Drifting Skyward

The eastern tropical Atlantic Ocean is out of range for U.S. hurricane-hunter aircraft, and forecasters have little skill predicting which systems brewing there will develop into hurricanes, atmospheric scientists say. So, to find out how some of the most dangerous hurricanes form, U.S. and French researchers are launching large, specialized balloons carrying nearly 300 instruments over wide swaths of Africa and the Atlantic Ocean.

The first launch of a balloon with its instruments, called a driftsonde, took place at Zinder, Niger, on Aug. 28. Some seven more driftsondes will be released from Zinder through late September, coinciding with the peak period of hurricane formation over the tropical Atlantic.

Each balloon will drift from Africa toward the Caribbean at heights of around 65,000-70,000 feet, where light easterly winds prevail. Twice a day, each balloon will release an instrument known as a dropsonde that falls by parachute, sensing the weather conditions during its 20-minute descent and sending data back to the balloon and then to the researchers by satellite.

--LiveScience Staff

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Credit: NCAR