Wednesday, July 1, 2009

Drones seek storms' secrets

This is interesting! I wonder if weather forecasting in general will be helped by this project.
 
Michelle

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Drones seek storms' secrets

New unmanned drones promise better weather insight

BY JIM WAYMER Florida Today
Originally published 09:08 a.m., June 30, 2009
Updated 09:08 a.m., June 30, 2009

The Global Hawk drone will give scientists more information on how storms strengthen, by taking closer and longer looks at storms' eyewalls.

Photo provided

The Global Hawk drone will give scientists more information on how storms strengthen, by taking closer and longer looks at storms' eyewalls.

Predator drones piloted from laptops track al-Qaida in the Middle East and illegal border crossings from Canada and Mexico.

In the middle of the Atlantic, they will hunt hurricanes -- maybe leading to the end of manned reconnaissance flights, or at least the most dangerous ones.

One drone can jet high above a hurricane to scan a storm's origins. Another propels along a cyclone's tail, deep into the eyewall, within a few hundred feet of the ocean surface. Their instruments peer through clouds and sandstorms. They send photos and real-time video.

This new breed of hurricane hunters targets the Holy Grail in hurricane forecasting: better prediction of how storms quickly strengthen. The closer, longer glimpses of a storm's beginnings and eyewall could one day save lives and property.

"We can stay aloft longer," said Ramesh Kakar, a program scientist at NASA in Washington, D.C. "That's a big difference between a drone and a manned aircraft. You're limited by the pilot fatigue."

NASA plans a test flight in September of the Global Hawk predator drone, with hopes of having it ready for next year's hurricane season.

"It's just like having your own little roving satellite," said Robbie Hood, director of the National Oceanic and Atmospheric Administration's Unmanned Aircraft Systems program in Boulder, Colo. "It would be like parking a satellite above the storm."

The Global Hawk cruises at 400 mph and can reach 65,000 feet with up to 2,000 pounds of weather instruments.

Last year, the Air Force transferred two Global Hawks to NASA's Dryden Flight Research Center at Edwards Air Force Base in California. For now, the drones will deploy from there.

But Kakar hopes to make the drone available at NASA's Wallops Flight Facility in Virginia next year.

Aerosonde

To focus resources on the Global Hawk, the federal government this year scrubbed flights of a much smaller hurricane drone that gathers near-ocean data, which forecasters say is vital for improving storm-intensity predictions.

The Aerosonde drone, named after the Australian company that designed it, can fly 500 feet or lower above the ocean.

Scientists say the temperature, pressure and moisture data collected would help to better describe the way energy transfers from ocean to the atmosphere to make a storm's power grow so fast. That could improve warnings for hurricanes such as Charley in 2004, which seemed to fizzle as Charlotte County residents went to bed but grew to a powerful Category 4 storm overnight.

The first Aerosonde drone to venture into a tropical storm launched in 2005 during Tropical Storm Ophelia.

The prop-driven drone weighs roughly 30 pounds and cruises at 50 to 70 mph, at up to 15,000 feet. It can run about 24 hours or more on the 1.6 gallons of fuel it carries.

But the drone has its drawbacks, which caused NOAA and NASA to shelve it this year in favor of focusing on Global Hawk.

"Aerosonde will carry very minor, miniature instruments, and it can't fly very high," Kakar of NASA said. "It has a limited coverage. Also, if you're not careful, it can get destroyed."

NOAA lost one Aerosonde drone, when researchers in 2007 intentionally ditched it into the Atlantic off of North Carolina during Hurricane Noel. They wanted to gather more storm data, rather than return the craft to refuel.

Global Hawk

Federal hurricane researchers decided the larger, much pricier Global Hawk -- a 44-foot-long aircraft with a 116-foot wingspan -- could gather more valuable data, partly because it can carry a much heavier payload of instruments.

The Global Hawk can drop dropsondes -- small devices on chutes that radio sea temperature, salinity and other information back to computers aboard the aircraft -- as the manned flights do, and collect more measurements.

"What I'm trying to do here is simulate a lower satellite," Kakar said.

He hopes to develop air-refueling capability for the Global Hawk, to double its flight time to about 60 hours. Most manned hurricane flights last seven to nine hours.

Others drones in the works include the Altair Predator B, the Global Observer and Zephyr. Each has its pros and cons. The Zephyr, for example, can linger over a hurricane for days at a time, but only with about a nine-pound payload.

NOAA's unmanned aircraft program had a $3.3 million budget last year and $6.3 million this year.

Manned flights

Hood said it could be 30 years before the drones ground the human hurricane hunters.

NOAA's time-tested Gulfstream-IV jet, called "Gonzo," flies into the storms, with a crew of 10, dropping in instruments. And Lockheed's N42RF "Kermit" and N43RF "Miss Piggy" each carry a crew of 18.

The manned flights can improve track forecasts by 20 percent, by deploying dropsondes.

But they give only periodic snapshots, so forecasters can't wait for a longer, closer look into a storm's eye.

"I think over the next decades we're going to see pretty significant improvements in hurricane intensity forecasting," said Scott Spratt, a National Weather Service forecaster in Melbourne.

Contact Waymer at 242-3663 or jwaymer@floridatoday.com.

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