- References
- Index
- Plates
Summary
Introduction
The possible link between solar variability and climate remains an intriguing and controversial issue. Solar physicists have shown that the total solar irradiance (S0 = L⊙/4πd2⊙), whose value is close to 1366 W m−2 (Fröhlich, 2004), varies typically by 1.5 W m−2 (slightly more than 0.1%) over an 11-year solar cycle (see Chapter 10 and Fig. 10.9). This change is considerably smaller than the radiative forcing produced by enhanced concentrations of greenhouse gases since the beginning of the industrial era. Figure 16.1 (from the Fourth Assessment conducted by the Intergovernmental Panel on Climate Change, or IPCC) highlights a possible longer term trend in the solar irradiance, but, unless some amplification mechanisms occur, this forcing remains small compared, for example, to the effect of carbon dioxide and other radiatively active gases, whose atmospheric concentrations have increased as a result of human activity.
Different mechanisms have been proposed to explain the relations between the state of the atmosphere and the 11-year solar cycle. One of them is the absorption of short-wave solar radiation by ozone in the stratosphere with possible effects on the diabatic heating, temperature, and the general circulation of the atmosphere. Another mechanism refers to the impact of galactic cosmic rays on the formation of cloud condensation nuclei and hence on cloudiness and surface temperature. The cosmic-ray intensity in the atmosphere is anti-correlated with solar activity (Chapters 9 and 11).
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- Publisher: Cambridge University PressPrint publication year: 2010