Help Meteorologists Launch a Real Weather Balloon

AERI

ARM

MADISON, WI, March 31, 2004—Help meteorology graduate students launch a weather balloon at 3:30 p.m., Saturday, April 3 from the roof of the Atmospheric, Oceanic and Space Sciences Building. The building is located at 1225 W. Dayton St., just two blocks from the Engineering Building, the main site of UW–Madison's 2004 Science Expeditions. Come for the 3:15 tour, given by the Space Science and Engineering Center, and stay for the launch.

Weather balloons, or radiosondes, as they are technically called, are the primary means that meteorologists traditionally use to learn more about the immediate state of a column of air, or, what’s in the atmosphere right above your head. The radiosonde is actually a collection of instruments that measure pressure, temperature, and humidity. The packet of instruments is attached to a large helium-filled balloon. When released, the balloon floats into the atmosphere and, using a radio transmitter, sends the measurements to a ground station.

The name “radio-sonde” refers to the radio transmitter attached to a package of instruments designed to “sound” the atmosphere. On Saturday, the ground station will be a laptop computer in the building’s penthouse. You can watch as the data is received.

It is also possible to measure wind speed and direction by tracking the balloon. Attaching instruments to a balloon is a relatively inexpensive, efficient means of measuring the atmosphere, although it can go astray.

Small prizes will be given for the best estimate of how high the balloon will get before it breaks.

Ed Hopkins, Wisconsin’s State Climatologist, provides information about radiosondes.

The company who makes most radiosondes, including the one to be used Saturday is Vaisala, in Finland. You can find out more about the instrument on the Web site of the Department of Energy’s Atmospheric Radiation Measurement program. SSEC contributes to this project with their Atmospheric Emitted Radiance Interferometer (AERI), an instrument that can retrieve similar types of measurements as the radiosonde but never needs to leave the ground. An AERI will be operating at the balloon launch site on the top of the building.

The Space Science and Engineering Center, located in the building, is giving roof tours starting in the building lobby at 1 p.m., 1:45 p.m., 2:30 p.m. and 3:15. If you arrive early, you will find Mars-related and other activities to do in the lobby.

--T.Gregory and R.Holz

31 March 2004 TG