VIRTUAL CLIMATE CHANGE: AN ONLINE LAB TO SIMULATE MODERN, LAST GLACIAL AND DOUBLED-CO2 CLIMATE OF MONO LAKE, CA USING AN ENERGY BUDGET APPROACH

Climate change is commonly discussed in introductory science classes in high schools and colleges. The focus of discussion is often the impact of doubled CO₂ on the climate system. One approach to understanding this impact is through an energy budget model, such as described by Pease (1987). However, many students blindly assume model output is accurate and reliable. With this in mind, we are developing a web-based lab that allows students to run and validate an energy budget model. The model is applied to the Mono Lake, CA area where there is clear geologic evidence of climate change during the Late Quaternary. Several tools are available to the student. The first tool is used to select a month and time period (modern or last glacial maximum: 21.5 ka). The second tool is used to correct solar illumination (at solar noon) for the declination of the sun and the latitude of Mono Lake. The third tool provides a vegetation map and lake extent for the chosen time period. Students use this map to compute vegetation albedo and surface illumination. The fourth tool is used to adjust the concentration of atmospheric CO₂ as a function of time. The fifth tool adjusts for cloudiness and winds (meridonal transport of heat). Given this input, an energy budget is computed. A tool is then provided that converts energy into temperature and adjusts temperature based on elevation and lapse rate. Modern temperatures and estimates of climate change during the last glacial are provided so that students can validate model output for their chosen scenario. These data help guide discussions on confidence in the energy budget approach to modeling modern climate or climate during the last glacial maximum. The model can then be used to simulate temperature in a doubled-CO₂ climate. Students now have several pieces of information with which to evaluate their temperature estimate for a doubled-CO₂ climate.

Pease, R.W., 1987, The average surface temperature of the Earth: An energy budget approach, Annals of the Association of American Geographers, 77(3), pp. 450-461.