Solar Variation and Global Climate Change

The Sun continually radiates electromagnetic wave and particles to Earth, and the solar radiation is the main energy resource for the Earth’s climate system. The response of climate system to the solar variation is very complex, including radiative process, dynamic process and microphysics process. This paper reviews the measurements from satellites and reconstruction results by other proxies of the solar irradiance variation, enumerates some climate observational evidence in the fields of paleoclimate, temperature, atmospheric circulations and clouds affected by the solar activity. The three main possible mechanisms by which the solar variation may influence the global climate include: the variability of total solar irradiance could change the earth surface temperature, and thus change the atmospheric circulation via the ocean-atmosphere couple; the solar ultra violet radiations modulate the stratospheric temperature and wind field by heating ozone, and the stratosphere response could then affect the lower troposphere by stratosphere troposphere coupling; the solar modulates galactic cosmic ray through interplanetary magnetic field, and galactic cosmic ray may change the cloud cover via ionizing the atmosphere, which could further change the earth’s energy budget.