EGU2020-4171
https://doi.org/10.5194/egusphere-egu2020-4171
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

A different perspective on how parameterized orographic gravity waves influence atmospheric transport and dynamics in current generation global climate models

Harald Rieder1, Petr Šácha1,2, Roland Eichinger3,4, Aleš Kuchař2, Nadja Samtleben5, Petr Pišoft2, and Christoph Jacobi5
Harald Rieder et al.
  • 1University of Natural Resources and Life Sciences, Vienna (BOKU), Institute of Meteorology and Climatology, Vienna, Austria (harald.rieder@boku.ac.at)
  • 2Charles University, Faculty of Mathematics and Physics, Department of Atmospheric Physics, Prague, Czech Republic
  • 3Ludwig Maximilians Universität, Institut für Meteorologie, Munich, Germany
  • 4Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Germany
  • 5University of Leipzig, Institute for Meteorology, Leipzig, Germany

In the atmosphere, internal gravity waves (GWs) are a naturally occurring and ubiquitous, though intermittent phenomenon. In addition, GWs (especially orographic; OGWs) are asymmetrically distributed around the globe. In current generation global climate models (GCMs), GWs are usually smaller than the model grid resolution and the majority of their spectrum therefore must be parameterized. To some extent, the intermittency and asymmetry of a spatial distribution of the resulting OGW drag (OGWD) is present also in GCMs. As the GW parameterization schemes in GCMs are usually tuned to get the zonal mean climatology of particular features right, an important question emerges: what kind of influence do GW parameterizations have on the individual models atmosphere locally? Here we focus on answering this question regarding the impact of spatiotemporally intermittent OGW forcing in the extra-tropical lower stratosphere region (LS). The LS region is characterized by a strong interplay of chemical, physical and dynamical processes. To date, the representation of this dynamically active region in models frequently mismatches observations. Although we can find a climatological maximum of oGWD in the LS, the role of OGW forcing for the transport and composition in this region is poorly understood. We combine observational evidence, idealized modeling and statistical analysis of GCM outputs to study both the short-term and long-term model response to the OGW forcing. The results presented will question the relationship between the advective part of the Brewer- Dobson circulation and the zonally asymmetric GW forcing, and a so-far neglected link between oGWD and large-scale quasi-isentropic stirring will be discussed.

How to cite: Rieder, H., Šácha, P., Eichinger, R., Kuchař, A., Samtleben, N., Pišoft, P., and Jacobi, C.: A different perspective on how parameterized orographic gravity waves influence atmospheric transport and dynamics in current generation global climate models, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4171, https://doi.org/10.5194/egusphere-egu2020-4171, 2020

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