Weather Whys; Balloons

This is weather wise. Twice a day balloons go up at weather stations all over the United States and around the world. They carry instrument packages which give meteorologists important information about weather conditions in the atmosphere. Those packages are called radio-sunds, and the data they transmit to ground stations provide the basis for weather forecasts. The typical radio-sund being used by the National Weather Service is a white box about the size of a half-gallon milk carton. The box hangs from a string tied to a weather balloon. And as the balloon rises in the atmosphere, the radio-sund measures air pressure, air temperature and humidity, and continuously transmits the readings back to a weather station by means of a small radio transmitter. The information gathered can give meteorologists a better idea of how a weather is developing. For example, when your TV weathercaster shows you an upper-level trough, it was radio-sund data that showed meteorologists where that was.

But besides the three main measurements of pressure, temperature, and humidity, radio suns also provide information about the winds and how they're blowing at various heights. Eventually, after climbing high in the atmosphere, the weather balloon breaks, and the radio-sund unit attached to a small parachute, falls gently to the ground. Even though each unit only costs about $50, the National Weather Service hopes that whenever people find one of the devices in their yard, they'll turn them in so they can be reused. Weather-wise is a production of the Center for Analysis and Prediction of Storms at the University of Oklahoma, established in 1989 by the National Science Foundation for research on local and regional prediction of storms. Our producer is Steve Patrick, our executive producer, Karen Hope. Our writer is Christine Harbour, and our editor is Brian Walkie. For Weather-wise, I'm Drew Barlow.