Abstract In September and October 2005, the Strateole/Vorcore campaign flew 27 superpressure balloons from McMurdo, Antarctica, into the stratospheric polar vortex. Long-duration flights were successfully achieved, 16 of those flights lasting for more than 2 months. Most flights were terminated because they flew out of the authorized flight domain or because of energy shortage in the gondola. The atmospheric pressure (1-Pa precision) was measured every minute during the flights, whereas air temperature observations (0.25-K accuracy) and balloon positions (absolute GPS observations, 10-m accuracy) were obtained every 15 min. Fifteen-minute-averaged horizontal velocities of the wind were deduced from the successive balloon positions with a corresponding accuracy ≲0.1 m s−1. The collected dataset (more than 150 000 independent observations) provides a thorough high-resolution sampling of the polar lower stratosphere in the Southern Hemisphere from its wintertime state up to the establishment of the summer ci...

The STRATÉOLE experiment is designed to study the wintertime Antarctic lower stratosphere polar vortex and its springtime breakdown. To this end, it is planned to fly a large number (around 200) of long-lived (3 months), small isopycnic drifting balloons instrumented with temperature and pressure sensors, GPS and transmitters. The main goal of STRATÉOLE experiment is to provide an unprecedented documentation of the wind field in the vicinity of the vortex edge in order to study vortex porosity and erosion, filamentation and mixing properties of the air masses. In addition, by the use of other sensors on some gondola, like radiometers and tuneable laser diodes, STRATÉOLE will also provide in-situ and/or column-integrated trace species measurements (like NO2, O3, CH4, H2O, aerosols...) and information on the radiation budget of the Antarctic lower stratosphere during this period. This will permit to obtain a better understanding of mechanisms responsible for ozone depletion occurring during the springtime vortex dilution.

Un hygrometre a point de rosee pour la mesure de l'humidite atmospherique au moyen de ballons a ete developpe. Deux instruments ont ete utilises lors de deux vols de ballons stratospheriques, l'altitude du plafond etait de 16 km et des points de rosee de l'ordre de −80 o C y ont ete mesures

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.