Dynamics and Transport in the Middle Atmosphere Using Remote Sensing Techniques from Ground and Space
Résumé
The middle atmosphere is generally defined as the region of the atmosphere located between the tropopause (8–17 km) and the mesopause (85–90 km). It includes the stratosphere, where the ozone layer takes place, and the mesosphere. The temperature and wind structure of this region is mainly driven by radiative processes (mainly on of solar radiation by ozone and infrared cooling by CO2) and dynamic processes (propagation and breaking of planetary and gravity waves, meridional circulation from equator to poles in the stratosphere, and from summer pole to winter pole in the mesosphere). A good knowledge of these processes is required to understand the transport of constituents playing a role in the photochemistry of stratospheric ozone and the heat budget of the middle atmosphere determining its thermal structure. In-situ measurements at these high altitudes are not easy to perform and several remote sensing techniques have been developed to observe these regions from the ground and from space, among them infrasound measurement is a promising one. This article presents the main characteristics of dynamics and transport in the middle atmosphere and gives a review of the remote sensing techniques used to observe this region in complement to infrasound detection: lidars, radars, infrared and microwave sounders, and GNSS radio-occultation.