[First Hit]

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Alfred H. Pekarek1
(1) St. Cloud State University, St. Cloud, MN

Abstract: Previous HitSolarNext Hit forcing of Earth's climate

The sun is the primary source of Previous HitenergyNext Hit for the climate of the earth. Variations in Previous HitsolarNext Hit Previous HitenergyNext Hit reaching the earth's surface change the climate. Several factors control the influx of Previous HitsolarNext Hit Previous HitenergyNext Hit including (1) variations in the earth's albedo, (2) variations in earth's orbit and rotation, and (3) variations in Previous HitsolarNext Hit Previous HitenergyNext Hit output.

In the short time since 1978, direct measurement of total Previous HitsolarNext Hit irradiance (TSI) by satellites has shown cyclical variations in Previous HitsolarNext Hit Previous HitenergyNext Hit of 0.1% in conjunction with the eleven year sunspot cycle. Indirect evidence from the Sun and other sun-like stars indicates that TSI has had significantly greater variation as the Sun goes through various cycles.

The correlations between climate and TSI variations are statistically solid. Small variations in TSI initiate indirect mechanisms on earth that yield climate changes greater than that predicted for the TSI change alone. At least three Previous HitsolarNext Hit variables are known to affect earth's climate: (1) TSI, which directly affects temperatures; (2) Previous HitsolarNext Hit ultraviolet radiation, which affects ozone production and upper atmospheric winds; and (3) the Previous HitsolarNext Hit wind which affects rainfall and cloud cover, at least partially through control of earth's electrical field. Each affects the earth's climate in different ways, producing indirect effects that amplify small changes in TSI. Individually, they do not cause the entire observed climatic changes. Collectively, they appear sufficient especially since Previous HitsolarNext Hit forcing of earth's climate is still an emerging science. Undoubtedly, other mechanisms of Previous HitsolarTop forcing are poorly understood, perhaps even unknown.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana