From killer hurricanes to global climate change, weather is the biggest uncontrollable factor affecting our daily lives and, at times, our very survival. But early predictions of weather events are becoming faster and more accurate, giving people more time to prepare. At the US National Center for Atmospheric Research (NCAR) a team of scientists has developed sophisticated forecasting models for immediate, long-term and short-term weather conditions.
The Weather Research and Forecasting Model (WRF) is the most widely-used model in the world, with users including the National Weather Service, the Air Force Weather Agency, foreign weather services and commercial weather forecasting companies. NCAR's climate and weather models are moving from Terascale (1 trillion FLOPS) to Petascale class applications, outgrowing conventional computing clusters and reaching a tipping point where adding more CPUs is no longer effective for improving speed. The problem has been particularly acute with applications that involve a real-time component or other time-to-solution constraints.
In examining ways to improve overall forecasting speed and accuracy, NCAR technical staff in collaboration with the researchers at the University of Colorado at Boulder turned to Nvidia GPU computing solutions. After porting to Nvidia CUDA, there was a 10X improvement in speed for microphysics, a crucial but computationally intensive component of WRF. Although microphysics made up less than 1 per cent of the model source code, converting it to CUDA resulted in a 20 per cent speed improvement for the overall model.
'This result is extremely encouraging and timely, coming at a time when we are running out of gas for time-critical forecasts on conventional clusters,' says NCAR’s John Michalakes, lead software developer for WRF. 'We aim to cut the time for a forecast by at least a factor of two as we incorporate this GPU computing technology into more of WRF. I expect the affect of accelerators in weather and climate modelling will be transformative.'
Now NCAR, and the many agencies worldwide who rely on the WRF, are able to produce critically needed forecasts about real-time weather events and developing conditions faster. As a result, people will be able to prepare for these events and get out of harm’s way.
