Part 1—Download Software and Data

Step 1 – Download the Tool and Data

Go to the EdGCM website, download the climate modeling software and install it on your computer. You will need to enter a valid email address. The system will then send an email reply with download links for the Mac and Windows versions of the software. The demo version of the software runs in fully operational mode for 30 days. Link to download EdGCM . Additional instructions for installation are included in the read me text file included in the download package.

Step 2 – Install EdGCM Software - Mac

Download the latest disk image (e.g., EdGCM.dmg) from the Link to download EdGCM . When the license agreement appears, click "Agree" to continue mounting the disk image on your desktop.
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Once the disk image is mounted, simply drag the EdGCM folder to the desktop, or to any other desired location where you (or other users) will have write access. Launch EdGCM by double-clicking on the shortcut inside the EdGCM folder.
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Step 2 – Install EdGCM software - Windows XP / Vista

Download the latest installer (e.g., EdGCM.exe) from the Link to download EdGCM to your desktop, and double-click on the file name to begin the installation process. When the license agreement appears, click "Agree" to continue the installation process. Please note that you may need an administrator's password to complete the installation; if you do, you will need to ask your IT administrator for assistance.
The default installation location for EdGCM is your desktop. You may choose another location, but you (or other users) must have write access for that directory (e.g., C:/>Program Files won't work).
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Select the components of the EdGCM package that you wish to install. We recommend that you leave all choices checked since QuickTime and Java are required to use EdGCM. The QuickTime installer will only run if you do not already have QuickTime installed. The Java installer will replace any existing copy of Java with the latest version from Sun.
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If you do not already have QuickTime and Java on your PC, installation of these components will begin now. Simply accept the license agreements and opt for a typical setup rather than a custom installation. The installation process for these programs may take several minutes each.
Launch EdGCM from either the Start Menu or from the shortcut on your desktop.

Step 3 – Register Your Copy of EdGCM

When you launch EdGCM for the first time, a dialog box will appear, asking you to register. If you have already purchased your copy of EdGCM, type in the license key exactly as given in your confirmation email, and click on the "Enter" button to complete your registration.

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If you wish to use EdGCM in demo mode, leave the license field blank and click on the "Demo" button. You will then have 30 days to try out the software; the demo is fully functional during that time. While running in demo mode, the registration box will appear each time you launch EdGCM, reminding you of the number of days remaining in your free trial.
If you have been using EdGCM in demo mode and decide to make a purchase, leave the license field blank and click on the "Purchase" button. You will be directed first to the EdGCM web site to provide some basic user information, and then to the EdGCM online store (hosted by Kagi) to complete your credit card or PayPal purchase. Once you have received your license key, follow step 1 above to complete registration.

Optional Step – Learn More about EdGCM Performance

The complete EdGCM manual (Acrobat (PDF) 7.2MB Aug15 09) is available to download in pdf. The manual has detailed instructions for users of the software, including information on how fast the software will run on various computers. Climate models are complex and take large amounts of computing time to complete. Teachers who are unsure of their computer's technical capability should check with their IT department for information.

Step 4 – Run the Simulations

Launch EdGCM by double clicking on the icon (alias pictured to the right) in the EdGCM folder. The application will load. The tool bar window will appear. It is from this toolbar window that the user controls the software. The buttons in this window will change depending on the active window.
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Once EdGCM has started up, run the simulations. To run one of the provided simulations and generate the 2 raw model output (data files) you will need for Part 2 of this exercise, click on a simulation name in the ToolBar's Run List to select it, and then click on the "Play" button at the top of the ToolBar to launch the GCM component of EdGCM and start the simulation. The first simulation to run is the Modern_PredictedSST. The second is called IPCC A1 FI CO2. These simulations can take 12 -24 hours to run.
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These calculations are done, for a model with the resolution (8x10) used in EdGCM, in every grid cell once every 15 minutes of each simulated hour, of each simulated day, of each simulated year of a run... and remember, the grid cells are not isolated from each other, but have to pass information across grid boundaries for the every subsequent set of calculations. Each hour of an entire simulation has to be accounted for in the model. That's an awful lot of calculating and bookkeeping to do, so even with faster desktop computers, it takes a while to finish a 148-year run.
When a simulation is completed, the GCM window will give you a message that the run has finished successfully, and in the EdGCM ToolBar run list, you will see a solid blue circle next to the simulation name. Note that the GCM will generate a large amount of output - roughly 2.6 GB for a simulation running ~140 years - so you should make sure you have adequate disk space before starting your simulations. Once the simulation is complete, you will be able to remove about two-thirds of the raw files to free up space on your hard disk.
The GCM component of EdGCM - the actual climate model created by NASA - is an independent program that will launch in a new window, with its own controls for pausing and continuing the simulation. When you first start a simulation, the GCM will run for about one hour and then stop with the message: "First hour completed successfully! STOP 13: The GCM is no longer running." Click on the "Play" button at the bottom of the GCM window to continue the simulation.
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Why does the GCM stop after one hour? When the GCM was first developed by NASA, it needed to run on a supercomputer, a precious shared resource. The scientists could not afford to let the GCM run without first checking to ensure that the model was set up with all the appropriately matched input files, and that the model computer code itself didn't contain any major errors that would produce bad results. Their solution was to allow the GCM to run for the first simulated hour, and then check the results to see if they were reasonable before allowing the simulation to continue. EdGCM retains this feature, partly for historical reasons, but also as a aid for EdGCM users designing their own simulations and experiments.
To free up system resources, you may quit the EdGCM 4D interface (i.e., the ToolBar) at this point. The GCM window itself can be minimized, but do NOT close the window (on Macs) or quit the application (on Windows), or you will stop the model inadvertently. If you need to stop the model temporarily (for user logoff/computer shutdown), click on the "Pause" button at the bottom of the GCM window; this step will allow the model to collect the information it needs to successfully start up again at a later time. You can then quit the GCM from the File menu, or by clicking on the "Stop" button at the bottom of the GCM window. To restart a simulation, simply repeat step 1 above, and the GCM will continue the simulation from the previous stopping point. It is possible to work on other programs with the simulation running in the background.