Atmospheric Simulation

This page contains that actual simulation of atmospheric evolution in a Java applet below. It should be pointed out that there are many inaccuracies in this model and possibly many bugs in the code as I have not had a large amount of time to debug it. Also, the only browsers that I have found that runs this applet properly are HotJava by Sun and IE 4.0 (after switching some of the code back to Java 1.0 syntax it also runs in Netscape 4.0). Every browser I have tried can properly display the top tool bar with the start/stop button and the viewing pull down menu. However, below those should appear a number of graphs. If these are not present on your browser and you want to see this applet I would suggest downloading HotJava or IE 4.x. (Dr. Toon, Tony and I loaded HotJava onto Dirk and it is in the Program Files directory. If you can’t find it when you log on Tony have offered to help out.)

You can scroll down now to see that applet itself and determine if it is working before reading these directions for its use. The applet has two views, a setup view and a run-time view. The program begins in the setup view where you can see graphs of the impact fluxes and the solar flux as a function of time. These graphs are adjustable. You can alter the value of one of the data points by moving the cursor near it then clicking and dragging the point to the value you want. The initial settings are exponential curves.

After you have configured the time series you should select "Run" under the viewing menu. This will switch the display to show a number of other graphs including abundances to the various components and the temperature profile of the atmosphere. At the beginning the temperature profile is set to zero. To begin the simulation, simply click the start button. The system will then evolve for a billion years (if you are willing to wait that long). The radiative transfer model is performed by a rather large system of linear equations, which are solved at every time step and are the major consumers of CPU time in the simulation. Unfortunately, the behavior of these equations at the current time is not 100% satisfactory, but as mentioned above there hasn’t been sufficient time to debug and correct the model. While the simulation is running a yellow bar will be displayed on the graphs that are a function of time to indicate how far through the one billion years the simulation has progressed.