Supercomputer Uses Lightning

'Deep Thunder' forecasts Irene's urban impact

Hurricane Irene's looming threat on the weather forecast may compel you to stock up on bottled water and put up the shutters, but cities and businesses must also worry about dealing with flooded streets, emergency evacuations and power outages. Luckily, some have begun turning to an IBM supercomputer model that can help them decide on a practical response regarding anything from rainstorms to blizzards.

The "Deep Thunder" simulation not only delivers precise weather forecasts up to three days ahead of time for client cities or businesses , but also predicts possible storm damage on city or business infrastructure such as the power grid. Such information can help cities decide how many snow plows to put on the streets, or aid utility companies in sending out repair crews to fix downed power lines.

"We have to think about the business impact question," said Lloyd Treinish, chief scientist for IBM's Deep Thunder. "If all we can do is the weather, we haven't solved the problem yet even if there's value in the improved weather prediction."

Deep Thunder has already begun simulating the possible impact of Hurricane Irene for clients in New York City, as well as IBM's own labs located around New York State. It can provide anywhere from 24- to 84-hour forecasts depending on what the client needs and how much data is available.

"In general, the first 24 hours will be more accurate (e.g., for thunderstorms)," Treinish said. "But we have seen circumstances where we don't see a lot of difference in accuracy even three days ahead."

IBM previously did weather predictions for Florida during Hurricane Wilma in 2005. The National Weather Service forecasts had showed heavy rainfall and strong winds in Miami, but Deep Thunder more accurately predicted where rainfall would take place and showed how most of the hurricane threat would come from gusty winds.

Building better predictions That's not to say IBM is trying to steal the thunder of the National Weather Service — the latter uses much of IBM's hardware and software technology. But whereas the National Weather Service must provide broad weather forecasts for the entire United States, IBM works with commercial clients to create more precise forecasts tailored to their needs.

Oak Ridge Leadership Computing Facility | Supercomputers and ...

Two Hurricane Rita simulations use different numerical methods. The Reisner group’s HIGRAD code can simulate both liquid and solid elements in either a Lagrangian framework (right panel) using a particle-in-cell approach or the more typical Eulerian cloud modeling approach (left panel). Differences between the two approaches are the result of numerical errors produced by the Eulerian cloud model due to its inability to accurately resolve the movement of sharp cloud boundaries such as those occurring near the hurricane eye wall. Image courtesy of Jon Reisner, Los Alamos National Laboratory

In 2005 a tropical depression formed over the Bahamas on August 23 and intensified to a storm—Katrina—on August 24. Growing to a Category 1 hurricane, Katrina crossed southern Florida on August 25 and weakened over land. Strengthening rapidly over the Gulf of Mexico, however, she grew from Category 3 to 5, with winds in excess of 175 miles per hour, in just 9 hours. Katrina made her second landfall, in Louisiana on August 29, as a Category 3 hurricane with 111 to 130 mile per hour winds. Ultimately, the storm and subsequent floods took a confirmed 1,836 human lives in seven states and displaced more than a million people.

The complex processes of hurricane development are not readily understood or easily studied. That makes predicting the progression of a storm difficult. Now, information from major hurricanes of the last two decades such as Katrina is being put to good use by scientists striving to understand how hurricanes intensify. A research team led by Jon Reisner of Los Alamos National Laboratory (LANL) is employing the Oak Ridge Leadership Computing Facility’s (OLCF’s) Jaguar supercomputer to use data from lightning detectors and even wind instruments mounted on planes flown into the eye of a hurricane to improve atmospheric models. These simulations may lead to more accurate prediction of hurricane intensities and better preparation of the public for these inevitable disasters.

Lightning

Lightning, Physics and Effects

Lightning

Lightning

Lightning