Why is climate modelling stuck? asked mt, and Bryan weighs in too. So I don’t see why I shouldn’t too. This is no kind of comprehensive list or manifesto, the way mt’s is. Just some random thoughts.
First of all, there are too many GCMs, and some of them are cr*p, so much so that they should simply be thrown away. I suspect that certain countries simply built them because they wanted “their” model to appear in the IPCC reports. There are 20+ coupled GCMs in IPCC, and we don’t need that many. I don’t know how many we need – certainly more than one. In fact, I rather suspect that of the total of model development person-hours, more than 75% goes into the top 5 models (plucking random numbers out of the air here) so this may not be a huge problem.
Like mt, I think its time to throw away the Fortran. Apart from anything else, its bad for your job prospects :-). Ideally, there should be a model description language, which would then compile into whatever language you wanted. If you’re discretising a PDE, its a bit mad to have to write the code for that by hand. Machines can do that for you. My pet idea here would be a SourceForge opensource model, probably in C++.
Probably, we should throw away the idea of scientists writing the code. Scientists should do science. Software engineers should write code, based on the documentation that the scientists provide. The reason we don’t have SE’s writing code is because we can’t afford them, not because its a bad idea (what do you mean “we”, White Man?).
Down at the trivia level, we don’t need to worry about memory. We have memory to excess.