Quaternary Environments Climate and Climatic Variation

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Quaternary EnvironmentsClimate and Climatic
Variation
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Geologic Time Scale
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Glacial Time Scales in the Northern Hemisphere
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Blytt-Sernander Scheme of European Peat
Stratigraphy
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Scale of Variation
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The Climate System

• End-product of
• Atmosphere
• Oceans
• Biosphere
• Land surface
• Cryosphere

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Major Components of the Climate System
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Atmosphere

• Clouds
• Atmospheric circulation
• Greenhouse gasses (Water, Carbon Dioxide,
  Methane, Nitrous Oxides)
• Temperature
• Incoming solar radiation (INSOLATION)

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Insolation (W/m2)
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Oceans

• Thermohaline Circulation
• Thermal Inertia
• Source of Moisture
• Sea Level Rise
• Melting of ice sheets
• Thermal expansion

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Thermohaline Circulation
(Schmitz 1995)
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Cross Section of Thermohaline Circulation
(Brown et al. 1989)
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Biosphere

• Vegetation Effects on Climate
• Albedo
• Roughness
• Evapotranspiration
• Atmospheric composition
• Vegetation Response to Climate
• Faunal Response to Climate

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CO2 Sequestration
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Land Surface

• Effects of Land Surface on the Climate System
• Aspect
• Elevation
• Albedo
• Response to the Climate System
• River systems
• Sea level change
• Glacial evidence

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Cryosphere

• Ice Extent
• Albedo
• Feedback Effects
• Temperature Control

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Energy Balance in the Atmosphere

• Sensitive heat flux (H)
• Latent heat flux (LE)
• Bowen Ratio (H/LE)

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Energy Balance
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Time Scales of Climatic Variation

• Climate Varies on All Time Scales
• Driving Processes

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Climate Variation Over Multiple Scales
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Variations of the Earths Orbital Parameters

• James Croll Scottish natural historian 1867
• Milankovitch Elaborated on Crolls original
  hypothesis in 1941
• Berger Advances Milankovitchs work in the late
  1970s

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Milankovitch Cycles

• Eccentricity 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.

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Orbital Factors
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Wobble on the Earths Axis
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Precession
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Insolation and 18O
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Long Term Solar Radiation
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http//www-istp.gsfc.nasa.gov/Education/Intro.html
Illustration by Steele Hill
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