Which Way Does the Wind Blow? Let's Find Out!
On a bluff overlooking the Atlantic, Grady Koch spent a month watching ocean
He beamed a laser over the sea, day after day, measuring conditions offshore
using an instrument called Doppler Aerosol Wind (DAWN) lidar.
What Koch learns from the experiment will be used by scientists to advance
weather forecasting technology -- and also by a consortium hoping to develop
a wind farm in the very spot where the wind data is being taken.
"It's been going well," said Koch, a scientist at NASA's Langley Research
Center in Hampton, Va.
"It works. We're showing that we can measure wind at different heights. One
issue we've been working is, how far can we see? We've been able to see
pretty well out to 12 kilometers (7.5 miles)."
The wind farm is proposed by the Virginia Coastal Energy Research
Consortium, a partnership of universities, state and local governments, and
industry. The Virginia legislature formed the consortium in 2007 to develop
coastal energy technologies.
A wind farm would provide Virginia with about 10 percent of its power
demand, said George Hagerman, a scientist at Virginia Tech, a consortium
"We're at a point now where offshore wind is not just an academic exercise,"
he said. I don't think it's a question of 'if.' It's a question of when."
The consortium, Hagerman said, is working with private and government
agencies to ensure the potential wind farm is placed in an area where it
does not interfere with shipping routes or military exercises, which are
common in the waters off Virginia Beach.
The location under study is about 15 miles off the Atlantic coast in
Virginia Beach, Va. and covers about 240 square miles. Companies wishing to
place wind-powered energy generators in the area would have to sign leases
with the federal government, which controls the waters, Hagerman said.
A huge requirement for persuading industry to invest is providing them with
reliable data about wind speed and direction.
That's where NASA Langley comes in.
The DAWN laser used by Grady Koch is extremely powerful, and capable of
compiling three-dimensional wind profiles. "It's much stronger than anything
you can buy on the commercial market," Koch said.
DAWN is the product of three decades of development for use in weather
Last year, for example, DAWN was part of a research campaign called the
Genesis and Rapid Intensification Process (GRIP) mission. The campaign was
conducted to better understand how tropical storms form and develop into
The laser function of DAWN measures wind speed and direction by tracking
dust and other particles blowing in the wind. The particles, in a sense,
illuminate the wind.
For the current project, DAWN was fitted to a large trailer and towed from
Langley to the experiment site. It's a stone's throw from the ocean at the
Joint Expeditionary Base Little Creek-Fort Story, an Army/Navy installation
at Cape Henry, where the Atlantic meets the Chesapeake Bay.
For NASA, the experiment will add much-needed marine wind data to an
existing 30-year dataset about wind. That information will be used to
improve the capabilities of instruments like DAWN.
The hope is to provide new data for meteorologists so they can make better
forecasts about hurricane intensity, track, and landfall. Eventually,
scientists hope, a DAWN-like instrument will be launched into space to
provide continuous global coverage.
Said Koch of the wind-profiling project: "We're proving a concept."
NASA Langley Research Center