Simple climate simulator

Question

I'd like to find a program, library or code that can perform a simple climate simulation. Programs that include this functionality - for example a video game - are also fine.

My motivation is that I'd like to build a piece of software that can take terrain + sea data as input, and via simulation, output parameters such as temperature and precipitation, so that biomes can be assigned. This software can then be used as a tool for creating realistic settings for fiction or games. Building such a piece of software can also be very fun!

My complaint about the methods used to determine climate, that I know of, is that they are too simple, too unrealistic, and ignore phenomena that can have a huge effect on climate, such as ocean currents or rain shadows.

Criteria

I'd like something that is accessible to hobbyists, as opposed to climate researchers. Something that can be run in less than one day on a typical personal computer.

Examples of current systems and their limitations:

• Amit Patel's article on map generation includes assignment of biomes, but it only uses distance from water as an input for precipitation. This is fine for what it was designed for - small islands - but is too limited for global terrain.
• The world generation in Dwarf Fortress seems very comprehensive. I'm not too familiar with it though. I see it can model rain shadows though, which is nice.

I'm not too picky about exact features, only something that's between "latitude + elevation" and "supercomputer modelling". Some features that might fit this category include:

• Ocean currents
• Orthographic lift / rain shadows
• Prevailing winds
• Air masses, weather fronts

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Note: I've asked similar questions on GD.SE and Physics, unfortunately both have been closed as too broad. I hope softwarerecs is a better fit.

Answer 1

http://edgcm.columbia.edu/support2/faq/

EdGCM provides a research-grade Global Climate Model (GCM) with a user-friendly interface that can be run on a desktop computer. For the first time, students can explore the subject of climate change in the same way that actual research scientists do. In the process of using EdGCM, students will become knowledgeable about a topic that will surely affect their lives, and we will better prepare the next generation of scientists who will grapple with a myriad of complex climate issues.

http://www.easterbrook.ca/steve/2009/06/getting-the-source-code-for-climate-models/

Links to many different models and code. Somewhat out of date.

Note that some of your criteria may be impossible.

• Ocean currents are one of the real bugbears right now. Currents work on a time scale of decades where the atmosphere works on a time scale of weeks, and yet they are tightly coupled.

• It's not clear that there is such a thing as 'equilibrium' More and more of both historic climate and model behaviour shows sudden lurches between multiple temporarily stable states.

A big help in clarifying what you want may be this article:

http://www.aip.org/history/climate/simple.htm and followed by the one on general circulation.

Warning: I've been spending an hour a day on this site for two weeks now.