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Articles 1 - 15 of 15
Full-Text Articles in Physical Sciences and Mathematics
Observation And Modeling Of Gravity Wave Propagation Through Reflection And Critical Layers Above Andes Lidar Observatory At Cerro Pachón, Chile, Bing Cao, Christopher J. Heale, Yafang Guo, Alan Z. Liu, Jonathan B. Snively
Observation And Modeling Of Gravity Wave Propagation Through Reflection And Critical Layers Above Andes Lidar Observatory At Cerro Pachón, Chile, Bing Cao, Christopher J. Heale, Yafang Guo, Alan Z. Liu, Jonathan B. Snively
Jonathan B. Snively
A complex gravity wave event was observed from 04:30 to 08:10 UTC on 16 January 2015 by a narrow-band sodium lidar and an all-sky airglow imager located at Andes Lidar Observatory (ALO) in Cerro Pachón (30.25∘S, 70.73∘W), Chile. The gravity wave packet had a period of 18–35 min and a horizontal wavelength of about 40–50 km. Strong enhancements of the vertical wind perturbation, exceeding10 m s−1, were found at ∼90 km and ∼103 km, consistent with nearly evanescent wave behavior near a reflection layer. A reduction in vertical wavelength was found as the phase speed approached the background wind speed …
Numerical Modeling Of A Multiscale Gravity Wave Event And Its Airglow Signatures Over Mount Cook, New Zealand, During The Deepwave Campaign, C. J. Heale, K. Bossert, J. B. Snively, D. C. Fritts, P. -D. Pautet, M. J. Taylor
Numerical Modeling Of A Multiscale Gravity Wave Event And Its Airglow Signatures Over Mount Cook, New Zealand, During The Deepwave Campaign, C. J. Heale, K. Bossert, J. B. Snively, D. C. Fritts, P. -D. Pautet, M. J. Taylor
Jonathan B. Snively
A 2-D nonlinear compressible model is used to simulate a large-amplitude, multiscale mountain wave event over Mount Cook, NZ, observed as part of the Deep Propagating Gravity Wave Experiment (DEEPWAVE) campaign and to investigate its observable signatures in the hydroxyl (OH) layer. The campaign observed the presence of a �x = 200 km mountain wave as part of the 22nd research flight with amplitudes of >20 K in the upper stratosphere that decayed rapidly at airglow heights. Advanced Mesospheric Temperature Mapper (AMTM) showed the presence of small-scale (25–28 km) waves within the warm phase of the large mountain wave. The …
Gravity Wave Ducting In The Upper Mesosphere And Lower Thermosphere Duct System, R. L. Walterscheid, Michael P. Hickey Ph.D.
Gravity Wave Ducting In The Upper Mesosphere And Lower Thermosphere Duct System, R. L. Walterscheid, Michael P. Hickey Ph.D.
Michael P. Hickey
We report on a numerical study of gravity wave propagation in a pair of ducts located in a region where dramatic changes in the airglow most likely associated with ducted wave trains are observed. We examine ducting in an upper mesosphere inversion (INV) and an always present lower thermosphere stable layer (LTD) for a range of phase speeds and horizontal wavelengths characteristic of ducting events. We analyze the propagation and modal structure of ducted waves for backgrounds with increasing realism, starting with a climatological temperature profile where only the LTD is present. In succession, we add the INV based on …
Numerical And Statistical Evidence For Long-Range Ducted Gravity Wave Propagation Over Halley, Antarctica, J. B. Snively, K. Nielsen, M. P. Hickey, C. J. Heale, M. J. Taylor, T. Moffat-Griffin
Numerical And Statistical Evidence For Long-Range Ducted Gravity Wave Propagation Over Halley, Antarctica, J. B. Snively, K. Nielsen, M. P. Hickey, C. J. Heale, M. J. Taylor, T. Moffat-Griffin
Michael P. Hickey
Abundant short-period, small-scale gravity waves have been identified in the mesosphere and lower thermosphere over Halley, Antarctica, via ground-based airglow image data. Although many are observed as freely propagating at the heights of the airglow layers, new results under modeled conditions reveal that a significant fraction of these waves may be subject to reflections at altitudes above and below.The waves may at times be trapped within broad thermal ducts, spanning from the tropopause or stratopause to the base of the thermosphere (~140 km), which may facilitate long-range propagation (~1000s of km) under favorable wind conditions.
Atmospheric Airglow Fluctuations Due To A Tsunami‐Driven Gravity Wave Disturbance, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid
Atmospheric Airglow Fluctuations Due To A Tsunami‐Driven Gravity Wave Disturbance, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid
Michael P. Hickey
A spectral full‐wave model is used to study the upward propagation of a gravity wave disturbance and its effect on atmospheric nightglow emissions. Gravity waves are generated by a surface displacement that mimics a tsunami having a maximum amplitude of 0.5 m, a characteristic horizontal wavelength of 400 km, and a horizontal phase speed of 200 m/s. The gravity wave disturbance can reach F region altitudes before significant viscous dissipation occurs. The response of the OH Meinel nightglow in the mesopause region (∼87 km altitude) produces relative brightness fluctuations, which are ∼1% of the mean for overhead viewing. The wave …
Numerical Simulation Of The Long-Range Propagation Of Gravity Wave Packets At High Latitudes, C. J. Heale, J. B. Snively, M. P. Hickey
Numerical Simulation Of The Long-Range Propagation Of Gravity Wave Packets At High Latitudes, C. J. Heale, J. B. Snively, M. P. Hickey
Michael P. Hickey
We use a 2-D, nonlinear, time-dependent numerical model to simulate the propagation of wave packets under average high latitude, winter conditions. We investigate the ability of waves to propagate large horizontal distances, depending on their direction of propagation relative to the average modeled ambient winds. Wave sources were specified to represent the following: (1) the most common wave parameters inferred from observations of Nielsen et al. (2009) ((18 km λᵪ , 7.5 min period), (2) waves consistent with the average phase speed observed (40 m/s) but outlying horizontal wavelength and period values (40 km λᵪ , 17 min period), and …
A Simulation Study Of Space-Based Observations Of Gravity Waves In The Airglow Using Observed Aloha-93 Wave Parameters, Michael P. Hickey Ph.D., J. S. Brown
A Simulation Study Of Space-Based Observations Of Gravity Waves In The Airglow Using Observed Aloha-93 Wave Parameters, Michael P. Hickey Ph.D., J. S. Brown
Michael P. Hickey
We use gravity wave parameters derived from the ALOHA-93 campaign to model four gravity waves in airglow emissions as observed from the ground to numerically predict whether these waves could have been observed from space. In spite of encountering critical levels, some waves may still be observed in the airglow provided the critical level lies within the airglow emission region. One of the four waves experiences a critical level in the lower region of an airglow layer such that the disturbance to the volume emission rate would be effectively limited to a short distance along a satellite line of sight. …
Investigating Mesospheric Gravity Wave Dynamics Over Mcmurdo Station, Antarctica, Jonathan R. Pugmire, Mike J. Taylore, Yucheng Zhao, P Dominique Pautet
Investigating Mesospheric Gravity Wave Dynamics Over Mcmurdo Station, Antarctica, Jonathan R. Pugmire, Mike J. Taylore, Yucheng Zhao, P Dominique Pautet
Jonathan Pugmire
The ANtarctic Gravity Wave Instrument Network (ANGWIN) is an NSF sponsored international program designed to develop and utilize a network of gravity wave observatories using existing and new instrumentation operated at several established research stations around the continent. The primary goal is to better understand and quantify large-scale gravity wave climatology and their effects on the upper atmosphere over Antarctica. ANGWIN currently comprises research measurements from five nations (U.S., U.K., Australia, Japan, and Brazil) at seven international stations. Utah State University's Atmospheric Imaging Lab operates an all-sky CCD, all-sky infrared imagers and an Advanced Mesospheric Temperature Mapper (AMTM) imager at …
Timed/Saber Satellite Investigations Of Mesospheric Gravity Wave Variances Over The Andes, Jonathan R. Pugmire
Timed/Saber Satellite Investigations Of Mesospheric Gravity Wave Variances Over The Andes, Jonathan R. Pugmire
Jonathan Pugmire
Focusing on data from the SABER instrument aboard the TIMED satellite temperature variances are determined as a function of altitude to quantify small scale gravity waves. This was done using IDL software to extract all the temperature profile measurements that were measured by SABER within a limited geographical area, centered on our ground-based optical imager at Cerro Pachon, Chile (30.3°S, 70.7°S). Then large-scale tidal waves, with wavenumbers 0-6, were removed from each profile revealing the gravity wave perturbations. The temperature variance were computed and recorded at several altitudes. Temperature variances reveal possible increased activity due to mountain waves. Mountain waves …
New Measurements Of Mcmurdo Gravity Wave Parameters, Jonathan R. Pugmire, Michael J. Taylor, P Dominique Pautet
New Measurements Of Mcmurdo Gravity Wave Parameters, Jonathan R. Pugmire, Michael J. Taylor, P Dominique Pautet
Jonathan Pugmire
The ANtarctic Gravity Wave Instrument Network (ANGWIN) is an NSF sponsored international program designed to develop and utilize a network of gravity wave observatories using existing and new instrumentation operated at several established research stations around the continent. The primary goal is to better understand and quantify large-scale gravity wave climatology and their effects on the upper atmosphere over Antarctica. ANGWIN currently comprises research measurements from five nations (U.S., U.K., Australia, Japan, and Brazil) at seven international stations. Utah State University’s Atmospheric Imaging Lab operates all-sky infrared and CCD imagers and an Advanced Mesospheric Temperature Mapper (AMTM) imager at several …
Initial Measurements Of Mesospheric Gravity Waves Over Mcmurdo, Antarctica, Jonathan R. Pugmire, Michael J. Taylor, Yucheng Zhao, P Dominique Pautet
Initial Measurements Of Mesospheric Gravity Waves Over Mcmurdo, Antarctica, Jonathan R. Pugmire, Michael J. Taylor, Yucheng Zhao, P Dominique Pautet
Jonathan Pugmire
The ANtarctic Gravity Wave Instrument Network (ANGWIN) is an NSF sponsored international program designed to develop and utilize a network of gravity wave observatories using existing and new instrumentation operated at several established research stations around the continent. The primary goal is to better understand and quantify large-scale gravity wave climatology and their effects on the upper atmosphere over Antarctica. ANGWIN currently comprises research measurements from five nations (U.S., U.K., Australia, Japan, and Brazil) at seven international stations. Utah State University’s Atmospheric Imaging Lab operates all-sky infrared and CCD imagers and an Advanced Mesospheric Temperature Mapper (AMTM) imager at several …
Gravity Wave Characteristics In The Lower Atmosphere At South Pole, Matt Pfenniger, Alan Z. Liu, George C. Papen, Chester S. Gardner
Gravity Wave Characteristics In The Lower Atmosphere At South Pole, Matt Pfenniger, Alan Z. Liu, George C. Papen, Chester S. Gardner
Alan Z Liu
A 4-year (1993-1996) temperature and wind data set obtained from over 2000 high-resolution balloon soundings at South Pole is used to study gravity wave characteristics in the atmosphere and lower stratosphere. Extensive analyses of energy density, spectra, and static stability are performed to present a comprehensive view of the gravity waves are ubiquitous and often fairly strong at the South Pole, even though the generation mechanisms are not clear. Gravity wave characteristics are, in general, similar to those obtained at other high-latitude southern hemisphere stations. Potential energies vary between about 0.5 J/kg and 5 J/kg with season and altitude. Variations …
Vertical Dynamical Transport Of Mesospheric Constituents By Dissipating Gravity Waves, Alan Z. Liu, Chester S. Gardner
Vertical Dynamical Transport Of Mesospheric Constituents By Dissipating Gravity Waves, Alan Z. Liu, Chester S. Gardner
Alan Z Liu
Over 400 h of Na wind/temperature lidar observations, obtained at the Star5re Optical Range, NM, are used to study the vertical dynamical transport of Na in the mesopause region between 85 and 100 km. Dynamical transport occurs when dissipating, non-breaking gravity waves impart a net vertical displacement in atmospheric constituents as they propagate through a region. We show that the vertical constituent flux can be related in a simple way to the vertical heat flux. Breaking gravity waves also contribute to eddy transport by generating turbulence. Because eddy transport is a mixing process, it only occurs in the presence of …
Diurnal Variation Of Gravity Wave Momentum Flux And Its Forcing On The Diurnal Tide, Alan Z. Liu, Xian Lu, Steven Franke
Diurnal Variation Of Gravity Wave Momentum Flux And Its Forcing On The Diurnal Tide, Alan Z. Liu, Xian Lu, Steven Franke
Alan Z Liu
Wave-Induced Transport Of Atmospheric Constituents And Its Effect On The Mesospheric Na Layer, Chester S. Gardner, Alan Z. Liu
Wave-Induced Transport Of Atmospheric Constituents And Its Effect On The Mesospheric Na Layer, Chester S. Gardner, Alan Z. Liu
Alan Z Liu
No abstract provided.