From Glossary of Meteorology


A method of winds-aloft observation; that is, the determination of wind speeds and directions in the atmosphere above a station.

It is accomplished by recording the elevation and azimuth angles of the balloon at specified time intervals while visually tracking a radiosonde balloon with a theodolite. A rabal is basically the
same as a pilot-balloon observation, except that the height data are derived from the radiosonde observation rather than from an assumed balloon ascension rate.