Long-term Observations of Gravity Wave Energy and Momentum Fluxes in the Middle Atmosphere from SABER/TIMED satellite

Gravity waves are a fundamental component of middle-atmosphere dynamics, playing a key role in the redistribution of momentum and energy and thereby shaping the thermal structure and large-scale circulation of the stratosphere and mesosphere. Through their interaction with the mean flow, gravity waves contribute to processes such as the driving of the residual circulation, seasonal variability, and coupling between atmospheric layers. Despite their recognised importance, gravity wave activity remains highly variable in space and time and is still poorly represented in global circulation and climate models, highlighting the need for long-term observational constraints. This work aims to quantify gravity wave contributions in the stratosphere and lower mesosphere using temperature perturbations derived from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument over the period 2002–2025. Gravity wave potential energy, momentum fluxes, and wave amplitudes are used to construct climatologies describing the spatial structure and temporal variability of gravity wave activity. The analysis focuses on the Northern Hemisphere winter, when enhanced gravity wave potential energy is observed in the SABER seasonal climatology. Beyond seasonal variability, the ongoing analysis investigates interannual and long-term variations in gravity wave activity, with the aim of exploring potential links to changes in large-scale circulation and background conditions. To complement the satellite-based observations, wind perturbation variances derived from the Esrange meteor radar (68°N, 21°E) are used to characterise gravity wave signatures at high northern latitudes over the period 1999–2024. By combining long-term satellite and ground-based observations, this work seeks to improve the observational characterisation of gravity wave variability in the middle atmosphere.