From the time of the first computers the Met Office has used state-of-the-art supercomputers for numerical weather prediction and, more recently, also for predictions of global climate. Developments in computer hardware technology, combined with advances in numerical methods, and an increased understanding of atmospheric and oceanic processes over this period, have lead to steady improvements in the accuracy and timeliness of forecasts.

The Met Office computer systems used over the years reflect evolving trends in supercomputer technology from the scalar IBM 360/195, through the vector Cyber 205, the multi vector-processor Cray C90, massively parallel Cray T3E, the NEC SX-8 and SX-6 to the IBM system. The Met Office has consistently used state-of-the-art computer architectures for achieving near-optimal performance from its numerical models.

In early 2005 the Met Office accepted the first production NEC SX-8 supercomputer in the world. This system provided additional capacity to the NEC SX-6 computer systems used by the Met Office in Exeter. The SX-6 and SX-8 machines were divided into 'nodes' with each node containing eight processors. The combined systems deliver more than 13 times the sustained power of the previous Cray T3E computers, which the SX-6 replaced in 2004.

For operational resilience, the systems were divided between two halls, with the SX-8 and the 15-node SX-6 cluster in one hall, and the 19 node SX-6 cluster in the other. This enabled the operational forecast to be maintained even if one of the halls was unavailable for any reason.

In 2008 we signed the contract for our new supercomputer from IBM. The IBM system is capable of 125 trillion calculations per second and will be the second most powerful computer in the UK, and in the top 20 worldwide. The five-year contract includes a mid-life upgrade so, by 2011, the computer will be 30 times more powerful than the NEC machines.