Meteorological (MET) Rockets

A small rocket system used for extending observations of the atmosphere above feasible limits for balloon-borne and ground-based instruments.

Exploration of the middle atmosphere (20–95 km altitude) through use of these systems (also known as rocketsondes) matured in the 1960s into a highly productive source of information on atmospheric structure and dynamics. Many thousands of small meteorological rockets have been launched in a coordinated investigation of the wind field and the temperature and ozone structures in the middle atmosphere region at 25–90 km altitude. See e.g. our studies of the mesospheric thermal structure.
These data played a key-role in the understanding of the middle atmosphere, yielding strong evidence that this region is primarily driven by dynamics. The main techniques used at IAP are so called Falling Spheres (FS) and chaff clouds.

Inflated sphere in the atmosphere

A small rocket delivers an inflatable sphere (FS) or a cloud of small pieces of foil (chaff) to heights of 90–120 km. The sphere is inflated or the cloud is ejected at apogee and falls down. It experiences horizontal advection by the neutral winds and deceleration by friction with neutral gas. The sphere/cloud is precisely tracked by a ground-based radar.

Principle of the FS/CHAFF technique

From the first derivative of the trajectory one can derive neutral winds. From the second derivative (i.e., deceleration), one can derive the neutral air density.