Infrasound scattering from stochastic gravity wave packets

2017 ◽  
Vol 141 (5) ◽  
pp. 3628-3628
Author(s):  
Christophe MILLET ◽  
Bruno RIBSTEIN ◽  
Francois LOTT
Keyword(s):  
Gravity Wave ◽  
Wave Packets ◽  
Stochastic Gravity

scholarly journals The nonlinear effects on the characteristics of gravity wave packets: dispersion and polarization relations

2000 ◽  
Vol 18 (10) ◽  
pp. 1316-1324 ◽  
Author(s):  
S.-D. Zhang ◽  
F. Yi ◽  
J.-F. Wang
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Middle Atmosphere ◽  
Wave Packets ◽  
Nonlinear Effects ◽  
Wave Theory ◽  
Nonlinear Propagation ◽  
Waves And Tides ◽  
Time Variations ◽  
Isothermal Atmosphere

Abstract. By analyzing the results of the numerical simulations of nonlinear propagation of three Gaussian gravity-wave packets in isothermal atmosphere individually, the nonlinear effects on the characteristics of gravity waves are studied quantitatively. The analyses show that during the nonlinear propagation of gravity wave packets the mean flows are accelerated and the vertical wavelengths show clear reduction due to nonlinearity. On the other hand, though nonlinear effects exist, the time variations of the frequencies of gravity wave packets are close to those derived from the dispersion relation and the amplitude and phase relations of wave-associated disturbance components are consistent with the predictions of the polarization relation of gravity waves. This indicates that the dispersion and polarization relations based on the linear gravity wave theory can be applied extensively in the nonlinear region.Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

scholarly journals Multi-instrument gravity-wave measurements over Tierra del Fuego and the Drake Passage – Part 1: Potential energies and vertical wavelengths from AIRS, COSMIC, HIRDLS, MLS-Aura, SAAMER, SABER and radiosondes

2016 ◽  
Vol 9 (3) ◽  
pp. 877-908 ◽  
Author(s):  
Corwin J. Wright ◽  
Neil P. Hindley ◽  
Andrew C. Moss ◽  
Nicholas J. Mitchell
Keyword(s):  
Gravity Wave ◽  
Wave Packets ◽  
Lower Thermosphere ◽  
Lower Troposphere ◽  
Drake Passage ◽  
Tierra Del Fuego ◽  
Data Sets ◽  
Meteor Radar ◽  
Diverse Range ◽  
Wide Range

Abstract. Gravity waves in the terrestrial atmosphere are a vital geophysical process, acting to transport energy and momentum on a wide range of scales and to couple the various atmospheric layers. Despite the importance of these waves, the many studies to date have often exhibited very dissimilar results, and it remains unclear whether these differences are primarily instrumental or methodological. Here, we address this problem by comparing observations made by a diverse range of the most widely used gravity-wave-resolving instruments in a common geographic region around the southern Andes and Drake Passage, an area known to exhibit strong wave activity. Specifically, we use data from three limb-sounding radiometers (Microwave Limb Sounder, MLS-Aura; HIgh Resolution Dynamics Limb Sounder, HIRDLS; Sounding of the Atmosphere using Broadband Emission Radiometry, SABER), the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) GPS-RO constellation, a ground-based meteor radar, the Advanced Infrared Sounder (AIRS) infrared nadir sounder and radiosondes to examine the gravity wave potential energy (GWPE) and vertical wavelengths (λz) of individual gravity-wave packets from the lower troposphere to the edge of the lower thermosphere ( ∼  100 km). Our results show important similarities and differences. Limb sounder measurements show high intercorrelation, typically  > 0.80 between any instrument pair. Meteor radar observations agree in form with the limb sounders, despite vast technical differences. AIRS and radiosonde observations tend to be uncorrelated or anticorrelated with the other data sets, suggesting very different behaviour of the wave field in the different spectral regimes accessed by each instrument. Evidence of wave dissipation is seen, and varies strongly with season. Observed GWPE for individual wave packets exhibits a log-normal distribution, with short-timescale intermittency dominating over a well-repeated monthly-median seasonal cycle. GWPE and λz exhibit strong correlations with the stratospheric winds, but not with local surface winds. Our results provide guidance for interpretation and intercomparison of such data sets in their full context.

scholarly journals Simulation of Inertia–Gravity Waves in a Poleward-Breaking Rossby Wave

2006 ◽  
Vol 63 (12) ◽  
pp. 3253-3276 ◽  
Author(s):  
Christoph Zülicke ◽  
Dieter Peters
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Rossby Wave ◽  
Rossby Waves ◽  
Mesoscale Model ◽  
Wave Packets ◽  
The Impact ◽  
Jet Streak ◽  
Horizontal Wavelength ◽  
Inertia Gravity Waves

Poleward-breaking Rossby waves often induce an upper-level jet streak over northern Europe. Dominant inertia–gravity wave packets are observed downstream of this jet. The physical processes of their generation and propagation, in such a configuration, are investigated with a mesoscale model. The study is focused on an observational campaign from 17 to 19 December 1999 over northern Germany. Different simulations with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) have been performed. For a high-resolution process study, three domains were set up that encompass the evolution of Rossby waves and that of inertia–gravity waves. To minimize the impact of model damping, the horizontal and vertical resolution has been adjusted appropriately. With a novel statistical approach, the properties of inertia–gravity wave packets have been estimated. This method uses the horizontal divergence field and takes into account the spatial extension of a wave packet. It avoids the explicit treatment of the background field and works for arbitrary wavelength. Two classes of inertia–gravity waves were found: subsynoptic waves with a horizontal wavelength of about 500 km and mesoscale waves with a horizontal wavelength of about 200 km. The subsynoptic structures were also detected in radiosonde observations during this campaign. The similarity between simulated and observed wavelengths and amplitudes suggests that the simulations can be considered as near realistic. Spontaneous radiation from unbalanced flow is an important process of inertia–gravity wave generation. Synoptic-scale imbalances in the exit region of the upper-tropospheric jet streak were identified with the smoothed cross-stream Lagrangian Rossby number. In a number of simulations with different physics, it was found that the inertia–gravity wave activity was related to the tropospheric jet, orography, and moist convection. The upward propagation of inertia–gravity waves was favored during this event of a poleward-breaking Rossby wave. The presence of the polar vortex induced background winds exceeding the critical line. Consequently, the activity of inertia–gravity waves in the lower stratosphere increased by an order of magnitude during the case study. The successful simulation of the complex processes of generation and propagation showed the important role of poleward Rossby wave breaking for the appearance of inertia–gravity waves in the midlatitudes.

scholarly journals Estimation of Gravity Wave Momentum Flux and Phase Speeds from Quasi-Lagrangian Stratospheric Balloon Flights. Part I: Theory and Simulations

2008 ◽  
Vol 65 (10) ◽  
pp. 3042-3055 ◽  
Author(s):  
Gillian Boccara ◽  
Albert Hertzog ◽  
Robert A. Vincent ◽  
François Vial
Keyword(s):  
Gravity Wave ◽  
Wave Packets ◽  
Phase Speed ◽  
Companion Paper ◽  
Time Frequency ◽  
Long Duration ◽  
Short Period ◽  
Momentum Fluxes ◽  
Stratospheric Balloon ◽  
Wave Momentum

A methodology for estimating gravity wave characteristics from quasi-Lagrangian observations provided by long-duration, superpressure balloon flights in the stratosphere is reviewed. Wavelet analysis techniques are used to detect gravity wave packets in observations of pressure, temperature, and horizontal velocity. An emphasis is put on the estimation of gravity wave momentum fluxes and intrinsic phase speeds, which are generally poorly known on global scales in the atmosphere. The methodology is validated using Monte Carlo simulations of time series that mimic the balloon measurements, including the uncertainties associated with each of the meteorological parameters. While the azimuths of the wave propagation direction are accurately retrieved, the momentum fluxes are generally slightly underestimated, especially when wave packets overlap in the time–frequency domain, or for short-period waves. A proxy is derived to estimate by how much momentum fluxes are reduced by the analysis. Retrievals of intrinsic phase speeds are less accurate, especially for low phase speed waves. A companion paper (Part II) implements the methodology to observations gathered during the Vorcore campaign that took place in Antarctica between September 2005 and February 2006.

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