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Sonja Gisinger, Andreas Dörnbrack, Vivien Matthias, James D. Doyle, Stephen D. Eckermann, Benedikt Ehard, Lars Hoffmann, Bernd Kaifler, Christopher G. Kruse, and Markus Rapp

information about the various datasets used in this study. In section 3 , we discuss specific tropospheric flow regimes and forcing conditions during DEEPWAVE. Section 4 is devoted to the tropopause layer. The stratospheric and mesospheric wind and thermal conditions providing the ambient atmospheric profiles for deep propagating gravity waves are described in section 5 . There, planetary wave activity and its impact on the location of the PNJ and the polar vortex are discussed. Special attention is

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Christopher G. Kruse, Ronald B. Smith, and Stephen D. Eckermann

playing a more secondary role in the extratropical stratosphere. The focus of this study is the propagation and attenuation of gravity waves within the extratropical stratosphere. In the stratosphere, the important equator-to-pole Brewer–Dobson circulation is driven by momentum deposited in the extratropics by both planetary-scale Rossby waves and GWs (e.g., Holton et al. 1995 ). Within chemistry–climate models, planetary waves are resolved while the smaller-scale GWs and their GWD are largely

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Stephen D. Eckermann, Jun Ma, Karl W. Hoppel, David D. Kuhl, Douglas R. Allen, James A. Doyle, Kevin C. Viner, Benjamin C. Ruston, Nancy L. Baker, Steven D. Swadley, Timothy R. Whitcomb, Carolyn A. Reynolds, Liang Xu, N. Kaifler, B. Kaifler, Iain M. Reid, Damian J. Murphy, and Peter T. Love

system and the MLT observations it assimilates are described in section 2 . Reanalysis experiments for the 2014 austral winter are outlined in section 3 . Reanalyzed temperatures and winds in the MLT are validated against independent observations in section 4 . The 0–100-km reanalysis products are applied in section 5 to delineate aspects of planetary-wave dynamics specific to the greater New Zealand region that potentially impacted MLT gravity waves observed during DEEPWAVE. Major scientific

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Stephen D. Eckermann, James D. Doyle, P. Alex Reinecke, Carolyn A. Reynolds, Ronald B. Smith, David C. Fritts, and Andreas Dörnbrack

. Semicontinuous breaking of gravity waves around the globe sustains planetary-scale forces that drive large-scale circulations and climate. Wave breaking is also the dominant source of turbulence and vertical mixing throughout the stratosphere, mesosphere and lower thermosphere. In these and other ways, gravity waves affect weather and climate at all altitudes and across scales ( Fritts and Alexander 2003 ). Gravity waves exist over a broad range of horizontal wavelengths ( λ h ~ 5–1000 km), while breaking

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Johnathan J. Metz, Dale R. Durran, and Peter N. Blossey

1. Introduction Gravity wave activity with maximum amplitude in the stratosphere downstream of major mountain ranges has previously been explained as a result of wave breaking inducing secondary wave generation ( Bacmeister and Schoeberl 1989 ; Vadas et al. 2003 ), the trapping or partial trapping of gravity waves in a duct of high static stability in the tropopause inversion layer ( Smith et al. 2016 ; Fritts et al. 2018 ) or the vertical propagation of waves through this layer from below

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Qingfang Jiang, James D. Doyle, Stephen D. Eckermann, and Bifford P. Williams

. Geleyn , 1982 : A short history of the operational PBL parameterization at ECMWF. Proc. Workshop on Planetary Boundary Layer Parameterization , Reading, United Kingdom, ECMWF, 59 – 79 . McLandress , C. , T. G. Shepherd , S. Polavarapu , and S. R. Beagley , 2012 : Is missing orographic gravity wave drag near 60°S the cause of the stratospheric zonal wind biases in chemistry–climate models? J. Atmos. Sci. , 69 , 802 – 818 , . 10.1175/JAS-D-11

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

), which turn out to be periods when mountain waves were excited by the flow across the Scandinavian mountain ridge. These perturbations are correlated with an enhanced tropospheric wind and a jet stream near the tropopause ( Fig. 2b ). Most noticeable are the downward-propagating wind anomalies in the period 3–4 December 2013. The upper-stratospheric and mesospheric winds show a remarkable variability, which probably results from planetary waves disturbing the polar vortex during this period. Fig . 2

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Tanja C. Portele, Andreas Dörnbrack, Johannes S. Wagner, Sonja Gisinger, Benedikt Ehard, Pierre-Dominique Pautet, and Markus Rapp

linear mountain-wave theory ( Smith 1979 ). Moreover, there are numerous numerical studies about transiently forced mountain waves. Lott and Teitelbaum (1993a , b ) investigated the wave dynamics in a 2D linear time-dependent model with transient incident stably stratified flow. Chen et al. (2005 , 2007 ) and Hills and Durran (2012) extended the work of Lott and Teitelbaum (1993a , b ) and studied the impact of the flow of a time-dependent barotropic planetary square wave in a uniformly

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David C. Fritts, Ronald B. Smith, Michael J. Taylor, James D. Doyle, Stephen D. Eckermann, Andreas Dörnbrack, Markus Rapp, Bifford P. Williams, P.-Dominique Pautet, Katrina Bossert, Neal R. Criddle, Carolyn A. Reynolds, P. Alex Reinecke, Michael Uddstrom, Michael J. Revell, Richard Turner, Bernd Kaifler, Johannes S. Wagner, Tyler Mixa, Christopher G. Kruse, Alison D. Nugent, Campbell D. Watson, Sonja Gisinger, Steven M. Smith, Ruth S. Lieberman, Brian Laughman, James J. Moore, William O. Brown, Julie A. Haggerty, Alison Rockwell, Gregory J. Stossmeister, Steven F. Williams, Gonzalo Hernandez, Damian J. Murphy, Andrew R. Klekociuk, Iain M. Reid, and Jun Ma

, temperatures, and turbulence from ∼30 to 100 km and enabled studies of energy dissipation rates due to GW breaking, MW filtering during a stratospheric warming, and anomalous MLT mean structure accompanying strong planetary waves (PWs) in the Southern Hemisphere and other dynamics (e.g., Rapp et al. 2004 ; Wang et al. 2006 ; Goldberg et al. 2006 ). Multiple types of radars have quantified GW amplitudes, scales, spectral character, momentum fluxes, and evidence of various interaction and instability

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Christopher G. Kruse and Ronald B. Smith

1. Introduction It is well known that gravity waves (GWs) flux horizontal momentum vertically in Earth’s atmosphere, depositing momentum wherever they attenuate (e.g., Bretherton 1969 ; McLandress 1998 ; Alexander et al. 2010 ). Mountain waves (MWs), GWs generated by flow over mountains, attain this momentum flux (MF) through a pressure drag interaction with the mountains that generate them ( Miles 1969 ; Smith 1979 ). That is, as the atmosphere flows over mountains, a pressure drag is

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