Nedisipativní efekty vnitřních gravitačních vln v atmosféře, jejich diagnostika a reprezentace v atmosférických modelech.

• Název práce v češtině: Nedisipativní efekty vnitřních gravitačních vln v atmosféře, jejich diagnostika a reprezentace v atmosférických modelech.
• Název v anglickém jazyce: Non-dissipative effects of internal gravity waves in the atmosphere, their diagnostics and representation in atmospheric models.
• Klíčová slova: Vnitřní gravitační vlny|Atmosféra|Oscilující trajektorie|Klimatické modely|Propagace vln
• Klíčová slova anglicky: Internal Gravity Waves|Atmosphere|Oscillating Trajectories|Climate Models|Wave Propagation
• Akademický rok vypsání: 2024/2025
• Typ práce: disertační práce
• Ústav: Katedra fyziky atmosféry (32-KFA)
• Vedoucí / školitel: RNDr. Petr Šácha, Ph.D.

Zásady pro vypracování

Within the thesis, a purely theoretical work concerning the development of diagnostics of non-dissipative GW effects will be combined with high-resolution GW resolving modeling aligned with other TEAMx numerical experiments. Special focus will be laid especially on the hypothesis that the pure presence of GWs can have a significant impact on transport and chemistry already in the troposphere. The model results will be validated with the existing observations and fresh results from the TEAMx observational campaign. New knowledge gained from previous stages will be transferred towards modifications of existing GW parameterization schemes and of the coupling of individual CCM modules to account for non-dissipative GW effects that will be finally tested in a well-established CCM.

Seznam odborné literatury

Alexander, M.J.: Gravity Waves in the Stratosphere. In The Stratosphere: Dynamics, Transport, and Chemistry (eds L.M. Polvani, A.H. Sobel and D.W. Waugh), 2010.
Bölöni, G., Kim, Y. H., Borchert, S., & Achatz, U.: Toward transient subgrid-scale gravity wave representation in atmospheric models. Part I: Propagation model including non-dissipative direct wave-mean-flow interactions. Journal of the Atmospheric Sciences, 2021.
Bühler, O.: Waves and mean flows, Cambridge University Press, 2014.
Cohen, N.Y. and Boos, W.R., The influence of orographic Rossby and gravity waves on rainfall. Q.J.R. Meteorol. Soc, 143: 845-851, https://doi.org/10.1002/qj.2969, 2017.
Fritts, David C., and M. Joan Alexander. "Gravity wave dynamics and effects in the middle atmosphere." Reviews of geophysics 41.1 (2003).
Podglajen, A., Plougonven, R., Hertzog, A., and Jensen, E.: Impact of gravity waves on the motion and distribution of atmospheric ice particles, Atmos. Chem. Phys., 18, 10799–10823, https://doi.org/10.5194/acp-18-10799-2018, 2018.
Roy, S., Sentchev, A., Schmitt, F.G. et al.: Impact of the Nocturnal Low-Level Jet and Orographic Waves on Turbulent Motions and Energy Fluxes in the Lower Atmospheric Boundary Layer. Boundary-Layer Meteorol. https://doi.org/10.1007/s10546-021-00629-x, 2021.
Serafin, S., Rotach, M. W., Arpagaus, M., Colfescu, I., Cuxart, J., De Wekker, S. F. J., Evans, M., Grubišič, V., Kalthoff, N., Karl, T., Kirshbaum, D. J., Lehner, M., Mobbs, S., Paci, A., Palazzi, E., Raudzens Bailey, A., Schmidli, J., Wohlfahrt, G., and Zardi, D.: Multi-scale transport and exchange processes in the atmosphere over mountains, Innsbruck university press, 1 edn., https://doi.org/10.15203/99106-003-1, https://uibk.ac.at/iup/buch_pdfs/10.1520399106-003-1.pdf, 2020.
Stenke, A., Schraner, M., Rozanov, E., Egorova, T., Luo, B., and Peter, T.: The SOCOL version 3.0 chemistry–climate model: description, evaluation, and implications from an advanced transport algorithm, Geosci. Model Dev., 6, 1407–1427, https://doi.org/10.5194/gmd-6-1407-2013, 2013.

Předběžná náplň práce v anglickém jazyce

Waves are commonly induced in the troposphere and propagate upward, hereby perturbing the background flow and transporting momentum and energy to the middle atmosphere. When the waves break, this momentum and energy is released, affecting stratospheric dynamics and temperatures. The spectrum of atmospheric waves spans from small-scale gravity waves (GWs) to large-scale planetary waves. The latter are induced by large scale mountain ridges and the heat contrast between ocean and land. Current climate models capture this type of waves as well as their vertical propagation and dissipation. GWs on the other hand originate from flow over small-scale orography, convection, frontal instabilities or spontaneous adjustment (see e.g. Fritts and Alexander, 2003; Alexander et al., 2010). As a phenomenon with small spatial scales and short time scales, at least a part of the GW spectrum cannot be resolved by climate or global weather prediction models and therefore have to be parameterised. The only parameterized effect of GWs is the dissipative deposition of momentum.
On the other side, several GW processes that are deduced from theory or numerical studies are not parameterized in models. For example, it is widely understood that GWs can influence atmospheric composition and transport directly via turbulent mixing during their breaking and via so-called non-dissipative effects connected with GW propagation and fluctuating trajectories inside the GWs (Bühler, 2014; Bölöni et al., 2021). This way GWs can modify for example cloudiness (Podglajen et al., 2018), boundary layer (Roy et al., 2021) and precipitation (Cohen and Boos, 2017). The deficiencies of the GW parameterizations in capturing the non-dissipative effects may prove as increasingly problematic, given that the accurate calculation of the advective transport of chemical species is of fundamental importance for the overall performance of chemistry-climate models (Stenke et al., 2013). Given the recent increases of availability of GW resolving simulations, the candidate will be in an ideal position to define a new research field by studying and diagnosing the non-dissipative GW effects in GW-resolving datasets and transforming this knowledge towards improvements of state-of-the-science climate models. The goals of the thesis are well connected with the efforts of the international research community and will guarantee an active participation of the applicant within the Multi-scale Transport and Exchange Processes in the Atmosphere over Mountains Programme and experiment (TEAMx; Serafin et al., 2020) that will conduct a major observational campaign in 2025.