Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"mesopause"”.
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Gravity Wave and Turbulence Transport in the Mesopause Region
… dissipating gravity waves and turbulence in the mesopause region (85-100 km) are analyzed with observational data obtained from a narrow-band sodium wind/temperature lidar located at Andes Lidar Observatory (ALO), Cerro Pach´on (30.25 S, 70.73 W), Chile. The Na lidar at ALO has been in regular …
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Modelling Mesopause OH* Emissions using a Global Circulation Model
Nightglow within the mesopause region of the atmosphere is dominated by the infrared emissions from vibrationally excited hydroxyl (OH*) radicals at ~87km altitude. These emissions provide a signal from which the behaviour of the middle atmosphere can be studied and in recent years a wealth of …
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Lidar studies of gravity waves in the mesopause region
… variations in gravity wave activity in the mesopause region are examined by analyzing 60 nights of Na lidar observations obtained during a five-year period at Urbana, Illinois. The lidar data were used to calculate atmospheric density perturbations and their spectra. The atmospheric density …
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Dynamics of Atmospheric Gravity Wave Breaking in the Mesopause Region
… of wave breaking and their effects in the mesopause region above Andes Lidar Observatory (30.2◦ S, 70.7◦ W). A few scientific topics related to GW break- ing are addressed. What are the probabilities of the atmosphere becoming convectively or dynamically unstable in the mesopause region and …
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Studies of Atmospheric Gravity Waves in the Mesopause Region Using Airglow Imaging
To explore the potential of studying wave propagation through airglow layers using imaging systems, numerical simulations have been carried out to retrieve vertical structures from multisensor imaging measurements. Regularization techniques have been compared in the tomographic reconstruction …
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Gravity Waves Studies in Mesopause Region by Using Na Wind/temperature Lidar
… used to study heat flux and cooling rate over mesopause region by directly measuring vertical wind and temperature. The various error sources are analyzed. The heat flux and cooling rate show considerable variability. The measured heat flux and cooling rate are consistent with theoretical …
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Gravity waves and ripples near the mesopause above Davis Station, Antarctica. 1999-2013
… gravity waves (GWs) and ripples near the mesopause (~87 km altitude). The main findings are as follows: 1. Two distinct distributions of horizontal wavelength were observed both obeying the relation
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Gravity Wave Characteristics in the Troposphere, Lower Stratosphere, and Mesopause at the South Pole
… examine the troposphere, lower-stratosphere, and mesopause. It is found that wave strength in the lower atmosphere is always less energetic than at low- and midlatitude sites. In austral winter, wave amplitudes are about one-fourth their summertime values. Wave amplitudes in the mesopause are as …
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A Dynamical Study of Gravity Waves and Instabilities in the Mesopause Region at Maui, Hawaii
A ray-tracing simulation was performed to explore whether the interactions between tides and oppositely-propagating waves could explain the observed double-layer structure of large N2/strong wind shear. It is found, using the GROGRAT model, that tidal modulation has two effects on the wave …
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An Observational Investigation on Gravity Wave Characteristics and Propagation in the Lower Stratosphere and Mesopause
… high-resolution radiosonde at South Pole and the mesopause region using OH airglow imager at Maui, Hawaii and Cerro Pachon, Chile. Wave characteristics at these regions are deduced and the seasonal variation of wave activity, wave sources, and propagation effect are studied. The study of gravity …
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Stability of the Mesopause Region: Influence of Dissipating Gravity Waves on the Transport of Heat, Momentum and Constituents
… wind and temperature observations in the mesopause region (80--105 km) were obtained at the Starfire Optical Range (35°N, 106.5°W), NM during 94--95 period and 98--99 period. The structure and seasonal variations of static and dynamic instabilities are examined using horizontal …
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Lidar studies of sporadic sodium layers, gravity waves and density spectra in the mesopause and stratopause regions at Urbana and Arecibo
The high spatial and temporal resolution of the UIUC CEDAR lidar and new processing techniques have significantly improved the study of vertical and temporal structures of the middle atmosphere. This thesis paper first presents what are believed to be the first observations of meteor ablation …
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Seasonal and Diurnal Variations in the Temperature and Sodium Density Structure of the Middle Atmosphere
… associated with dissipating gravity waves. The mesopause (altitude of minimum temperature) is controlled by two independent seasonal changes in the thermal structure. The mesopause occupies a high state (>96 km) during most of the year, when it is determined by in situ thermospheric heating, …
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Role of Planetary Wave-Tide-Gravity Wave Interactions In Whole Atmosphere Coupling
… of IHCs. Warmings around the summer polar mesopause are more pronounced in the later boreal winter sub-seasons compared to the earlier sub-season. In addition to typical IHC patterns, a cooling below the summer mesopause at SH high latitudes is found during late boreal winter sub-seasons …
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Rocket Borne Measurements of a Near-Infrared Vehicle Induced Emission with a Newly Designed Spectrograph
… as well as the vehicle induced glow through the mesopause at eight discreet bandpasses. Data collected shows moderate agreement with previous measurements by Murtagh et al. [1997] and Lopez-Moreno et al. [1985] over similar wavelengths. With this data we attempt to show some correlations between …
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Middle atmosphere structure and dynamics: Lidar studies at the South Pole, Syowa and Urbana
… 1990 and Syowa in 1985 are used to characterize mesopause region gravity wave activity over Antarctica. The structure of the Na layer reflects the general circulation of the high-latitude mesopause. The monochromatic waves observed over Antarctica show the same general characteristics as those …
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Planetary Wave Activity Observed in Polar Mesospheric Clouds
… transport of water vapor into the summer polar mesopause and dynamically forced small scale temperature fluctuations. This result is concluded from coupling past research observing planetary waves in vertical and horizontal winds, water vapor, and temperature fluctuations.</p>
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