What in the World is a Radiosonde?
A radiosonde contains sensors which transmit radio signals to a ground tracking station. The instrument is powered by a small dry-cell battery and is housed in a casing of Styrofoam the size of a shoe box. A Hydrogen-filled balloon provides the lift needed to carry the radiosonde upward, and a three dimensional observation of pressure, humidity, and air temperature is taken. Wind speed and direction are calculated by figuring the instrument’s position relative to the ground tracking station. The radiosonde rises to heights up to 20 miles above the Earth’s surface and then a parachute carries the reusable instrument to the ground after the balloon bursts. Data that are received by a ground station is transmitted by phone modem to a supercomputer center in Washington D.C. A national and worldwide network of sites that take upper air observations allow construction of forecast maps, graphics, and charts. Weather forecasters attempted to collect data at levels above the surface in the earl
