Grenade sounding

From Glossary of Meteorology

grenade sounding

A method of atmospheric sounding in which wind velocities and temperatures are inferred, as functions of height to about 90 km, from analysis of the speed of travel of sound waves from a series of grenades fired at height intervals of a few kilometers from an ascending meteorological rocket.

The sounds of detonation are received at an array of microphones on the ground. The position and time of the grenade bursts are determined by optical or radio means.