Hurricane Watch: Cue the Earth-Observation Satellites
Tuesday, August 28th, 2012
by AJ Plunkett
Nobody can stop a hurricane or typhoon; a fact that the citizens of New Orleans know all too well. It’s been seven years since the area was pummelled by Hurricane Katrina, leaving countless tragedies in its wake. And Hurricane Isaac is set to hit the New Orleans area on that same day, seven years later.
Practically speaking (and politics aside) the more information that’s known about a gathering storm system, the better a community can prepare for the danger headed its way.
The Havoc of Hurricane Hazel
Certainly, no one was prepared for the devastation that came to Ontario in October 1954 when Hurricane Hazel rolled through, dumping 300 million tons of storm water, and overwhelming waterways and land already saturated by earlier rains.
The flash flooding washed out bridges and streets and swept away whole homes and families. The death toll reached 81, and in Toronto alone, more than 1,800 families were left homeless. In the more than five decades since Hazel, the forecasting and tracking of tropical cyclones has become a sophisticated process using Earth observation instruments from land, sea, air, and space.
And new tools are becoming available every day, sometimes in unexpected ways.
Hurricane Igor was the 2010 storm that began off the African coast and eventually caused so much damage to Newfoundland that the name ‘Igor’ was retired. It was Igor that showed just how well a satellite designed to track dirt and salt could provide information on tropical cyclones.
The European Space Agency’s Soil Moisture and Ocean Salinity satellite was built with a microwave radiometer to gauge radiation being emitted from the surface of the Earth. According to the ESA, scientists can use images collected by the radiometer to determine how much water is held in soil or how much salt is in the surface water of oceans. Because the SMOS sensor works on a lower microwave frequency than others, it can detect radiation changes over oceans being churned up in tropical storms, even as the extreme weather hinders accuracy of other satellites.
Researchers tested the idea during Hurricane Igor, and the findings show that the sensor could help improve the accuracy of tropical cyclone forecasting. It also showed that salinity in the surface waters changes in the wake of a hurricane, “the first time that such changes have been detected from space.”
NASA’s Unmanned Tracks
While ESA continues to explore new ways of using the SMOS sensors, NASA is experimenting with sensing storms for longer periods of time by using unmanned aircraft, or drones.
When the 2012 hurricane season reaches its peak in September and October, NASA says it will have two Global Hawk unmanned aircraft ready to fly out of its facility at Wallops Island, Va., each carrying specialized instruments.
The advantage of the unmanned aircraft is that they can fly at altitudes greater than 60,000 feet while staying airborne for up to 28 hours, which would be almost impossible for piloted aircraft. One Global Hawk will be outfitted to examine the large-scale environment of a storm, while the other aircraft will be able to examine the storm’s inner workings (such as the eyewall, rainband wind, and precipitation level).
With the information, scientists may be able to better understand hurricane formation and intensity changes.
Challenges from Sky to Sea
Earlier this year, alarms were sounded that hurricane tracking could face some serious challenges over the next decade as aging satellites fall into disrepair.
One new satellite being prepared may be able to do the job of several. The “super sophisticated weather satellite,” known as GOES-R (Geostationary Operational Environmental Satellite, R Series) is being built by NASA with a launch target of 2016. Senior hurricane specialist Jack Beven told the Sun-Sentinel in Florida that the satellite would provide about 30 times more data than current satellites.
Current satellites can provide storm imagery once every 15 to 30 minutes, zooming to within 0.6 of a mile. But, according to Beven, the GOES-R will be able to provide images every 30 seconds and zoom to within 0.3 of a mile from the storm.
AJ Plunkett is a freelance writer in Virginia with experience in covering defense and aerospace industries as well as the military. AJ blogs via Contently.com.