Abstract
A new kind of sounding from a free-floating balloon has been designed to study the two-dimensional structure of a shallow layer in the atmosphere. This type of sounding adds another dimension to the horizontal quasi-Lagrangian sounding made with superpressure constant level balloons. To sound the two-dimensional structure of an atmospheric layer, a light winch set just below the balloon raises and lowers a platform supporting meteorological sensors. This platform repeatedly traverses a shallow layer (400 m) of the stratosphere. A complete scanning of the layer lasts 30 min, and the pressure, air temperature and differential wind (intensity and direction) between the level of the platform and that of the balloon are measured every 10 m in height. All the equipment is presented and described and the first flight successfully performed in 1976 is described. The data recorded during this 2 h flight show that the dynamics of mesoscale motions occurring in the stratosphere can be studied with this two-dimensional sounding technique.
