Introduction to STELLA

modeling

Tutorials are at

http://www.iseesystems.com/community/downloads/tutorials/ModelBuilding.aspx

Why STELLA??

STELLA offers a practical way to dynamically visualize and communicate

how complex systems and ideas really work.

Easy-to-use, STELLA models provide endless opportunities to explore by

asking "what if," and watching what happens

STELLA models allow you to communicate how a system works – what goes

in, how the system is impacted, what are the outcomes

Model equations are automatically generated and made accessible beneath

the model layer

Simple CO2 model

•Open Stella Program•Go to Map Level•Open New File•Create CO2 Stock•Create Production and Removal Converters •(Production and Removal Rates)•Create Connectors

Simple CO2 model (continued)

1. Go to Model Level2. Assign Values:• CO2=100• Production Rate=0.02• Removal Rate=0.01• Removal=CO2*Removal

Rate• Production=CO2*Product

ion Rate

Simple CO2 model (continued)

1. Go to Interface Level2. Insert Removal Rate Slider from 0.005 to 0.033. Insert Graph for CO24. Assign Run Specs 0:1:1005. Run for Different Removal Rates

Simple CO2 model (sensitivity)Go to Sensitivity Specs and Specify 5 runs for PR=0.02:0.01:0.06Define Graph Type= Comparative

Graph

Simple CO2 model (continued)

1. Go to Map Level 2. Create Population Stock3. Create In/OUT flow4. Create Birth/death Converters5. Create Connectors6. Create feedback loops

Simple CO2 model (continued)

1. Go to Model Level 2. Assign ValuesPopulation =4000Birth Rate=0.017Birth=BR*PopulationDeath=DR*PopulationDeath Rate =Graphic Function from CO2 CO2: 10-10000; DR:0.013-0.05

Simple CO2 model (continued)

1. Model Level 2. Assign ValuesProduction Rate= Graphic Function of Population

Simple CO2 model (continued)1. Go to Interface Level2. Run the model for different values of removal Rate3. Interpret Results

Possible Research Project:

Earth’s Carbon Cycle and Global Warming

Possible Research Project:

Earth’s Carbon Cycle and Global Warming

Using Stella Earth Carbon Cycle Model investigate the sensitivity of average surface temperature to changes in different aspects of Carbon Cycles (amount of earth entering atmosphere from burning fossil fuels, deforestation, oceanic processes, etc.)

Include additional Feedback loops (e.g. atmosphere-to-ocean flux increases with the increase of surface temperature) into the Stella Model and document their effects.