Nasa launches drones to study storms
11 September 2013, 18:33
Atlantic - Nasa scientists are using former military
surveillance drones to help them understand more about how tropical storms
intensify, which they say could ultimately save lives by improving forecast
models that predict a hurricane's strength.
The unmanned Global Hawk aircraft were designed to perform
high-altitude, long-endurance reconnaissance and intelligence missions for the
Two of the original
Global Hawks built in the developmental process for the military have found new
life as part of Nasa's research mission, studying storms that form over the
Atlantic Ocean. Nasa planned to launch one of the drones from its Wallops
Flight Facility on Wednesday to study Tropical Storm Gabrielle, which re-formed
in the Atlantic on Tuesday.
"The biggest scientific question we're trying to attack
is why do some hurricanes intensify very rapidly and why do others not
intensify at all? In the last 20 years, we've made terrific progress in
forecasting where hurricane tracks will go," said Paul Newman, deputy
project scientist for the research mission. "But we've made almost no
progress in the past 20 years in forecasting intensity."
More accurately predicting a storm's intensity would help
government officials and coastal residents decide whether an evacuation is
needed, as well as avoid developing a false sense of security among residents
who frequently cite failed storm expectations as a reason not to leave their
homes when warned to do so.
There are two questions on which Nasa scientists primarily
want the drone research to focus. One is what role thunderstorms within a
hurricane play in its intensification. Researchers aren't sure if the
thunderstorms are a driver of storm intensity or a symptom of it.
The other is what role the Saharan Air Layer plays in the
tropical storm development. The Saharan Air Layer is a dry, hot, dusty layer of
air from Africa. Scientists have been at odds with each other over whether it
helps hurricanes strengthen or does the opposite. One school of thought is that
the Saharan Air Layer provides energy for storms to grow, while others have
suggested it is a negative influence on storm growth because of the effect the
dry air has on wet storms.
"There's a bit of a debate in terms of how important it
is, one way or the other," said Scott Braun, a research meteorologist at Nasa's
Goddard Space Flight Centre in Greenbelt, Maryland, who is the drone project's
This is the second year Nasa has launched Global Hawks from
the Eastern Shore of Virginia, a strategic location that allows drones to spend
plenty of time studying storms shortly after they form off the coast of Africa
or as they approach the Caribbean Sea or Gulf of Mexico.
This year's mission will end later this month, and the third
and final year of the project's flights will start again next August. Nasa officials
hope three years of flights will give them enough data to begin answering their
The drones are considered advantageous over manned aircraft
because they can fly for much longer periods of time than traditional research
aircraft and at much greater altitudes. Global Hawks can spend up to 28 hours
in the air at a time and reach altitudes up to 19.8km, or roughly twice that of
a typical commercial airliner.
By comparison, specially equipped P-3 Hurricane Hunter
aircraft that fly directly into a storm typically do so at low altitudes of 300m
to 3 000m. Researchers say having a broad overview of a storm can help
them understand things such as whether air moving away from a storm helps it
"As a Hurricane Hunter goes through a storm, they get
very detailed information," Newman said. "Imagine that this [Global
Hawk] will do kind of a cat scan of a hurricane, but Hurricane Hunters go in
and it's like you're using a fine scalpel to look at the details of the
patient, if you will."