Efectos Del Sol En La Vida Terrestre

S. M. Yousef / ICEHM2000, Cairo University, Egypt, September, 2000, page 267- 293

THE SOLAR WOLF-GLEISSBERG CYCLE AND ITS INFLUENCE ON THE EARTH Shahinaz M. Yousef Astronomy &Meteorology Dept. Faculty of Science -Cairo University
ABSTRACT- The only continuous solar observations that extend over the important climatic time scale of decades to centuries are those of sunspots, yielding a measureof magnetic activity. There are evidences for the modulation of the amplitude of the 11 year solar cycle in a period of about 80 years known as Wolf-Gleissberg cycle. The Cycle seems to be fairly clear in the sunspot record and in its proxy measurements by cosmogenic isotopes. The cycle appears to show up in many meteorological parameters, suggesting that there may be an important sun/climateconnection over long periods of time(Hoyt and Schatten 1997). The Solar Wolf-Gleissberg cycle stimulate solar forcing on terrestrial phenomena's as evident from the pattern of Global temperature (both air and ocean temperatures). Solar Wolf- Gleissberg periodicity is marked in a wide range of terrestrial evidences since millions of years and is still at work. It is found that climatic fluctuationsare induced at the turning points of such cycles. In order to solve this problem, it is found that there are three types of solar cycles occurring on the sun namely, those occurring during Maunder minimum anomalies that caused the very cold weather in the little ice age (1645-1715), normal sunspots and low amplitude (weak sunspots of longer duration) occurring in the shallow dip in betweensuccessive Wolf- Gleissberg cycles. The later ones also induce cooling of the air and sea surface temperatures. The key in understanding the cause and effect of those types of solar cycles lies in the fact that those low amplitude intermediate cycles rotate faster than the normal ones thus . Hoyt and Schatten (1997) argue that any change in solar rotation rate is a very persuasive indicator that the deeperlevels of convection are varying, and hence there is a corresponding variation in solar luminosity and irradiance. Also there has been evidence of change of the daily equatorial rates and cycle length at the maximum of the last Solar Wolf-Gleissberg cycle around cycle 19. Climate fluctuations are known from, sharp rises or falls of lakes levels, temperature anomalies, change in the general windcirculation and droughts and flood- Hazards. Yousef(1995a) predicted the downturn of solar activity in 1997 with the start of weak low amplitude fast rotation and longer duration sunspot cycle 23. This is evidently confirmed by the sharp rise of lake Victoria level in 1997-98. Lean (2001) is also seeing a drop in the solar irradiance which might be the start of a longer term drop. Since that is thecase, then 1997 is a year of climate fluctuation and a drop of global earth air and sea temperature is predicted soon similar to that happened during similar circumstances around 1800 and 1900, with increased El Nino and La Nina frequencies leading to wide spread flood -drought hazards and God knows best.

1-INTRODUCTION
“A growing mass of evidence suggests that transient events on the sunaffect our weather and long term variations of the sun’s energy output affect our climate. Solar terrestrial exploration can help establishes the physical cause and effect relationships between solar stimuli and terrestrial responses. When these relationships are understood, science will have an essential tool for weather and climate prediction“. This paragraph was written by Robert D. Chapman aspart of a proposal for a five-year plan for Solar Terrestrial Programs in the National Aeronautics and Space Administration(Herman and Goldberg 1978). . M. Yousef / ICEHM2000, Cairo University, Egypt, September, 2000, page 266- 292 S The subject of Sun-weather relationships is built on correlations between changes in solar activity and changes in terrestrial weather and climate. Several books and...