Toward an improved representation of middle atmospheric dynamics thanks to the ARISE project

This paper reviews recent progress toward understanding the dynamics of the middle atmosphere in the framework of the Atmospheric Dynamics Research InfraStructure in Europe (ARISE) initiative. The middle atmosphere, integrating the stratosphere and mesosphere, is a crucial region which influences tropospheric weather and climate. Enhancing the understanding of middle atmosphere dynamics requires improved measurement of the propagation and breaking of planetary and gravity waves originating in the lowest levels of the atmosphere. Inter-comparison studies have shown large discrepancies between observations and models, especially during unresolved disturbances such as sudden stratospheric warmings for which model accuracy is poorer due to a lack of observational constraints. Correctly predicting the variability of the middle atmosphere can lead to improvements in tropospheric weather forecasts on timescales of weeks to season. The ARISE project integrates different station networks providing observations from ground to the lower thermosphere, including the infrasound system developed for the Comprehensive Nuclear-Test-Ban Treaty verification, the Lidar Network for the Detection of Atmospheric Composition Change, complementary meteor radars, wind radiometers, ionospheric sounders and satellites. This paper presents several examples which show how multi-instrument observations can provide a better description of the vertical dynamics structure of the middle atmosphere, especially during large disturbances such as gravity waves activity and stratospheric warming events. The paper then demonstrates the interest of ARISE data in data assimilation for weather forecasting and re-analyzes the determination of dynamics evolution with climate change and the monitoring of atmospheric extreme events which have an atmospheric signature, such as thunderstorms or volcanic eruptions

Dynamics and Transport in the Middle Atmosphere Using Remote Sensing Techniques from Ground and Space

International audienceThe 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

Temperature trends observed in the middle atmosphere and future directions

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