Abstract
It is a clear fact that the Earth's climate has been changing since the pre-industrial era, especially during the last three decades. This change is generally attributed to three main factors: greenhouse gases (GHGs), aerosols, and solar activity changes. However, these factors are not all-independent. Furthermore, contributions of the above-mentioned factors are still disputed.
We sought whether a parallelism between the solar activity variations and the changes in the Earth's climate can be established. For this, we compared the solar irradiance model data reconstructed by J. Lean to surface air temperature variations of two countries: USA and Japan. Comparison was carried out in two categories: correlations and periodicities. We utilized data from a total of 60 stations, 18 in USA and 42 in Japan. USA data range from 1900 to 1995, while Japan data range from 1900 to 1990.
Our analyses yielded a 42 per cent correlation for USA and a 79 per cent for Japan between the temperature and solar irradiance. Moreover, both data sets showed similar periodicities. Hence, our results indicate marked influence of solar activity variations on the Earth's climate.
Keywords: Solar activity; Regional climate change; Cyclic variations; Greenhouse gases; Aerosols
