EOS 10.2.07

EOS 10.2.07 - Milankovitch Cycles o Influence amount of...

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Milankovitch Cycles o Influence amount of solar radiation on earth, Especially the poles Eccentricity of earth’s orbit around sun changes from around sun changes from round to ovular over ~100,000 yr cycle (moves earth Obliquity is the earth’s angle to the sun; ranges from 22.1 degrees to 24.5 degrees in ~41,000 year of cycle Precession: the earth’s axis wobbles on a ~26,000 year cycle Solar Forcing Curve: o Combines all 3 cycles and it correlates to statges of graciation over last 3 million years Low Solar forcing ; coincides w/ glacial advancement Now that CO2 levels are relatively low true effects of the Milankovitch cycles can be seen Calculated we should enter an ice age in the next 6,000 years based on the Milankovitch cycles ut the CO2 levels in the atmosphere may override the effects of solar forcing Systems: components & subcomponents or subsystems- can be any size or scale we choose Feedbacks- (or feedback loops) o Positive- increase starting condition; ex. Cooling, ice buildup, increased albedo of surface, further cooling, ice buildup etc. Further cooling, ice buildup etc. o Negative- starting conditions moderated or reduced surface. Ex. Surface of planet warms, inc. evaporation, including lava cover, inc. cloud cover, cloud reflectivity, less incoming sun, less heating of earth’s surface **In general, + feedback easier to put into an equation than – feedback. 10/18/07 Modeling and Submodeling What is the difference between weather and climate? o Our models are very bad, its hard to predict for the future o Climate is much more broad definition of what an area will be like. Average of weather conditions of an area. o Climate models are concerned what the average mean temp will be 150 years from now, humidity? Etc. . What can we expect? Models: Ways to express the weather/weather condition mathematically
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This note was uploaded on 04/20/2008 for the course EOS 155 taught by Professor Alexanderglass during the Fall '08 term at Duke.

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EOS 10.2.07 - Milankovitch Cycles o Influence amount of...

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