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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

indices. The Southern Oscillation index (SOI) is the difference in mean sea level pressure (MSLP) between the western and eastern tropical Pacific. In the austral winter months of June–August (JJA), negative SOI values are associated with anomalous southwesterly flow over New Zealand ( Gordon 1986 ) and a higher mean seasonal frequency of blockings ( Kidson 2000 ). In 2014, the monthly mean SOI taken from NCEP–NCAR reanalyses ( http://www.cpc.ncep.noaa.gov/data/indices/soi ) switched from positive

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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

, such as those that often accompany large radar and/or rocket facilities, have made especially valuable contributions to GW studies. This is because no single instrument can define all of the atmospheric properties and spatial and temporal variability needed to fully quantify the local GW field. Examples of these facilities include the Arctic Lidar Observatory for Middle Atmosphere Research in Norway (69.3°N); the Poker Flat Research Range in Alaska (65.1°N); the Bear Lake Observatory in Utah (42°N

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Christopher G. Kruse and Ronald B. Smith

1. Introduction Gravity waves are atmospheric buoyancy oscillations that transport energy and horizontal momentum vertically throughout the atmosphere ( McLandress 1998 ). The vertical propagation and dissipation of gravity waves are important as the carried energy and momentum are deposited wherever these waves break, affecting the mean flow. Gravity waves and their dissipation have long been recognized to be important in middle atmosphere dynamics ( Fritts 1989 ). Important gravity wave

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Ronald B. Smith, Alison D. Nugent, Christopher G. Kruse, David C. Fritts, James D. Doyle, Steven D. Eckermann, Michael J. Taylor, Andreas Dörnbrack, M. Uddstrom, William Cooper, Pavel Romashkin, Jorgen Jensen, and Stuart Beaton

” sensors are given in Table 1 . Table 1. Primary sensor uncertainties on the GV. From these values, we can estimate the errors that enter the flux calculation. As mean values are removed before flux computation, the flux errors arise only from the random errors. To propagate the errors for momentum flux we imagine a transect with anticorrelated sinusoidal u ′ and w ′ oscillations with amplitudes of 5 and 1 m s −1 , respectively. With air density of 0.3 kg m −3 , we define a reference value MF x

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

lidar for every output time. The horizontally interpolated vertical temperature profiles were then interpolated to the same vertical grid as specified by the Esrange lidar observations and averaged over the same time spans. The WRF vertical temperature profiles are relatively smooth compared to the lidar data because of the numerical scheme minimizing spurious oscillations at grid scale. Thus, no additional smoothing was applied. Finally, temperature perturbations were determined applying the same

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

STW oscillations are again seen in aircraft lidar temperatures ( Fig. 5e ) and in AIRS brightness temperatures ( Fig. 5f ), whereas wave signals are noticeably weaker in the flight-level temperatures in Fig. 5g . Fig . 5. (a) Ground track of GV HIAPER RF07 (gray curves) on 19 Jun 2014, with flight legs 3, 5, 6, and 7 marked in red, blue, orange, and cyan, respectively. (right) Perturbations as a function of flight distance along the separate flight legs from the reference points marked by stars

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