Modeling Ecosystems and Climates A Teaching Simulator for Systems - PowerPoint PPT Presentation

Modeling Ecosystems and Climates A Teaching Simulator for Systems Dynamics Work Partially Brian S. Blais supported from NASA Rhode Science and Technology Island Space Grant Consortium Bryant University

Introducing Systems Stock and flow Diagrams d (mice) = + b (mice) − d (mice) dt differential mice ′ = + b (mice) − d (mice) equations = 1 . 1 b = 0 . 08 d

Current Tools Spreadsheet Excel, Numbers, Google Spreadsheet Graphical Stella, Powersim, Vensim, Simile

Current Tools Spreadsheet Graphical

Spreadsheet Pros Cons Students already Does not Scale Familiar Well Students Write the Equations can get Simulation Itself Messy Numerical Instabilities

Current Tools Spreadsheet Graphical

Graphical Programs Pros Cons Nice Interface for Commercial Simple Systems Cumbersome with Learning Curve Large Systems Not extensible

Cumbersome

Python Easy language nasa, google free scientific computing support ode support

The Simulator

Equations And Flows Specify either Full equations... ...or Inflows/ Outflows to Stocks

Predator-Prey r · deer 2 /K r · deer Births Deer Deaths c · deer · wolf D · deer · wolf Births Wolf Deaths W d · wolf

Predator-Prey

Kermack-McKendrick Infectious Disease Model

Coffee Cup Model Newton’s Law of Cooling Energy Balance

Coffee Cup Model

Coffee Oscillations

Coffee Oscillations

Coffee Oscillations Analogy with Earth Surface Temperatures Noon 3PM

Daisyworld Model White daisies Black daisies Available fertile land

Daisyworld Model

Daisyworld Model

Daisyworld Model Solar Input doubles over this time

Higher-Order

Future directions Better user interface 2-D, 3-D, N-D equations Thanks! Work Partially supported from NASA Rhode Island Space Grant Consortium