Quasi-observational climatology of the gravity wave forcing in the stratosphere.

Gravity waves contribute to the energy and momentum transport and budget in the atmosphere, in the stratosphere in particular. Observations and simulations of their effects poses significant challenges due to diverse spatial and temporal scales involved. Despite these challenges, incorporating the effects of gravity waves is essential for global climate and weather prediction models. This study presents a first climatological analysis of resolved gravity waves based on the ECMWF's ERA5 reanalysis and their impacts on the mean flow over more than 43 years. The spatiotemporal distribution of the gravity wave drag is investigated, short and long-term variability analysed locally above the hotspots and in a zonal mean. The results match very well the theoretically assumed properties of gravity waves in the atmosphere, which is very encouraging with respect to the question, how realistic are resolved gravity waves in reanalyses. Our research enhances our understanding of gravity wave drag in the stratosphere and can be used for informing and validating the gravity wave parameterization schemes in climate models.