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

single smoothing operation. Fig . 1. Domain configuration for WRF simulation of 28 Jul 2014. The boundary of the map represents the outermost domain. The inner domains are denoted as “d02” and “d03.” Initial and lateral boundary conditions were obtained from the National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) model analyses. The simulation was initialized at 0000 UTC 27 July 2014 and run for 48 h to 0000 UTC 29 July 2014 with lateral boundary conditions updated

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Ronald B. Smith and Christopher G. Kruse

conditions from MERRA, version 2 (MERRA-2), global simulations. This run was compared carefully with a prior run using the operational ECMWF analysis as boundary conditions ( Kruse et al. 2016 ). The two runs compared very well. A detailed comparison with observations was carried out, including aircraft leg winds and temperatures and vertically smoothed balloon soundings. The agreement was excellent. The general meteorological conditions during this period are described by Gisinger et al. (2017) . From

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

conditions. d. Global meteorological data Operational analyses of the ECMWF IFS are used to provide meteorological data to characterize the atmospheric situation and to serve as initial and boundary data for the mesoscale numerical simulations. The analysis fields of the IFS cycle 40r1 have a horizontal resolution of about 16 km (T1279) and 137 vertical model levels (L137). The model top of the T1279/L137 IFS was located at 0.01 hPa. e. Mesoscale numerical simulations To derive gravity wave parameters in

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

used for the short- and longwave radiation processes ( Fu et al. 1997 ). The initial fields for the model are created from a three-dimensional variational data assimilation (i.e., 3DVAR) method ( Daley and Barker 2001 ). Lateral boundary conditions for the outermost grid mesh are derived from Navy Global Environmental Model (NAVGEM) forecast fields ( Hogan et al. 2014 ). The computational domain contains two horizontally nested grid meshes of 256 × 150 and 433 × 358 grid points, and the

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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

numerical simulation and NCEP GFS = National Centers for Environmental Prediction Global Forecast System. MOTIVATIONS. GWs, or buoyancy waves, for which the restoring force is due to negatively (positively) buoyant air for upward (downward) displacements, play major roles in atmospheric dynamics, spanning a wide range of spatial and temporal scales. Vertical and horizontal wavelengths, λ z and λ h , respectively, for vertically propagating GWs are dictated by their sources and propagation conditions

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Benjamin Witschas, Stephan Rahm, Andreas Dörnbrack, Johannes Wagner, and Markus Rapp

GWs, turbulence, and GW breaking at the tropopause region by means of in situ data acquired on different flight levels. Compared to such kinds of in situ measurements, horizontal and vertical winds can be measured by lidar at several altitudes simultaneously. Bluman and Hart (1988) used airborne Doppler wind measurements (from 3 km to the ground) to validate linear lee-wave model calculations, Weissmann et al. (2005a) investigated the vertical transport from the boundary layer into the free

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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

restriction is typically overcome through the use of analysis or reanalysis products, which provide an estimate of the state of the atmosphere based on assimilation of available heterogeneous observations using data assimilation systems (DASs). However, as depicted in Fig. 1b , the suite of NWP DASs used during DEEPWAVE all had upper boundaries that did not extend into the MLT. Indeed, at present, no NWP center provides either near-real-time or retrospective analysis products above 60–80-km altitude

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

topography and initial/boundary conditions. These simulations are extensively validated against research aircraft, radiosonde, and satellite observations collected over New Zealand during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) field campaign during May–July 2014 ( Fritts et al. 2016 ). From these simulations, the vertical fluxes of horizontal momentum and GWD are quantified and compared with DEEPWAVE observations and parameterized quantities within NASA’s Modern-Era Retrospective

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Stephen D. Eckermann, Dave Broutman, Jun Ma, James D. Doyle, Pierre-Dominique Pautet, Michael J. Taylor, Katrina Bossert, Bifford P. Williams, David C. Fritts, and Ronald B. Smith

across Auckland Island were close to parallel to the forecast upstream surface flow. Fig . 3. Three-dimensional depiction of part of the NGV flight track during RF23, with colors along track depicting time (UTC hours; color bar at top left). Flight track from ~0724 to 0933 UTC to/from Macquarie Island lies outside the plot boundary to the southwest. Blue curve on ocean surface shows NGV ground track (as in Fig. 2b ), showing repeated transects across Auckland Island, spotlighted in white. Terrain

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