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Mozhgan Amiramjadi, Ali R. Mohebalhojeh, Mohammad Mirzaei, Christoph Zülicke, and Riwal Plougonven

European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS), for nonorographic gravity waves, the amplitude at source level is set to a globally uniform value and adjusted by a prescribed relation for latitude and resolution (see section 5.3 in ECMWF 2018 ). This is a gross simplification of spatial variability and the complete neglect of temporal variability in the wave emission process. Following earlier work by Zülicke and Peters (2008) , a new approach to

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

reactions ( Teitelbaum and Sadourny 1998 ; Carslaw et al. 1998 ). Simulation of mesoscale mountain waves especially posed a challenge, and special methods such as linear wave prediction models and mesoscale forecast models were used in the past to predict their local formation (e.g., Dörnbrack et al. 1998 ; Eckermann et al. 2006 ). In this day and age, global operational NWP models use spatial resolutions, which hardly could be attained by limited-area models several years ago. For example, the

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Martina Bramberger, Andreas Dörnbrack, Henrike Wilms, Steffen Gemsa, Kevin Raynor, and Robert Sharman

-term forecast and the spaceborne observations of polar stratospheric clouds indicates a fundamental trend: the finer resolution and increasing realism of operational NWP model outputs offers a valuable quantitative source for mesoscale flow components that were heretofore not accessible globally ( Bauer et al. 2015 ). The importance of mountain waves, not only to aviation safety but for the general atmospheric circulation from the boundary layer to the middle atmosphere (e.g., through the transport and

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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

. Data sources Operational analyses of the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) are used to provide meteorological data to characterize the atmospheric situation. The 6-hourly operational analysis and hourly forecast fields of the IFS cycle 40r1 have a horizontal resolution on the reduced linear Gaussian grid of about 16 km (T L 1279) and 137 vertical model levels (L137) from the ground to ~80 km (0.01 hPa) with layer thicknesses gradually

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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

shown in Fig. 1 (bottom). Figure 2 shows the extent of all DEEPWAVE measurements in altitude and latitude. F ig . 2. North–south cross section showing the types of airborne and ground-based instruments contributing to DEEPWAVE measurements and their coverage in latitude and altitude. DEEPWAVE began with a test flight-planning exercise from 1 to 10 August 2013 to gain experience with forecasting and flight planning and to assess the reliability of such forecasts in preparation for the real field

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

altitude range, the lidar observations are complemented with temperatures simulated numerically by the Advanced Research version of the Weather Research and Forecasting (WRF) Model (ARW; Skamarock and Klemp 2008 ). Our goal is to determine the wave characteristics from the lower troposphere to the mesosphere. For this purpose, we combine and analyze the lidar temperature measurements and the validated mesoscale simulation results. Prerequisites of this approach are high-resolution numerical

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

levels, and a model top at 0.01 hPa, with numerical damping starting at 10 hPa ( Jablonowski and Williamson 2011 ). Moreover, mesoscale numerical simulations with the Weather Research and Forecasting (WRF; 1 Skamarock et al. 2008 ; Skamarock and Klemp 2008 ) Model are performed. With the use of Advanced Research WRF version 3.7, atmospheric simulations are generated processing operational ECMWF analyses as initial and boundary conditions. Two nested model domains are centered at 43°S, 169°E over

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Claudia Christine Stephan, Cornelia Strube, Daniel Klocke, Manfred Ern, Lars Hoffmann, Peter Preusse, and Hauke Schmidt

produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), and integrated forward for 40 days until 0000 UTC 10 September 2016. The simulations were forced at the lower boundary with daily sea surface temperatures also taken from the analysis of ECMWF. ICON and NICAM do not use any type of GW drag parameterizations. The physics parameterizations in IFS are those of the operational setup and include nonorographic ( Scinocca 2003 ) and orographic ( Lott and Miller 1997 ) GW drag

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Jannik Wilhelm, T. R. Akylas, Gergely Bölöni, Junhong Wei, Bruno Ribstein, Rupert Klein, and Ulrich Achatz

to be usable for nonrotating cases as well. The Boussinesq setting of our analysis does not say that non-Boussinesq effects are irrelevant. The vertical decrease of ambient density would play an important role in operational weather forecast and climate models. This is left out here for the mere sake of simplicity, but corresponding generalizations as in Bölöni et al. (2016) seem straightforward. Moreover, in an analysis based on fully compressible dynamics, Achatz et al. (2017) identify

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Junhong Wei, Gergely Bölöni, and Ulrich Achatz

; Butchart 2014 ). The dynamics of the middle atmosphere can influence the tropospheric circulation by downward control ( Haynes et al. 1991 ), and it can be very important for the forecasting of weather ( Baldwin and Dunkerton 2001 ) and climate ( Scaife et al. 2005 , 2012 ). Despite the increasing computational power, an important range of GW spatial scales remains unresolved in most atmospheric global circulation models (GCM) or in global numerical weather prediction (NWP) models ( Alexander et al

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