Teach the Earth > Complex Systems > AGU Modeling Workshop 2010 > Modeling Exercise Ideas > Water Vapor Feedback on Earth's Warming Atmosphere

This is a partially developed activity description. It is included in the collection because it contains ideas useful for teaching even though it is incomplete.

# Water Vapor Feedback on Earth's Warming Atmosphere

Meredith Hastings, Department of Geological Sciences, Brown University

Topic: Climate, climate forcings, solar forcings
Course type: Upper level undergraduate course

## Description

Design a model to calculate changes in insolation on Earth due to changes in orbital parameters such as obliquity, eccentricity, and precession. Calculate how much the temperature on Earth varies given different orbital parameters - case A would be applicable to present day, case B applicable to last glacial maximum, case C applicable to another interesting paleoclimate minimum or maximum, case D would leave it up to the students who provide explanation for the choices they make. Take case A or B and test the sensitivity of the temperature on Earth to the other variables in your equation. Do your predicted temperature variations match those based on observations (paleoclimate proxies)? Discuss the implications of the difference between your temperature change predictions and those that are observed. What other physical mechanisms would you invoke to modify the temperature to better agree with observations?

## Learning Goals or Outcomes

• develop a deeper understanding of the radiation balance equations for Earth
• develop an intuition for how the Sun governs temperature on Earth and the sensitivity of surface temperatures to different variables
• develop a quantitative understanding of how much orbital parameters (and their variation) determine temperature on Earth
• determine what forcing mechanisms are important for modifying Earth's temperature over time

## How would you assess whether those goals have been met?

1. Creation of the necessary equations
2. Are quantitative outcomes in the assignment correct?
3. In case D where the students can choose to create their own scenarios and in testing the sensitivity of their model, I would be looking to see if they understood how to manipulate the different variables in the model and how they explain their choices.
4. In the discussion, do the students develop a sense of how sensitive (or insensitive) the Earth is to changes in the sun? Can they correctly identify other forcing mechanisms?

## References

Wallace and Hobbs, Atmospheric Science, Academic Press