![]() | Only 14 pages are availabe for public view |
Abstract It is well known that the solar radiation output changes periodically and affects the Earth and near-space environment. The Earth climate system had shown irregular changes during the second half of the 20th century, especially for the last four decades. The scientific discussions about the influence of the solar radiation on global warming are still ongoing. This change is generally attributed to three main factors: greenhouse gases (GHGs), aerosols, and solar activity changes. However, these factors are all-independent. Furthermore, contributions of the abovementioned factors are still disputed. We think that there exist a certain relation between the solar activity variations and the changes in the Earth’s climate. Accordingly, we are going to study the changes in the regional/global mean surface air temperatures and solar and geomagnetic activities represented by the geomagnetic activity aa index, the planetary equivalent amplitude (Kp) and the solar activity represented by sunspot number (Rz), in time ranging from 100 to 150 years. Chapter three represents the study of the effect of solar and geomagnetic parameters on the mean surface air temperatures (MSAT) recorded at countries which covers a wide range of geographic latitudes. We select three countries in northern hemisphere (NH) which are; USA, Russia, and India, as well as, Australia, Argentina and South Africa in southern hemisphere (SH) in order to understand the existence of solar and geomagnetic activity effect on the regional and global temperatures during a long period considered starting from 1880 up to 2010. The raw temperature data used cover 53 stations at northern hemisphere (NH) and 44 at southern hemisphere (SH) at which continuous records data were available. It is well known that the surface air temperature shows serious variations with altitude which changes between 0 and ˃850m. So, the selected stations have been classified into five classes (G1 to G5) according to their altitudes. It should be noted that the temperature behaviors on both north and south hemispheres have displayed irregular and progress changes (or increases) during the second half of the 20th century to the beginning of the 21st century, especially for the last four decades (1970-2010). |