Gravity Wave Interactions in the Global Atmosphere (GWING)

Hauke Schmidt, Max Planck Institut für Meteorologie (MPI-M), Hamburg (Coordinator)
Günther Zängl, Deutscher Wetterdienst (DWD), Offenbach
Elisa Manzini, Max Planck Institut für Meteorologie (MPI-M), Hamburg

Claudia Stephan (MPI), Sebastian Borchert (DWD); Phase 1:Guidi Zhou (MPI)

Further contributions from:
Ulrich Achatz, Goethe Universität Frankfurt, Frankfurt/Main
Erich Becker, Leibniz Institute for Atmospheric Physics, Kühlungsborn

Internal gravity waves (GWs) link different layers of the atmosphere from the troposphere to the thermosphere and drive the large-scale circulation of the middle atmosphere. However, many of the processes from their generation via propagation to dissipation are still incompletely understood and due to their small (often sub-grid) length scale they are poorly represented in numerical weather prediction and climate models. GWING is one of the projects of the research unit MS-GWaves that aims at advancing our understanding of the above mentioned multiscale dynamical processes involving atmospheric GWs with the ultimate goal to develop a unified parameterization of sub-grid scale GW processes (and their effects) from the sources to the dissipation. To contribute to this, the central goal of the project GWING is the development and application of the UA-ICON atmospheric general circulation model. With UA-ICON, the GWING project is integrating the new knowledge generated by the whole MS-GWaves unit. In the 2nd phase of GWING we will focus on the following overarching scientific questions:a) What is the relevance of GW features neglected in classical parameterizations, i.e. horizontal propagation, non-instantaneous propagation, and wave transience-mean flow interactions.b) What is the role of gravity waves for the global atmospheric circulation and its variability?To answer these questions, we will use UA-ICON globally at both GW-permitting resolution and coarse resolution but with a state-of-the-art WKB GW-parameterization (MS-GWaM). Furthermore, we will continue to simulate and analyse episodes with locally highly resolved, GW-resolving nests. The model simulations will be combined with the observational knowledge from the partner projects. The major UA-ICON development goals in phase 2 of GWING are therefore the implementation of MS-GWaM (developed in partner project 3DMSD), the implementation of physics-based sources (jointly with partner projects SV and 3DMSD), and the improved treatment of GWs at high model resolutions. Using the different configurations of UA-ICON will finally allow to assess the importance of so far neglected features, i.e. to answer our first overarching question. A specific objective for GWING is this assessment for the situation during SSWs which provide rapidly changing and zonally inhomogeneous propagation conditions for GWs, and therefore may be particularly prone to effects of non-instantaneous propagation and wave transience-mean flow interactions. With respect to the 2nd overarching question, the role of GWs for the global atmospheric circulation, besides SSWs, we will focus on a) the role of GWs and model extension to the upper atmosphere for circulation changes under global warming, and b) the role of GWs for weather forecasting skill.

Detailed Overview