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The Global Hawk took off from NASA's Dryden Flight Research Center at Edwards Air Force
Base, Calif. , Sep 6 and landed at the agency's Wallops Flight Facility on Wallops Island,
Va., Sep 7 after spending 10 hours collecting data on Hurricane Leslie. The month-long HS3
mission will help researchers and forecasters uncover information about how hurricanes and
tropical storms form and intensify.
NASA will fly two Global Hawks from Wallops during the HS3 mission.
The planes, made by Northrop Grumman, can stay in the air for as long as 28 hours and fly
over hurricanes at altitudes greater than 60,000 feet. They will be operated by pilots in
ground control stations at Wallops and Dryden Flight Research Center at Edwards Air Force
Base, Calif.
NASA has been manned aircraft like C 130s to study the weather, often flying them in rough
weather. But the Global Hawks have helped introduce new capabilities without endangering
human lives.
The NASA mission targets the processes that underlie hurricane formation and intensity
change. The aircraft help scientists decipher the relative roles of the large-scale
environment and internal storm processes that shape these systems. Studying hurricanes is
a challenge for a field campaign like HS3 because of the small sample of storms available
for study and the great variety of scenarios under which they form and evolve. HS3 flights
will continue into early October of this year and be repeated from Wallops during the 2013
and 2014 hurricane seasons.
The first Global Hawk arrived Sept. 7 at Wallops carrying a payload of three instruments
that will sample the environment around hurricanes. A second Global Hawk, scheduled to
arrive in two weeks, will look inside hurricanes and developing storms with a different set
of instruments. The pair will measure winds, temperature, water vapor, precipitation and
aerosols from the surface to the lower stratosphere.
"The primary objective of the environmental Global Hawk is to describe the interaction of
tropical disturbances and cyclones with the hot, dry and dusty air that moves westward off
the Saharan desert and appears to affect the ability of storms to form and intensify," said
Scott Braun, HS3 mission principal investigator and research meteorologist at NASA1s Goddard
Space Flight Center in Greenbelt, Md.
This Global Hawk will carry a laser system called the Cloud
Physics Lidar (CPL), the Scanning High-resolution
Interferometer Sounder (S-HIS), and the Advanced
Vertical Atmospheric Profiling System (AVAPS).
The CPL will measure cloud structure and aerosols such as dust, sea salt and smoke particles.
The S-HIS can remotely sense the temperature and water vapor vertical profile along with the
sea surface temperature and cloud properties. The AVAPS dropsonde system will eject small
sensors tied to parachutes that drift down through the storm, measuring winds, temperature
and humidity.
"Instruments on the 'over-storm' Global Hawk will examine the role of deep thunderstorm
systems in hurricane intensity change, particularly to detect changes in low-level wind
fields in the vicinity of these thunderstorms," said Braun.
These instruments will measure eyewall and rainband winds and precipitation using a
Doppler radar and other microwave sensors called the High-altitude Imaging Wind and Rain
Airborne Profiler (HIWRAP), High-Altitude MMIC Sounding Radiometer (HAMSR) and Hurricane
Imaging Radiometer (HIRAD).
HIWRAP measures cloud structure and winds, providing a three-dimensional view of these
conditions. HAMSR uses microwave wavelengths to measure temperature, water vapor, and
precipitation from the top of the storm to the surface. HIRAD measures surface wind speeds
and rain rates.
The HS3 mission is supported by several NASA centers including Wallops; Goddard; Dryden;
Ames Research Center, Moffett Field, Calif.; Marshall Space Flight Center, Huntsville, Ala.;
and the Jet Propulsion Laboratory, Pasadena, Calif. HS3 also has collaborations with partners
from government agencies and academia.
HS3 is an Earth Venture mission funded by NASA's
Science Mission Directorate in Washington. Earth
Venture missions are managed by NASA's Earth System
Science Pathfinder Program at the agency's Langley
Research Center in Hampton, Va. The HS3 mission
is managed by the Earth Science Project Office
at NASA's Ames Research Center.
Inputs and Pix: NASA
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