Quaternary Environments Climate and Climatic Variation

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  • Quaternary EnvironmentsClimate and Climatic Variation

  • Geologic Time Scale

  • Glacial Time Scales in the Northern Hemisphere

  • Blytt-Sernander Scheme of European Peat Stratigraphy

  • Scale of Variation

  • The Climate SystemEnd-product ofAtmosphereOceansBiosphereLand surfaceCryosphere

  • Major Components of the Climate System

  • AtmosphereCloudsAtmospheric circulationGreenhouse gasses (Water, Carbon Dioxide, Methane, Nitrous Oxides)TemperatureIncoming solar radiation (INSOLATION)

  • Insolation (W/m2)

  • OceansThermohaline CirculationThermal InertiaSource of MoistureSea Level RiseMelting of ice sheetsThermal expansion

  • Thermohaline Circulation(Schmitz 1995)

  • Cross Section of Thermohaline Circulation(Brown et al. 1989)

  • BiosphereVegetation Effects on ClimateAlbedoRoughnessEvapotranspirationAtmospheric compositionVegetation Response to ClimateFaunal Response to Climate

  • CO2 Sequestration

  • Land SurfaceEffects of Land Surface on the Climate SystemAspectElevationAlbedoResponse to the Climate SystemRiver systemsSea level changeGlacial evidence

  • CryosphereIce ExtentAlbedoFeedback EffectsTemperature Control

  • Energy Balance in the AtmosphereSensitive heat flux (H)Latent heat flux (LE)Bowen Ratio (H/LE)

  • Energy Balance

  • Time Scales of Climatic VariationClimate Varies on All Time ScalesDriving Processes

  • Climate Variation Over Multiple Scales

  • Variations of the Earths Orbital ParametersJames Croll; Scottish natural historian 1867Milankovitch; Elaborated on Crolls original hypothesis in 1941Berger; Advances Milankovitchs work in the late 1970s

  • Milankovitch CyclesEccentricity 95,800 year period. Changes in the orbital path of the Earth around the Sun. Affects the relative intensities of the seasons.Obliquity 41,000 year period. Changes in axial tilt of the Earth.Precession 21,700 year period. Wobble of the axis causing a precession of the equinoxes. Perihelion during Northern Hemisphere summer occurred 11,000 years ago.

  • Orbital Factors

  • Wobble on the Earths Axis

  • Precession

  • Insolation and 18O

  • Long Term Solar Radiation

  • http://www-istp.gsfc.nasa.gov/Education/Intro.html; Illustration by Steele Hill