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Markus Rapp, Bernd Kaifler, Andreas Dörnbrack, Sonja Gisinger, Tyler Mixa, Robert Reichert, Natalie Kaifler, Stefanie Knobloch, Ramona Eckert, Norman Wildmann, Andreas Giez, Lukas Krasauskas, Peter Preusse, Markus Geldenhuys, Martin Riese, Wolfgang Woiwode, Felix Friedl-Vallon, Björn-Martin Sinnhuber, Alejandro de la Torre, Peter Alexander, Jose Luis Hormaechea, Diego Janches, Markus Garhammer, Jorge L. Chau, J. Federico Conte, Peter Hoor, and Andreas Engel

band of almost zonally symmetric GW activity and related momentum fluxes will be referred to as the “gravity wave belt.” F ig . 1. Illustration of the GW belt based on ERA5 temperature perturbations for (left) August and (right) September 2019 at a pressure levels of 10 hPa. Shown is | T′ | = ⁡ ( T 639 − T 106 ) 2 – (K; see “Models” section for details). The red oval marks the target area where airborne measurements were conducted during SOUTHTRAC-GW. While observational evidence for the GW belt

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Gergely Bölöni, Bruno Ribstein, Jewgenija Muraschko, Christine Sgoff, Junhong Wei, and Ulrich Achatz

again statically stable. Following Lindzen (1981) and Becker (2004) , the turbulent fluxes are modeled by eddy viscosity and diffusivity so that small scales are damped more strongly than larger scales. The buoyancy equation, for example, is supplemented by a diffusion term with the turbulent eddy diffusivity coefficient . By Fourier transformation in space and integration over a short time interval , one obtains the following as change of the buoyancy amplitude: Employing identical eddy

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Tyler Mixa, Andreas Dörnbrack, and Markus Rapp

from the Advanced Mesospheric Temperature Mapper (AMTM), which remained stationary for several hours ( Pautet et al. 2016 ). Simultaneous lidar measurements of sodium mixing ratios in the mesosphere and lower thermosphere (MLT) indicate peak gravity wave amplitudes of ≈±10 K at z ≈ 83 km and λ x ≈ 40 km. Later flight legs show strong indications of gravity wave breaking, with apparent vortex ring formation and momentum fluxes estimated over 320 m 2 s −2 ( Pautet et al. 2016 ). Eckermann et al

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Benedikt Ehard, Peggy Achtert, Andreas Dörnbrack, Sonja Gisinger, Jörg Gumbel, Mikhail Khaplanov, Markus Rapp, and Johannes Wagner

of the combined dataset derives vertical wavelength and gravity wave potential energy density using the observed and simulated temperature deviations from the estimated background profiles. Additionally, the WRF Model output provides quantities like wind, vertical energy fluxes, and stability parameters (Richardson number and displacement of isentropic surfaces) in the troposphere and lower stratosphere. Thus, results of the combined dataset enable a more comprehensive characterization of gravity

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Mark Schlutow

vector form: (12) ∂ y ∂ t + ∂ F ⁡ ( y ) ∂ z = G ⁡ ( y ) , with a flux F and an inhomogeneity G where y = ( k z , a , u ) T is the prognostic vector. 4. General stationary solutions of the modulation equations In this section we will explore general stationary solutions before we focus on particular solutions for which we will present stability analysis in the upcoming sections. In the inviscid limit (i.e., Λ → 0), the modulation equations assume stationary solutions where ∂ p /∂ x = 0

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Mahnoosh Haghighatnasab, Mohammad Mirzaei, Ali R. Mohebalhojeh, Christoph Zülicke, and Riwal Plougonven

forcing mechanism. The spectrum of IGWs generated by convection depends on the latent heat released, properties of convection in the lower troposphere and the environmental wind ( Beres and Alexander 2004 ; Beres et al. 2005 ). There have been many studies devoted to finding a suitable method for parameterization of convectively generated IGWs in the GCMs mainly following two main approaches, based on either the momentum flux (e.g., Song et al. 2003 ; Beres and Alexander 2004 ) or the energy (e

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Christoph Zülicke, Erich Becker, Vivien Matthias, Dieter H. W. Peters, Hauke Schmidt, Han-Li Liu, Laura de la Torre Ramos, and Daniel M. Mitchell

circulation by GWs is considered in order to derive a relation between temperature anomalies and the GW phase speed. According to Holton (1982) the zonal-mean residual circulation is driven by the zonal GW pseudomomentum flux (GWF) divergence The induced residual meridional circulation enforces a certain vertical motion through the continuity equation From the thermodynamic equation, which is modeled as a radiative relaxation to an equilibrium temperature T e , the dynamically forced temperature is

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Andreas Dörnbrack, Sonja Gisinger, Michael C. Pitts, Lamont R. Poole, and Marion Maturilli

. Keckhut , 2015 : Seasonal variation of gravity wave activity at midlatitudes from 7 years of COSMIC GPS and Rayleigh lidar temperature observations . Geophys. Res. Lett. , 42 , 1251 – 1258 , doi: 10.1002/2014GL062891 . 10.1002/2014GL062891 Malardel , S. , and N. P. Wedi , 2016 : How does subgrid-scale parametrization influence nonlinear spectral energy fluxes in global NWP models? J. Geophys. Res. Atmos. , 121 , 5395 – 5410 , doi: 10.1002/2015JD023970 . 10.1002/2015JD023970 Manney , G

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