KNMI (the Royal Netherlands Meteorological Institute) provides weather forecast data on an hourly basis to government agencies, commercial weather bureaux, broadcasters and the media; and the Institute also has a very strong research group specialising in climate research and seismology.

KNMI's critical success factors are to provide high quality, accurate weather forecasts, and to increase the level of available knowledge regarding the Earth's climate - including climate change. Achieving this means maximising the resolution of its models, to enable them to provide increasingly detailed information.

KNMI's history in high-performance computing (HPC) began in the late 1980s. The Institute focused initially on optimising its predictive modelling, and then in 1996 purchased its first Silicon Graphics system, dedicated to weather forecast modelling. This was quickly followed by another Silicon Graphics machine, dedicated to climate research.

"This was a major step forward for us, and was also the moment when things really started to happen in KNMI in relation to modelling," remembers Rene van Lier, Project Manager. "We decided we wanted to increase the resolution of our models so that the information we could get out of them would get better and better. This is why every few years we've tried to make a major leap forward in the performance of our systems."

The most recent of these is an SGI Altix with 240 Intel® Itanium® 2 processors - which, according to van Lier, has given KNMI a solution with 10-15x the compute power of its predecessor - a 68-processor Sun Fire 15K.

To manage its data, KNMI uses two different levels of storage. These are 7TB of online storage, managed by the SGI® InfiniteStorage Shared Filesystem CXFS™, and dedicated to the HPC environment; and a 150TB near-line tape archive, based on a tape silo and the SGI® InfiniteStorage Data Migration Facility (DMF), which is used mainly for research purposes.

"Over the last ten years, the resolution of our weather forecasting models have improved by an order of magnitude," says van Lier. "Ten years ago we had a resolution of 40-55km within the models; with the Sun system we had a resolution of 11km, and with the Altix we want to go to 2km.

"That's quite an effort, and means we're producing a lot more data - around 20x as much each time we run one of our models. All of this is three-dimensional, and we want to increase not only the grid points but also the number of levels at which we do our calculations. We now have more data within the same column of air, making it more accurate, and enabling us to predict the weather longer into the future. Not only has this meant an enormous increase in the amount of data we produce, but also in the number of compute cycles we need to generate the data within a limited timeframe, because the one thing that hasn't changed is that we still need the results within the hour!

"The Altix also enables us to make much longer simulation runs in order to have more detailed information about climate change. The longest run we've had is for a 100 year period, but what we've most wanted to achieve is to have a higher resolution over a longer period of time - so improving our quality both ways."

FURTHER INFORMATION
www.sgi.com/industries/weather