Quaternary%20Environments%20Paleoclimatic%20Reconstruction

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Quaternary EnvironmentsPaleoclimatic
Reconstruction
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Paleoclimatic Reconstruction

• paleoclimatic data provide the basis for
  testing hypotheses about the causes of climatic
  change. Only when the causes of past climatic
  fluctuations are understood will it be possible
  to fully anticipate or forecast climatic
  variations in the future (Bradley and Eddy,
  1991). (Bradley 1999)

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Thresholds

• Nonlinear responses
• Critical thresholds

http//kevin.atkinson.dhs.org/fractals/
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Strange Attractors

• Lorenz attractor
• Meteorologist, 1963

http//www.geocomplexity.com/Global_climate.htm
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Signal to Noise Ratio

• Proxy records catalog the phenomenon in which we
  are interested. This is called signal.
• At the same time they filter that signal and also
  respond to other drivers. This we call noise.
• If you examine the signal to noise ratio you can
  determine the quality of the record.

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Calibration

• Direct information on the phenomenon or other
  proxy materials are used to demonstrate the
  relationship.
• The principle of uniformitarianism.
• Never 100 accurate.

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Analog Situations

• Comparable situations in the past
• No-Analog situations
• Multiple proxies

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Extent

• Spatial coverage
• Palynology Size of catchment
• Dendrochronology Coherent climate signals
• Packrats Range from midden along with coherent
  ecosystems
• Temporal coverage
• Dendrochronology 1,000 years on average
• Palynology often 10,000 years
• Marine Sediments 100,000 years

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Resolution

• Sampling interval
• Dendrochronology Annual
• Lake Sediments 50 - 200 years
• Marine Sediments 500 - 1000 years
• Sedimentation Rate
• Non-Continuous Records
• Glacial Advances

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Frequency Dependence

• Low Frequency Signal
• High Frequency Signal

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Inertia

• Response Time - Lags
• Pollen Assemblages 100 years for the vegetation
  to respond to climate change
• Insect Assemblages Quick generation time, so
  change very quickly with climate
• Autocorrelation
• Dendrochronology - Climate responses

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Climatic Forcing Factors

• Proxies record climate change
• Also record forcing factors
• Volcanic aerosols
• Dust in ice cores
• Carbon Dioxide
• Methane
• Nitrous Oxide

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Feedbacks

• Positive Feedbacks
• Negative Feedbacks

http//www.geocomplexity.com/Global_climate.htm
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Dating

• Utmost importance to determine timing of events
• Synchronicity of timing
• Forcing factors
• Lagged timing

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Levels of Analysis

• Level I
• Field data collection, analysis, and measurements
• Level II
• Calibrated and converted to paleo records
• Level III
• Regionalized paleo records
• Synthesis

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Models

• Simplify a system to its basic components
• Types of Models
• Physical Models
• Globe
• Computer Models
• GCMs
• Conceptual Models
• Flow chart
• Test Hypotheses

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