The observation of the upper air usually involves the measurement of temperature and humidity versus height, and upper wind. The measurement is usually carried out using a radiosonde, an instrument intended to be carried by a balloon into the atmosphere.

Upper air measurements are vital to aviation and artillery operations.

The altitude that can be reached is about 25 km. The sonde is drifting away with the wind, and transmits to a ground station. The range of transmission is about 200 km. The ground station normally must also track the balloon. This process is performed using a theodolite.

The main suppliers of radiosondes are Vaisala, Intermet Systems and Graw.

Theodolites can also be obtained from Breithaupt.

High altitude balloons see Raven Industries.

For hydrogen generators, see Proton Energy

See also Balloon and Boundary Layer.