Network RAM revisited

Greg Lindahl lindahl at
Thu May 29 14:43:51 EDT 2003

On Thu, May 29, 2003 at 10:55:26PM +1000, Kim Branson wrote:

> Interesting, is weather forecasting limited by computational resources 
> and not data availability?

Yes and no. Groups share datda with each other. But there are 2 things
needed to scale the computation: the first is raw compute power, and
the second is better representation of sub-cell physics. The second is
not a matter of computer power, it's a matter of of a lot of R&D,
which is helped by more compute power (more test runs) but still takes
a lot of time.

Another way that raw compute power can help out is that you can run
ensemble forecasts, which is a bunch of separate runs with slightly
perturbed input data.

By the way, I goofed up my scaling in an earlier post: the amount of
compute power used goes up by the resolution**4 (3 spatial dimensions,
1 time). So going from 40km to 20km uses 16x the computation, roughly.
And no, there is no current machine capable of doing 1km forecasts.

-- greg

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