• Views the interaction between components or systems
• Feedback relationships
• Controls or "Cause and effect"
• Negative feedback
• Towards stability (homeostasis)
• Dimethylsulfide & Phytoplankton
• Positive feedback
• Towards destabilization
• "Closed systems" vs. "Open systems"
• Boundaries & boundary conditions

Models

• Conceptual framework
• Simplified representation of the real world
• Broken down into essential components and interactions
• Static models
• At one point in time
• Dynamic models
• Changing conditions through time
• Simulations
• Numerical calculation of detailed response to new conditions

• Goals: to simulate:
• Chemical cycling
• Oceanic circulation
• Atmospheric circulation
• Temperature distribution
• Precipitation
• Ecological distribution
• Primary productivity and fisheries
• Location of resource accumulations
• Geochemical box models
• Reservoirs
• Reservoir size or stocks or sinks
• Fluxes or flows
• Equilibrium
• Input = output
• Residence time (= size of reservoir / input rate)
• General Circulation Models (GCMs)
• Three dimensional supercomputer models
• Atmosphere
• Oceans
• Finite element analysis
• Coarse resolution
• Generally ~5° X 5°
• Combination models
• Goal: better hindcasting and forcasting ability
• "Global average" vs. "Spatially resolved" models
• Sloan et al, 1997
• Weathering and chemical flux to oceans

• Inadequate understanding of processes
• Inadequate coverage of data in geologic past
• Poor spacial resolution
• Computational power limits chronologic resolution
• The Biosphere is a key part of the Earth System
• Yet, most models are primarily physical/chemical
• Coming up next... the Gaia Hypothesis
 

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For any questions or problems with these pages contact
John Francis
Email: jfrancis@csulb.edu
Phone: 562-985-4928
written by R. Behl.
Last changes: 10 Oct. 1997