Quaternary Environments Climate and Climatic Variation.

Quaternary EnvironmentsQuaternary EnvironmentsClimate and Climatic VariationClimate and Climatic Variation

Geologic Time ScaleGeologic Time Scale

Glacial Time Glacial Time Scales in the Scales in the Northern Northern HemisphereHemisphere

Blytt-Sernander Scheme of European Blytt-Sernander Scheme of European Peat StratigraphyPeat Stratigraphy

Scale of VariationScale of Variation

The Climate SystemThe Climate System

End-product ofEnd-product of AtmosphereAtmosphere OceansOceans BiosphereBiosphere Land surfaceLand surface CryosphereCryosphere

Major Components of the Climate Major Components of the Climate SystemSystem

AtmosphereAtmosphere

CloudsClouds Atmospheric circulationAtmospheric circulation Greenhouse gasses (Water, Carbon Greenhouse gasses (Water, Carbon

Dioxide, Methane, Nitrous Oxides)Dioxide, Methane, Nitrous Oxides) TemperatureTemperature Incoming solar radiation (INSOLATION)Incoming solar radiation (INSOLATION)

Insolation (W/mInsolation (W/m22))

OceansOceans

Thermohaline CirculationThermohaline Circulation Thermal InertiaThermal Inertia Source of MoistureSource of Moisture Sea Level RiseSea Level Rise

Melting of ice sheetsMelting of ice sheets Thermal expansionThermal expansion

Thermohaline CirculationThermohaline Circulation

(Schmitz 1995)

Cross Section of Thermohaline Cross Section of Thermohaline CirculationCirculation

(Brown et al. 1989)

BiosphereBiosphere

Vegetation Effects on ClimateVegetation Effects on Climate AlbedoAlbedo RoughnessRoughness EvapotranspirationEvapotranspiration Atmospheric compositionAtmospheric composition

Vegetation Response to ClimateVegetation Response to Climate Faunal Response to ClimateFaunal Response to Climate

COCO22 Sequestration Sequestration

Land SurfaceLand Surface

Effects of Land Surface on the Climate Effects of Land Surface on the Climate SystemSystem AspectAspect ElevationElevation AlbedoAlbedo

Response to the Climate SystemResponse to the Climate System River systemsRiver systems Sea level changeSea level change Glacial evidenceGlacial evidence

CryosphereCryosphere

Ice ExtentIce Extent AlbedoAlbedo

Feedback EffectsFeedback Effects Temperature ControlTemperature Control

Energy Balance in the AtmosphereEnergy Balance in the Atmosphere

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

Energy BalanceEnergy Balance

Time Scales of Climatic VariationTime Scales of Climatic Variation

Climate Varies on All Time ScalesClimate Varies on All Time Scales Driving ProcessesDriving Processes

Climate Variation Over Multiple Climate Variation Over Multiple ScalesScales

Variations of the Earth’s Orbital Variations of the Earth’s Orbital ParametersParameters

James Croll; Scottish natural historian James Croll; Scottish natural historian 18671867

Milankovitch; Elaborated on Croll’s original Milankovitch; Elaborated on Croll’s original hypothesis in 1941hypothesis in 1941

Berger; Advances Milankovitch’s work in Berger; Advances Milankovitch’s work in the late 1970sthe late 1970s

Milankovitch CyclesMilankovitch Cycles

EccentricityEccentricity – 95,800 year period. Changes in – 95,800 year period. Changes in the orbital path of the Earth around the Sun. the orbital path of the Earth around the Sun. Affects the relative intensities of the seasons.Affects the relative intensities of the seasons.

ObliquityObliquity – 41,000 year period. Changes in – 41,000 year period. Changes in axial tilt of the Earth.axial tilt of the Earth.

PrecessionPrecession – 21,700 year period. Wobble of – 21,700 year period. Wobble of the axis causing a precession of the equinoxes. the axis causing a precession of the equinoxes. Perihelion during Northern Hemisphere summer Perihelion during Northern Hemisphere summer occurred 11,000 years ago.occurred 11,000 years ago.

Orbital FactorsOrbital Factors

Wobble on the Earth’s AxisWobble on the Earth’s Axis

PrecessionPrecession

Insolation and Insolation and 1818OO

Long Term Solar RadiationLong Term Solar Radiation

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