April 1, 2007 For decades, meteorologists have launched balloons to measure and track weather patterns. Now, these balloons are helping tropical forecasters better pinpoint the motion and severity of forming hurricanes. The balloon releases small capsules about the size of a water bottle called driftsondes. As a capsule drifts to earth, it transmits temperature, wind and pressure data to a satellite.
When hurricanes threaten, time is critical in making forecasts to save lives and property. When a hurricane strikes, forecasters need all the help they can get to predict just how bad it'll be. And scientists at the National Center for Atmospheric Research (NCAR) have taken another step in better predicting how strong a hurricane will be and where it will strike.
For decades, meteorologists have launched balloons to measure and track weather patterns. Now, these balloons are helping tropical forecasters better pinpoint the motion and severity of forming hurricanes.
A balloon launch in Niger, Africa, tracked hurricane formation information in 2006 that helped save lives in the United States. American scientists were ecstatic. "We actually opened a bottle of champagne in Paris when, when the gondola got over the ocean," Senior Scientist David Parsons, of NCAR in Denver, tells DBIS.
The balloon releases small capsules about the size of a water bottle called driftsondes. As a capsule drifts to earth, it transmits temperature, wind and pressure data to a satellite. The capsules are good for only one free fall and cost $300 to $400 each.
One balloon in the experiment gathered and transmitted information for 18 days after being released.
"Events with a damage of a billion dollars per event are getting to be much more common. So really a few thousand dollars spent on these measurements or even millions spent on research can be very cost effective," Parsons says.
Up to 1,500 driftsondes are expected to be released between April 2007 and December 2008.
The American Meteorological Society contributed to the information contained in the TV portion of this report.
BACKGROUND: Last year, a caravan of weather balloons made meteorological history by marking the first-ever deployment of a new airborne weather-observing platform, called a driftsonde. Driftsondes are weather instruments connected to a balloon that “drifts” through the atmosphere collecting data. Nearly 300 gathered data from critical regions in the atmosphere that serve as breeding grounds for some of the worst hurricanes in the US.
HOW IT WORKS: The driftsonde setup includes a super-pressured balloon that slowly inflates as it reaches the upper atmosphere; a parachute that allows the unit to descend safely when needed; a corner reflector to help airplane radar spot the unit and avoid a collision; a gondola holding communications equipment for tracking; and another gondola holding 35 weather measurers. The tracking system also receives assistance from the Global Positioning System (GPS). The weather measurers are strewn along the path the balloon takes in the upper atmosphere, released about twice a day. As they fall, they sense the weather conditions during the 20-minute descent, and this data is radioed back to the balloon, and then transmitted via satellite to the researchers at the National Center for Atmospheric Research (NCAR). The new system is called Miniature In-situ Sounding Technology (MIST), and it is a highly compact instrument, about the size of a small bottle of water and weighing a mere 5 ounces.
CHALLENGES MET: Each driftsonde had to be able to withstand several days of extreme cold in the upper atmosphere, averaging minus-80 degrees Fahrenheit, as well as the intense sunlight typical of the high, thin stratosphere. Using the balloons also had to be affordable and practical, so the system required low-cost, lightweight, off-the-shelf instruments that could operate reliably in low pressure and in temperature extremes, while consuming very little power. Because of their flexible and relatively inexpensive nature, scientists believe that driftsondes may soon become a very popular way to monitor and study many types of weather across the globe – even in very far-off regions.