The Met Office has invested £24m in two new supercomputers to improve the reliability of its weather forecasts through a six-fold increase in computing power.

The NEC SX-6 systems went live last week, with 892GB of memory, 30TB of hard disk and 60 processors, delivering eight gigaflops of power - eight billion calculations per second.

The new computers are supporting the Met Office's switch to a method of forecasting called 4DVAR, which not only uses all available weather data at a single point in time, but also uses data from a range of times to build a more accurate model.

'This isn't a new idea, but we couldn't use it before. It's a better way of using observational data, not only in three dimensions, but also including a time aspect,' said a Met Office spokesman.

The new system receives detailed global meteorological data from satellites four times per day, which are analysed and fed into a system.

'If we're doing a midday forecast now, we can use data from a range of other times during the day and get the best fit of what the weather will be. We've had this data available before but it couldn't be fully used because the computational power wasn't available,' said the spokesman.

'These systems should reduce the number of "busts" in forecasting, where we get things badly wrong.'

The Met Office expects to improve on its current rate of 86 per cent forecast accuracy.

'We were expecting good results, but the magnitude of the improvements has been a pleasant surprise,' said Met Office chief scientist John Mitchell.

Further capacity is already planned, with the performance of the new systems due to be doubled by next summer.

UK takes the lead in supercomputing

The UK has overtaken Germany as the European country with the largest number of the world's most powerful supercomputers, according to the latest TOP500 supercomputing list. The UK has 36 systems on the list, to Germany's 34.

The fastest machine, a football pitch-sized NEC Earth Simulator in Yokohama, Japan, retains number one position.