Introduction to STELLA modeling Tutorials are at loads/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 Level 2. 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 Level 2. Insert Removal Rate Slider from to Insert Graph for CO2 4. Assign Run Specs 0:1: Run for Different Removal Rates

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

Simple CO2 model (continued) 1. Go to Map Level 2. Create Population Stock 3. Create In/OUT flow 4. Create Birth/death Converters 5. Create Connectors 6. Create feedback loops

Simple CO2 model (continued) 1. Go to Model Level 2. Assign Values Population =4000 Birth Rate=0.017 Birth=BR*Population Death=DR*Population Death Rate =Graphic Function from CO2 CO2: ; DR:

Simple CO2 model (continued) 1. Model Level 2. Assign Values Production Rate= Graphic Function of Population

Simple CO2 model (continued) 1. Go to Interface Level 2. Run the model for different values of removal Rate 3. 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 CO2 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.