Global Circulation and Climate


Group Leader: Hauke Schmidt


The tropical upper troposphere is a fascinating part of the atmosphere where composition and heating, from convection and radiation, set the thermal structure which in turn influences large-scale circulation. Work in our group focusses on understanding the different contributions to the lapse rate in this region, its implications, and how it might change in a warming climate. Beyond this focus we are more generally interested in better understanding how atmospheric diabatic processes and circulation interact on the global scale and how this shapes Earth's climate. Current topics we are working on include the question of the origin of the hemispheric symmetry of outgoing solar radiation, the role of gravity waves for large-scale circulations, and the appropriateness of present-day climate models for studying processes of our interest.

An important step for a better conceptual understanding of tropical stability was the development of the 1D-radiative convective equilibrium model “konrad”. We see this tool as the simplest element of a model hierarchy that also includes the convection-resolving Sapphire configurations of ICON, for instance to test the limits of assumptions on convection, and the Ruby-type ICON configurations, to study implications for global circulation. Likewise, to establish a model hierarchy enabling us to better understand the role of composition we have implemented the computationally cheap, linear Cariolle ozone scheme in ICON and assessed its scientific usefulness. This adds to earlier developments of simplified representations of composition, the Simple Plumes and EVA approaches for tropospheric and volcanic aerosols.

The "Global Circulation and Climate" group exists since August 2018. Some of its members were in the "Middle and Upper Atmosphere" and "Climate Dynamics" groups before. For past scientific activities see the legacy websites of those groups.


Selected Publications:

Dacie, S., Kluft, L., Schmidt, H., Stevens, B., Buehler, S., Nowack, P., Dietmüller, S., Abraham, L. & Birner, T. (2019). A 1D RCE study of some factors which might affect the tropical tropopause layer and surface climate. Journal of Climate, 32, 6769-6782. doi:10.1175/JCLI-D-18-0778.1

Fiedler, S., Crueger, T., D'Agostino, R., Peters, K., Becker, T., Leutwyler, D., Paccini, L., Burdanowitz, J., Buehler, S., Uribe, A., Dauhut, T., Dommenget, D., Fraedrich, K., Jungandreas, L., Maher, N., Naumann, A., Rugenstein, M., Sakradzija, M., Schmidt, H., Sielmann, F., Stephan, C., Timmreck, C., Zhu , X. & Stevens, B.(2020). Simulated tropical precipitation assessed across three major phases of the Coupled Model Intercomparison Project (CMIP). Monthly Weather Review, 148, 3653-3680. doi:10.1175/MWR-D-19-0404.1

Meraner, K., Rast, S. & Schmidt, H.(2020). How useful is a linear ozone parameterization for global climate modeling?. Journal of Advances in Modeling Earth Systems, 12: e2019MS002003. doi:10.1029/2019MS002003
Stephan, C., Strube, C., Klocke, D., Ein, M., Hoffmann , L., Preusse, P. & Schmidt, H.(2019). Gravity waves in global high-resolution simulations with explicit and parameterized convection. Journal of Geophysical Research - Atmospheres, 124, 4446-4459. doi:10.1029/2019MS002003

Stephan, C., Strube, C., Klocke, D., Ein, M., Hoffmann, L., Preusse, P. & Schmidt, H.(2019). Intercomparison of gravity waves in convection-permitting models. Journal of the Atmospheric Sciences, 76, 2739-2759. doi:10.1175/JAS-D-19-0040.1

Stephan, C. C., Schmidt, H., Zülicke, C., & Matthias, V. (2020). Oblique gravity wave propagation during sudden stratospheric warmings. Journal of Geophysical Research: Atmospheres, 125(1), e2019JD031528.