In this paper, we use the Rayleigh lidar in order to give an overview of the gravity wave activity at a northern middle-latitude station at Haute-Provence Observatory (43.93°N, 5.71°E). In order to have access to perturbations with short time and vertical scales, at least in a statistical sense, we analyze raw lidar signals with a variance method. Sixteen years of lidar data sets are analyzed in this study. The results of the variability, climatology, and seasonal changes are reported. We observe night-to-night variability in gravity wave potential energy, which follows a lognormal distribution with a standard deviation ranging between 0.50 and 0.58 (base 10 logarithm). A monthly distribution of gravity waves is also obtained in the upper stratosphere and mesosphere. In the 30-50 km altitude range (the upper stratosphere), an annual cycle is clearly found with a maximum in winter and a minimum in summer. An annual cycle in the lower mesosphere is also observed with maximum in winter. In the upper mesosphere, a semiannual cycle is found at~75 km. At this altitude, the maximum gravity wave activity occurs in winter and in summer. A more pronounced summer maximum is observed (+25%). The summer maximum at Haute-Provence Observatory in the upper mesosphere is probably due to oblique propagation. Looking at the seasonally averaged profiles, it is possible to observe the preferential altitudes of energy dissipation. Gravity waves are dissipating abovẽ 70 km during all seasons, but there is relatively little dissipation at lower altitudes.

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.