Learning from Ike

The National Severe Storms Lab-OU X-band dual-polarimetric radar (NO-XP) was driven to Texas to monitor Ike's wind power and rain volume, said Mike Biggerstaff, associate professor of meteorology and director of the Smart Radar Program who led the team from OU. The NO-XP radar had not yet been used to monitor a hurricane.

Because the new radar is dual-polarization, it can "in essence, sample the shapes of raindrops," Biggerstaff said. This lets researchers determine the volume of rain that will fall in a storm.

That knowledge is key in hurricane prediction, because inland flooding is the cause of the most loss of life in U.S. hurricanes, Biggerstaff said. The new radar will improve forecasters' ability to predict floods.

The NO-XP radar also looked at the structure of wind turbulence in Hurricane Ike. Researchers can use that information to better understand strong wind bursts within a hurricane, Biggerstaff said.

The trip to Texas this past week was a collaboration between NSSL and OU, with OU faculty, staff and students on the ground in Texas communicating with NSSL scientists in the lab, he said. Ryan May, meteorology doctoral student, was one of eight who took the NO-XP radar to Texas Sept. 9, returning Sunday night.

It was May's first major field experience, and he said he'd definitely do it again. "It was exciting to be out in the field testing some new equipment," he said. The reason for the trip was sobering, though.

"Of course, you know that other people are not excited about this, (are) in danger of losing their homes and stuff," May said. "So there's a mixed feeling about it."

There were also dangers for the team, which monitored the storm from inside a converted ambulance.

"It's a little surreal and kind of a little scary feeling when you're sitting in a car and actually rocking back and forth," May said.

But the team picked a safe location to await the storm. They parked the radar and monitoring vehicles at the Brazoria County Airport southwest of Houston. Winds got up to 85 miles per hour at about 2:30 a.m. Saturday, but the area was open so there wasn't any dangerous debris flying around, Biggerstaff said.

The team was on the west side of the hurricane's eye, where the wind speeds were weaker because of frictional interaction with land as the circulation goes back off-shore, Biggerstaff said. To the east of the eye, where the winds were coming on-shore, the wind gusts were reported to be around 105 miles per hour, he said.

One of the things the team was testing with the new radar was whether raindrops are shaped differently in hurricanes than other storms because of the high winds, he said. The information is necessary in order to use dual-polarization radar to predict flooding from hurricanes.

Preliminary results from the research this past week show that the shape of raindrops was affected by the hurricane's high winds, Biggerstaff said.

Graduate meteorology student Terra Thompson said she also learned a lot from the trip. She hadn't had a lot of experience with hurricanes, as most of her field work was with tornadoes on the plains. She said the main difference this time was the amount of preparation work involved.

"Tornadoes and storms are more of a last-minute thing," she said. But preparing for the hurricane was interesting to Thompson. She talked to the locals and watched them evacuate in the lead-up to the storm's landfall.

The night before Ike hit, the OU team stayed in a hotel that had closed to the public. The only other occupants were members of the National Guard. "I thought that was kind of crazy," Thompson said.

Julianna Parker 366-3541 jparker@normantranscript.com
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