August 14, 2001. Copyright 2001. Graphic News. All rights reserved.

Satellites and robot planes to probe hurricanes

LONDON, August 14, Graphic News: Scientists will use a fleet of satellites, aircraft and sea-skimming unpiloted Òaerosondes,Ó to probe the fury of Atlantic hurricanes over the next six weeks.

With the hurricane season hitting its peak period, National Oceanic and Atmospheric Administration (NOAA) hurricane forecasters said they expect a total of nine to 12 tropical storms, of which six to eight may become hurricanes, with two to four of those becoming major hurricanes by seasonÕs end on November 30. 

On average, normal to slightly above normal seasons feature two to three land-falling hurricanes in the United States, and one or two in the Caribbean.

Beginning on August 16, pilots, researchers and supporting technicians based at the Jacksonville Naval Air Station in Florida will wait for storms to form off the coast. When a hurricane approaches to within about 1,200 miles (2,200 km), the NASA-led team will launch its aircraft for observations, coordinated with NASA spacecraft orbiting overhead.

The $3.5-million campaign -- dubbed the Convection and Moisture Experiment (CAMEX 4) -- includes five NASA field centres, NOAA, the National Center for Atmospheric Research and 10 U.S. universities. In all, some 100 people will be involved.

ÒWe will have six or seven aircraft inside the hurricane which are measuring microphysical properties,Ó said Ramesh K. Kakar, manager of NASAÕs Atmospheric Dynamics Program and the CAMEX 4 leader. ÒSo we have remote sensors on the high-flying aircraft and we have in situ sensors inside the hurricane. NASAÕs going to learn a lot about the moisture content of the hurricane and the precipitation pattern inside of the hurricane.Ó

Scientists expect the data collected will increase their understanding in three broad areas: how fast water cycles through the atmosphere, the relationship between regional weather and global climate change, and how new data collection and assimilation technology can improve weather forecasting.

NASAÕs Terra and QuikSCAT satellites -- soaring 500 miles (800 km) above the earth -- will monitor hurricanes spinning across the Atlantic from the coast of Africa.

Beneath their orbits, NASAÕs ER-2 -- a converted U-2 spy plane packed with ÒEarth ResourcesÓ sensors and cameras -- will fly over the storms at altitudes as high as 70,000 feet (21,300 metres).

Down below, flying at 27,000-45,000 feet (8,230-13,720 metres) NASAÕs DC-8 flying laboratory and NOAAÕs new Gulfstream IV SP storm-chaser will fly through the hurricane collecting data.

And lower still will be NOAAÕs two Lockheed WP-3D Òhurricane-hunterÓ turboprops; weather reconnaissance versions of the U.S. Navy surveillance plane forced to land in China in April. The hurricane-hunter, with up to 17 mission specialists as well as a flight crew of four, carries a nose boom to measure gust velocity, a variety of airflow indicators and a sophisticated weather radar.

These aircraft will be joined by two WC-130 hurricane hunters of the Air Force ReserveÕs 53rd Weather Reconnaissance Squadron flying out of Puerto Rico. During their 10-12-hour flights these will collect data as well as samples throughout the lower part of the hurricane.

CAMEX 4 will also see the introduction of Australian-built unmanned aerial vehicles called ÒaerosondesÓ that fly at altitudes unsafe for piloted aircraft. Flying very close to the surface of the sea-- between 500-1,500 ft (150-460 metres) -- the ÒUnmanned Aerial VehiclesÓ (UAVs) will skirt the edges of the hurricanes at first, recording pressure levels, temperature, relative humidity and wind velocity.

The robotic aerosonde uses Global Positioning System and on-board storm tracking for autonomous navigation, relaying data in real time.

Powered by a 24-cc model aircraft engine the UAV has a 9.5-feet (2.9-metre) wingspan, carries about four pounds (1.8 kg) of payload and can fly for up to 30 hours with a maximum range of 1,600 miles (2,965 km).

ÒAs we gain more confidence we might try to send it through the eye, but weÕve got to see how it performs,Ó said Robbie Hood of NASAÕs Marshall Space Flight Center, the lead mission scientist for CAMEX 4.

ÒTheyÕll be collecting measurements and sending them back to us in real time, just to tell us more about the interactions between the ocean and the storm," Hood said.

Of particular interest will be how hurricanes intensify and weaken, and what factors influence the direction of their tracks. Predicting just where a hurricane will make landfall and just how bad it will be when it gets there is extremely important for emergency planners.

By the time the experiments end on September 24, NASA expects to have generated enough data to keep scientists busy for about two years. NASA has budgeted a further $5 million for data analysis.
/ENDS
Sources: NASA, NOAA, Aerosonde