Strateole Program
High-altitude balloon program to study the tropopause

Strateole-2 is a French-US project to study climate processes in the Tropical Tropopause Layer (TTL) and in the lower stratosphere. The project originality pertains to the use of CNES superpressure balloons, capable of drifting for several months between 18 and 20 km altitude. Strateole-2 will release a total of nearly 20 long-duration balloons in two separate campaigns between 2019 and 2024.
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Launch Dates:
Campaign 1: November 2020 and April 2021
Campaign 2: November 2023 and April 2024
Lead Institution: Centre National d’Etudes Spatiales (CNES)
Partners: Laboratory for Atmospheric and Space Physics, National Science Foundation, National Oceanic and Atmospheric Administration, Scripps Institution of Oceanography, NorthWest Research Associates, Atmospheric Sciences and Climate Italy, National Atmospheric Research Laboratory India, University of Adelaide Australia
To predict climate better, we first need to understand the mechanisms underlying transport of water vapour from the troposphere to the stratosphere, driven by large-scale convective motions associated with cloud masses in equatorial regions, and to learn more about atmospheric undulations in these regions, especially those generated by these powerful convective systems.
Strateole 2 will deliver data on key parameters driving the dynamic and physical processes affecting climate in the tropics, as well as at global scale as far as the polar regions.
Strateole 2 is a valuable addition to existing observation assets, providing measurements at high spatial and temporal resolution to effectively complement data acquired at fixed points on the ground and at fixed but not very frequent times from space-based instruments.
The superpressure balloons will observe for three months on average the mechanisms driving the formation of high clouds and the composition of the atmospheric layers of the equatorial zone: the troposphere and stratosphere, and more specifically the boundary between the two, the tropopause.
The project will also investigate the east-west cycles of the Quasi-Biennial Oscillation (QBO), a change in the direction of stratospheric winds at the equator which follows a cycle of 28 months or so on average. Strateole 2 will help to better understand and predict this phenomenon.
The Stratéole 2 data set is publicly available to anyone who is interested. To access all the RACHuTs, LPC and FLOATS raw and processed data please contact Lars Kalnajs for a password, then click the Pre Stratéole 2 Data link. This process has been implemented to gather statistics on how the data is being used as well as to establish contact with data users to provide further assistance and tools for processing and analyzing the data set.
Alternatively, the broader Stratéole 2 data set can be accessed on the IPSL Data Server.