As the back half of October approaches, the peak of the Atlantic hurricane season is ostensibly winding down – and the post-mortem has begun, with research institutions assessing how well (or poorly) their various weather apparatuses forecasted the year’s major hurricanes. One such apparatus is the ADCIRC Surge Guidance System: a suite of mathematical models aimed at predicting storm surges from incoming storms based on expected hurricane tracks. In an article from Aaron Dubrow of the Texas Advanced Computing Center (TACC), the team behind ADCIRC recently discussed how the tool works – including how it leveraged supercomputing to tackle this year’s record hurricane season.
ADCIRC is a veteran tool, having predicted storm surges (often the most deadly element of a hurricane) for 25 years. Over the course of that time, the tool has been drastically upgraded, explained Clint Dawson, one of ADCIRC’s lead developers and a professor at the University of Texas at Austin. “We’ve added more and more physics, better numerical algorithms, better software, better use of high performance computing resources,” he said. “And it just continues to improve to the present day.”
The ADCIRC system is set into motion whenever a tropical storm forms in the Atlantic Ocean, using data on the storm’s track and wind conditions to forecast storm surge as the storm progresses closer to land. ADCIRC updates these storm surge projections every time it receives new guidance on a storm’s track – and that, of course, requires substantial supercomputing power. Since 2008, the team has found those resources at TACC, which offers ADCIRC emergency access to its supercomputers in the event of a major storm.
TACC itself has been updated in that time, as well – just last year, the center debuted its new Frontera system: an 8,008-node system with two GPU-equipped subsystems that, overall, delivers 23.5 Linpack petaflops and places 8th on the Top500 list of the world’s most powerful publicly ranked supercomputers. Frontera is the new home for emergency ADCIRC calculations, which have themselves been upgraded and optimized for the new firepower at their disposal. With the new supercomputer in-hand, the ADCIRC team is able to run three forecasts in the same hour it used to take to run just one.
“Having Frontera available is incredible,” said Jason Fleming, lead developer and operator of ADCIRC. “Frontera not only has more processors, but also faster processors, which allows us to do so much more. Urgent computing forecasts get stale very quickly. Forecasts need to be ready in time for a leaders’ morning briefing, and if they come late, they’re not actionable.”
Frontera also enables the use of the latest meshes of Texas, Louisiana and Florida – which gives ADCIRC’s storm surge predictions for those areas several times higher resolution than projections produced by the National Oceanic and Atmospheric Administration (NOAA).
Once ADCIRC produces a projection of storm surge, the result is processed by the Coastal Emergency Risks Assessment (CERA) web mapping tool that visualizes the forecasts. CERA, which integrates data from a variety of sources, is used by key decision-makers throughout the U.S. hurricane region to plan resource allocation for emergency response efforts.
“ADCIRC forecasts help us define the threat geography,” said Gordon Wells, a researcher at the University of Texas at Austin who helps to advise the state of Texas on its storm response efforts. In the case of Hurricane Laura (a category four hurricane that made landfall in Louisiana this year), he said, “ADCIRC gave us confidence that we weren’t going to have problems there because of the wind. There was no need to use resources, recommend unnecessary evacuations or do house-by-house searches.”
Crucially, real-time updates to these important forecasts are also possible using Frontera. “If you’re going to create forecasts in near-real time and get an operational product to make meaningful decisions,” Wells said, “the only way is to use supercomputers.”
To read the reporting from TACC’s Aaron Dubrow, click here.