Daily Archives: April 4, 2016

Meteorologists monitor the atmosphere above the Earth’s surface by using a radio-equipped weather instrument package carried aloft by a helium-filled “weather balloon.” These instrument packages are called radiosondes (“sonde” is French for “probe”).

Radiosondes measure vertical profiles of air temperature, relative humidity and pressure from the ground all the way up to about 19 miles above. At low air pressures in the stratosphere, the balloon expands so much that it explodes and the radiosonde drifts back to the ground underneath a small parachute. Continue reading →