NASA's Unmanned Aircraft Studying Hurricane Leslie

NASA is using an unmanned Global Hawk aircraft over Hurricane Leslie in the Atlantic Ocean during a day long flight from California to Virginia. With the Hurricane and Severe Storm Sentinel (HS3) mission, NASA for the first time will be flying Global Hawks from the U.S. East Coast.

The Global Hawk spent 10 hours collecting data on Hurrivcane Leslie after it took off from NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif., on Thursday.

It is reported that during the HS3 mission NASA will fly two Global Hawks from wallops. These planes will be operated by pilots in ground control stations and can stay in air for 28 hours and can fly over hurricanes at altitudes greater than 60,000 feet.

The goal of the mission is to underlie the hurricane formation and intensity change. The details provided will help the scientists to get indepth information about the roles of the large-scale environment and internal storm processes that shape these systems.

The first Gloabal Hawk that arrived on Sept 7 carried along with it 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 two will be used to 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 NASA's Goddard Space Flight Center in Greenbelt, Md.

This Global Hawk will carry a laser system called the Cloud Physics Lidar (CPL) that will measure the cloud structure an aerosals, the Scanning High-resolution Interferometer Sounder (S-HIS) that remotely senses the temperature and cloud properties, and the Advanced Vertical Atmospheric Profiling System (AVAPS) that 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).