Complex simulations such as the weather require lots of calculations that are all dependent on each other - exactly the kind of job that calls for a supercomputer.
Weather forecasts use models of ocean and atmospheric flow, plus a detailed understanding of how weather systems interact with geographical features (such as oceans, seas and mountain ranges), to predict how likely particular weather events are to occur in the near future. They can also be used to model what might happen if the Earth’s climate were to change, such as global heating caused by greenhouse gases.
DKRZ – the German climate research centre – has two super- computers: ‘Tornado’, used for model development and test runs, and ‘Blizzard’, an IBM Power6-based supercomputer. The Blizzard, which is “designed for optimal performance and efficiency for complex simulations with climate models”, is typical of a large proportion supercomputers in that it contain processors with quite different architectures to those found in most desktop systems (IBM Power6 processors instead of Intel or AMD chips) – you can read more about this here [CPUs, GPUs, MICs]. Blizzard has 8448 processor cores and can reach 158,000 Megaflops. A thousand megaflops is a teraflop – you can see more about this here – so that number could also be described as 158 Teraflops.
Here, you can find out how scientists work out the weather. You can find out about how weather data is incorporating new types of interactions, allowing modelling at finer scales. The next generation of supercomputers allows simulations of multiple scenarios with different outcomes, where complex feedback mechanisms play an important part.