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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
All Physics Faculty Publications
Local full diurnal coverage of temperature variations across the turbopause (∼90–115 km altitude) is achieved by combining the nocturnal observations of a Sodium (Na) Doppler lidar on the Utah State University (USU) campus (41.7°N, 248.2°E) and NASA Michelson interferometer for global high-resolution thermospheric imaging (MIGHTI)/Ionospheric connection explorer (ICON) daytime observations made in the same vicinity. In this study, utilizing this hybrid data set during summer 2020 between June 12th and July 15th, we retrieve the temperature signatures of diurnal and semidiurnal tides in this region. The tidal amplitudes of both components have similar vertical variation with increasing altitude: less than …
Characteristics Of Short-Period Wavelike Features Near 87 Km Altitude From Airglow And Lidar Observations Over Maui, J. H. Hecht, A. Z. Liu, R. L. Walterscheid, S. J. Franke, R. J. Rudy, Michael J. Taylor, Pierre-Dominique Pautet
Characteristics Of Short-Period Wavelike Features Near 87 Km Altitude From Airglow And Lidar Observations Over Maui, J. H. Hecht, A. Z. Liu, R. L. Walterscheid, S. J. Franke, R. J. Rudy, Michael J. Taylor, Pierre-Dominique Pautet
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Small-scale (less than 15 km horizontal wavelength) wavelike structures known as ripples are a common occurrence in OH airglow images. Recent case studies attribute their origin to the presence of either convective or dynamical instabilities. However, little is known about their frequency of occurrence and period. The Maui-MALT Observatory, located at Mt. Haleakala, is instrumented with a Na wind/temperature lidar, which allows the determination of whether the atmosphere is dynamically or convectively unstable, and a fast OH airglow camera which takes images every 3 s with a sensitivity high enough to see the ripples. This study reports on 2 months …
Large Amplitude Perturbations In Mesospheric Oh Meinel And 87-Km Na Lidar Temperatures Around The Autumnal Equinox, Michael J. Taylor, W. R. Pendleton Jr., H. L. Liu, C. Y. She, Larry Gardner, R. G. Roble, V. Vasoli
Large Amplitude Perturbations In Mesospheric Oh Meinel And 87-Km Na Lidar Temperatures Around The Autumnal Equinox, Michael J. Taylor, W. R. Pendleton Jr., H. L. Liu, C. Y. She, Larry Gardner, R. G. Roble, V. Vasoli
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Two high‐precision CEDAR instruments, an OH Mesospheric Temperature Mapper (MTM) and a Na Temperature Lidar, have been used to investigate seasonal variability in the mid‐latitude temperature at ∼87 km altitude over the western USA. Here we report the observation of a large perturbation in mesospheric temperature that occurs shortly after the autumnal equinox in close association with the penetration of planetary‐wave energy from the troposphere into the mesosphere. This perturbation has been observed on three occasions and exhibits a departure of up to ∼25–30 K from the nominal seasonal trend during a disturbed period of ∼2 weeks. Such behavior represents …
Mesospheric Temperature Observationsat The Usu / Cass Atmospheric Lidar Observatory (Alo), Vincent B. Wickwar, T D. Wilkerson, M Hammond, Joshua P. Herron
Mesospheric Temperature Observationsat The Usu / Cass Atmospheric Lidar Observatory (Alo), Vincent B. Wickwar, T D. Wilkerson, M Hammond, Joshua P. Herron
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The Center for Atmospheric and Space Sciences (CASS) at Utah State University (USU) operates the ALO for studying the middle atmosphere from the stratosphere to the lower thermosphere. ALO’s mid-latitude location (41.74°N, 111.81°W, 1466 m) is very unique in that it is in the middle of an extensive set of rugged mountains, the Rocky Mountains, which are a major orographic source of gravity waves that may give rise to a longitudinal variation in the mesospheric structure. Mesospheric observations between approximately 45 and 90 km have been carried out on many clear nights with the ALO Rayleigh- scatter lidar since late …
Full-Wave Modeling Of Small-Scale Gravity Waves Using Airborne Lidar And Observations Of The Hawaiian Airglow (Aloha-93) O(1s) Images & Coincident Na Wind/Temperature Lidar Measurements, M. P. Hickey, Michael J. Taylor, C. S. Gardner, C. R. Gibbons
Full-Wave Modeling Of Small-Scale Gravity Waves Using Airborne Lidar And Observations Of The Hawaiian Airglow (Aloha-93) O(1s) Images & Coincident Na Wind/Temperature Lidar Measurements, M. P. Hickey, Michael J. Taylor, C. S. Gardner, C. R. Gibbons
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Measurements were made of mesospheric gravity waves in the OI (5577 Å) nightglow observed from Maui, Hawaii, during the Airborne Lidar and Observations of Hawaiian Airglow (ALOHA-93) campaign. Clear, monochromatic gravity waves were observed on several nights. By using a full-wave model that realistically includes the major physical processes in this region, we have simulated the propagation of four waves through the mesopause region and calculated the O(1 S) nightglow response to the waves. Mean winds derived from Na wind/temperature lidar observations were employed in the computations. Wave amplitudes were calculated based on the requirement that the observed and simulated …
Observational Limits For Lidar, Radar And Airglow Imager Measurements Of Gravity Wave Parameters, C. S. Gardner, Michael J. Taylor
Observational Limits For Lidar, Radar And Airglow Imager Measurements Of Gravity Wave Parameters, C. S. Gardner, Michael J. Taylor
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By examining the observational limits and biases for lidar, radar, and airglow imager measurements of middle atmosphere gravity waves, we provide plausible explanations for the characteristics of the monochromatic wave parameters that have been reported during the past decade. The systematic dependencies of vertical and horizontal wavelength on wave period, reported in many lidar and some radar studies, are associated with diffusive damping. The prominent waves with the largest amplitudes, most often observed by lidars and radars, are those with vertical phase speeds near the diffusive damping limit. The narrow range of horizontal phase velocities of the waves seen by …
Aloha-93 Measurements Of Intrinsic Agw Characteristics Using The Airborne Airglow Imager And Groundbased Na Wind/Temperature Lidar, G. R. Swenson, Michael J. Taylor, P. Espy, C. S. Gardner, X. Tao
Aloha-93 Measurements Of Intrinsic Agw Characteristics Using The Airborne Airglow Imager And Groundbased Na Wind/Temperature Lidar, G. R. Swenson, Michael J. Taylor, P. Espy, C. S. Gardner, X. Tao
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Monochromatic Acoustic Gravity Waves (AGWs) with periods < 1 hour are a prevalent feature in the mesospheric airglow layers. These waves are important dynamically and energetically to the region where their temporal and spatial morphology are not well established. The purpose of this study is establish the intrinsic AGW characteristics over an extended region (as flown by the NCAR Electra aircraft) and to present the data in terms of the predicted spectral domain defined by the Brunt‐Vaisala frequency and the diffusive filtering limit proposed by Gardner [1994]. On October 21, 1993, observations were made from the NCAR Electra aircraft during a 6 hour flight in a large triangle N and W of Maui, for a integral distance of ∼3000 km. The entire area observed [∼1 M km²] had a monochromatic AGW propagating toward the NW and the western half had a SW propagating wave superimposed. These waves were also observed with the Michelson interferometer on the aircraft and an airglow imager at the Haleakala location during this time. Intrinsic phase velocities were computed where the Na Wind/Temperature (W/T) lidar at Haleakala provided a measure of the mean wind to compensate phase velocities observed with the imager. The data were tabulated and plotted in an AGW spectral reference frame and compared to cutoff conditions predicted by diffusive filtering theory.
An Investigation Of Intrinsic Gravity Wave Signatures Using Coordinated Lidar And Nightglow Image Measurements, Michael J. Taylor, Y. Y. Gu, X. Tao, C. S. Gardner, M. B. Bishop
An Investigation Of Intrinsic Gravity Wave Signatures Using Coordinated Lidar And Nightglow Image Measurements, Michael J. Taylor, Y. Y. Gu, X. Tao, C. S. Gardner, M. B. Bishop
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Simultaneous observations of gravity waves using an Na wind/temperature lidar and a multi‐wavelength all‐sky nightglow imager were obtained, for the first time, during the ALOHA‐93 campaign. A novel investigation of intrinsic wave parameters has been made by combining measurements of the horizontal wave components imaged in four nightglow emissions (height range ∼80–100 km) with Na lidar soundings of the horizontal wind field and temperature profiles over the same height interval. On October 19 both instruments registered marked monochromatic wave motions. The intrinsic periods of several of these waves have been determined and were found to vary considerably with altitude, often …