CHEMISTRY

In February 2007, MeteoSwiss began production weather forecasting using a Cray supercomputer located at the Swiss National Supercomputing Centre (CSCS). This is a key transition to a scalable supercomputing technology that will allow MeteoSwiss to continue improving forecast quality through model and resolution improvements. Plans to implement higher-resolution forecasts in January 2008 will make detailed forecasts of Switzerland's intricate Alpine topography possible for the first time. This will make Switzerland one of the first countries in Europe to move from the current standard forecast resolution of seven kilometers to a two kilometers resolution. "As an Alpine nation, we are subject to severe weather with high damage potential. In addition, the mountainous terrain can result in discontinuous weather patterns. We can have a destructive storm in one valley while the sun shines in the neighboring valleys, hence higher resolution forecasts will be particularly beneficial to Switzerland," according to CSCS co-Director Dr. Marie-Christine Sawley. "By using the latest supercomputer technology from Cray, CSCS can meet MeteoSwiss' demanding needs for timely and reliable high-resolution forecasts." MeteoSwiss sends raw weather data to CSCS and then uses the resulting forecast information for basic forecasting as well as special needs ranging from frost warnings for the agricultural sector, to snow forecasts for tourism and road maintenance, severe weather warnings for insurance companies and power plants, and specialized forecasts for the aviation industry. On February 1, 2007, after completing accuracy and reliability tests for MeteoSwiss, CSCS began running its current suite of production weather forecasting applications on the centre's Cray XT3 supercomputer system. Additional benchmark tests validated the Cray XT3 supercomputer's ability to run the next-generation, two-kilometer weather forecasts accurately and reliably. CSCS runs the current COSMO-LM (Consortium for Small-scale Modeling-LokalModell) weather model twice a day, at 60 minutes per run. Starting mid-2007, the centre will run the two-kilometer model eight times daily, at 25 minutes per run. The model will become operational for forecast by the start of 2008. Running the model at two-kilometer resolution and under the new operative conditions requires more than 10 times the computing power required by CSCS today. "CSCS was the first site in Europe to select a Cray XT3 supercomputer and has since extended this system by more than 50%. The Cray XT3 system has successfully passed all reliability tests during the evaluation for the future platform for operational weather forecasting in Switzerland. We are very excited about this move," said Ulla Thiel, vice president of Cray Europe. "It proves that the Cray XT3 supercomputer is not just an excellent research engine, but the ideal production system for operational weather forecasting for today's and the future needs of numerical weather prediction."