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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. …
Satellite Measurements Of Mesospheric Gravity Wave Temperature Variance Over The Andes, Jonathan R. Pugmire, Michael J. Taylore, Yucheng Zhao
Satellite Measurements Of Mesospheric Gravity Wave Temperature Variance Over The Andes, Jonathan R. Pugmire, Michael J. Taylore, Yucheng Zhao
Jonathan Pugmire
Focusing on over 10 years of data from the SABER instrument aboard the TIMED satellite temperature variances are determined to quantify the signatures of short-period gravity waves propagating up into the mesosphere, and lower thermosphere (MLT) region. Temperature profile measurements were measured by SABER within a limited geographical area, centered on the Andes Lidar Observatory at Cerro Pachon, Chile (30.3° S, 70.7° S) where Utah State University has operated an OH Mesospheric Temperature Mapper (MTM) for the past 5 years. Using an established procedure the large-scale tidal waves, with wavenumbers 0-6, were removed from each profile revealing the gravity wave …
Observations Of Mesospheric Gravity Waves Over The Andes, Jonathan Pugmire
Observations Of Mesospheric Gravity Waves Over The Andes, Jonathan Pugmire
Jonathan Pugmire
Focusing on data from an imager and the SABER instrument aboard the TIMED satellite temperature variances are determined to quantify small-scale gravity waves. IDL software was used 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). Large-scale tidal waves, with wavenumbers 0-6, were removed from each profile revealing the gravity wave perturbations. Temperature variances reveal possible increased wave activity due to mountain waves. Mountain waves in the mesosphere are a relatively unexplored field in aeronomy. They are generated predominantly in …