Solar Effects on Weather and Climate in the Indonesian Archipelago
The Houw Liong1)
Plato Martuani Siregar2)
1)Departemen Fisika, FMIPA-ITB
2)Departemen GM , FIKTM-ITB
3)Departemen Astronomi, FMIPA-ITB
From various stations at Geographic Latitudes from 60N to 100S throughout the Indonesian Archipelago, anomalies of Rainfall and Irradiance were collected and plotted to those of the Monthly Sunspot Number between 1948 and 2003. It is shown that there is a tight correlation between solar activity and the various geophysical variables, such as the mean temperature of Earth, the cloud cover, the sea surface temperature and the rainfall throughout the region. It is also found that there is a weak correlation between the coefficients of correlation obtained from various plots of the Number of Sunspot to Irradiance, the Irradiance to Rainfall and The Number of Sunspot to Rainfall from each station against the Geomagnetic Latitude of the stations. The coefficients of correlations increase as we go to higher Geomagnetic Latitudes. The ability of cosmic ray particles to penetrate is limited by the earth’s magnetic field. In addition during solar activity the magnetic field of the solar wind increases and diminishes strongly the flux of cosmic rays. The earth’s magnetic field forms a shield against charged particles everywhere except for those entering around the magnetic poles. Fields near the equator are very efficient in shielding cosmic ray penetration, because it is parallel to the earth’s surface. At higher latitudes it will be less shielded, because the fields are more vertical. If it is true that a correlation exist between cosmic rays, formation of clouds and climate as some researchers suggest, than, this may well explain the marked increase of the coefficients of correlations, thus the stronger dependency of the events at higher magnetic latitudes.
This research shows that the knowledge of solar activity can be used to predict extreme weather in Indonesia.
This is the initial study at ITB to embark and promote researches on Solar Effects on Weather and Climate in the Indonesian Archipelago.
Keywords: solar cycle, geomagnetic effects, solar activity, extreme weather.