Gravity wave group

Our group was founded in 2023 and is funded by the Czech Gramt Agency Junior Star project 23–04921M „Unravelling climate impacts of atmospheric internal gravity waves“. We focus on aspects of atmospheric dynamics and transport related to internal gravity waves in the atmosphere and on the representation of gravity waves in global climate and forecast models using so-called parameterizations. Using a combination of theory, numerical model hierarchy experiments, satellite observations, and analysis of existing data (e.g., reanalyses), we aim to rethink and advance our understanding of the climate impacts of gravity waves in the atmosphere and contribute to improving the way they are parameterized in climate models. Our group is fully involved in international research initiatives (APARC Gravity Wave Activity, DynVar, A-RIP, TEAMx) and collaborates with researchers and research centres around the world. We also organize an annual international workshop on gravity waves.

Group leader: RNDr. Petr Šácha, Ph.D.
Postdoc: Mgr. Anahí Villalba Pradas, Ph.D.
Doctorands: Mgr. Zuzana Procházková, Mgr. Radek Zajíček, MSc. Massimo Martina, Mgr. Dominika Hájková

The group's research topics include:

• Studying the interaction between parameterized gravity waves drag and waves on synoptic and planetary scales in models.
• Evaluating the realism of this interaction in models fully resolving gravity waves.
• A reassessment of the known effects of gravity waves in gravity wave resolving models.
• Development of gravity wave parameterizations for global climate models.

Research tools:

• Theoretical research on gravity waves and interaction with background flow.
• Numerical experiments with Lagrangian (FLEXPART), idealistic (ICAR), detailed regional (WRF) and global chemistry-climate (EMAC) models.
• Existing data such as reanalyses (ERA5), satellite observations (AIRS, GPS RO) and modelling initiatives (DYAMOND initiative, CMIP6).

International collaborations

• APARC GW activity (https://www.aparc-climate.org/activities/gravity-waves/)
  • membership.
• APARC DynVarMIP (https://www.aparc-climate.org/activities/dynamical-variability/)
  • coordination of the request for information on gravity waves for the upcoming international modeling initiative CMIP7
• APARC Reanlysis Intercomparison Project (https://s-rip.github.io/)
  • co-leading a thematic team focusing on gravitational waves in the atmosphere
• TEAMx programme and observational campaign (https://www.teamx-programme.org)
  • co-management of the group with a focus on the dynamics and interaction of the flow with mountain ranges

Publications

• Šácha, P., Zajíček, R., Kuchař, A., Eichinger, R., Pišoft, P., & Rieder, H. E. (2024). Disentangling the advective Brewer‐Dobson circulation change. Geophysical Research Letters, 51, e2023GL105919. https://doi.org/10.1029/ 2023GL105919
• Fujiwara, M., Martineau, P., Wright, J. S., Abalos, M., Šácha, P., Kawatani, Y., Davis, S. M., Birner, T., and Monge-Sanz, B. M.: Climatology of the terms and variables of transformed Eulerian-mean (TEM) equations from multiple reanalyses: MERRA-2, JRA-55, ERA-Interim, and CFSR, Atmos. Chem. Phys., 24, 7873–7898, https://doi.org/10.5194/acp-24-7873-2024, 2024.
• Hájková, D., and Šácha, P. Parameterized orographic gravity wave drag and dynamical effects in CMIP6 models. Climate Dynamics, 2023.https://doi.org/10.1007/s00382–023–07021–0.
• Procházková, Z., Kruse, C. G., Alexander, M. J., Hoffmann, L., Bacmeister, J. T., Holt, L., Wright, C., Sato, K., Gisinger, S., Ern, M., Geldenhuys, M., Preusse, P., & Šácha, P. (2023). Sensitivity of mountain wave drag estimates on separation methods and proposed improvements. Journal of the Atmospheric Sciences. https://doi.org/10.1175/JAS-D-22-0151.1.