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Full-Text Articles in Physics

Gravity Waves Over Antarctica, Vanessa Chambers May 2018

Gravity Waves Over Antarctica, Vanessa Chambers

Physics Capstone Project

As part of the international Antarctic Gravity Wave Instrument Network (ANGWIN) program, the Utah State University all sky IR imager has been operated at the British Antarctic Survey (BAS) Halley Station (75°36′ S, 26°12′ W) since 2012, obtaining valuable gravity wave information in the upper mesosphere and lower thermosphere region (~80 to 100 km). In this study, we have utilized a new 3D spectral analysis technique (Matsuda, et al., 2014) to quantify the horizontal phase velocity distributions of gravity waves over Antarctica. This new tool enables us to analyze extensive amounts of airglow imaging data in a relatively ...


Stratospheric Gravity Wave Fluxes And Scales During Deepwave, Ronald B. Smith, Allison D. Nugent, Christopher G. Kruse, David C. Fritts, James D. Doyle, Steven D. Eckermann, Michael J. Taylor, Andreas Dornbrack, M. Uddstrom, William Cooper, Jorgen Jensen, Stuart Beaton Jul 2016

Stratospheric Gravity Wave Fluxes And Scales During Deepwave, Ronald B. Smith, Allison D. Nugent, Christopher G. Kruse, David C. Fritts, James D. Doyle, Steven D. Eckermann, Michael J. Taylor, Andreas Dornbrack, M. Uddstrom, William Cooper, Jorgen Jensen, Stuart Beaton

All Physics Faculty Publications

During the Deep Propagating Gravity Wave Experiment (DEEPWAVE) project in June and July 2014, the Gulfstream V research aircraft flew 97 legs over the Southern Alps of New Zealand and 150 legs over the Tasman Sea and Southern Ocean, mostly in the low stratosphere at 12.1-km altitude. Improved instrument calibration, redundant sensors, longer flight legs, energy flux estimation, and scale analysis revealed several new gravity wave properties. Over the sea, flight-level wave fluxes mostly fell below the detection threshold. Over terrain, disturbances had characteristic mountain wave attributes of positive vertical energy flux (EFz), negative zonal momentum flux, and ...


Satellite Measurements Of Mesospheric Gravity Wave Temperature Variances Over The Andes, Jonathan Pugmire Jun 2015

Satellite Measurements Of Mesospheric Gravity Wave Temperature Variances Over The Andes, Jonathan Pugmire

Graduate Student Posters

Utah State University’s Mesospheric Temperature Mapper (MTM) has operated continuously at the Andes Lidar Observatory on Cerro Pachon, Chile (30.3° S, 70.7° S) since August 2009. Its purpose is to quantify gravity wave (GW) activity as observed in OH rotational temperature measurements in the mesosphere at an altitude of ~87 km with a particular interest in investigating short period GWs and their seasonal variability. 5.5 years data to date.

The SABER instrument aboard the TIMED satellite provides complimentary data to measure temperature variances and GW potential energy (PE) to quantify the small-scale GWs propagating up into ...


Upgraded Alo Rayleigh Lidar System And Its Improved Gravity Wave Measurements, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Marcus J. Bingham Jun 2012

Upgraded Alo Rayleigh Lidar System And Its Improved Gravity Wave Measurements, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Marcus J. Bingham

Graduate Student Posters

The Rayleigh-Scatter lidar system at the Atmospheric Lidar Observatory (ALO) on the Utah State campus is currently going through a series of upgrades to significantly improve its observational abilities. A specific objective of these upgrades is to expand the altitude range over which backscattered photons can be collected. A second objective is to increase the sensitivity of the instrument to be able to analyze the raw data at finer temporal and/or spatial resolutions. By measuring relative densities, the system will be able to produce absolute temperatures and relative density perturbations, which illustrate gravity wave structures. Gravity wave studies will ...


Observations With The Most Sensitive Rayleigh-Scatter Lidar, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Marcus J. Bingham Apr 2012

Observations With The Most Sensitive Rayleigh-Scatter Lidar, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Marcus J. Bingham

Graduate Student Posters

The mesosphere is the most unexplored region of the atmosphere. Its altitude range of 50-85 km lies in between the reaches of data collecting instruments like weather balloons and satellites. For this reason, remote sensing systems, such as lidar, which are able to employ ground-based instruments to make extensive measurements in this difficult to detect region. The Rayleigh-scatter lidar at USU is currently being redeveloped to be the most powerful and sensitive of its kind. This type of lidar exploits light and particle interactions, like those that account for the blue color of the sky, to make relative density and ...


Rayleigh-Lidar Observations Of Mesospheric Instabilities, Gabriel C. Taylor, Durga N. Kafle, Vincent B. Wickwar Apr 2009

Rayleigh-Lidar Observations Of Mesospheric Instabilities, Gabriel C. Taylor, Durga N. Kafle, Vincent B. Wickwar

Posters

From 1993 to 2004 the Utah State University Rayleigh lidar, known as the USU green laser, collected 900 nights of data from the mesosphere (45-90 km). From these observations profiles of relative neutral densities and absolute temperatures were derived. Usually, the atmosphere is horizontally stratified with a balance between gravitational and pressure forces. When this balance is perturbed, it leads to the generation of buoyancy or “gravity” waves. An example of these is clear air turbulence, which can have dramatic effects on airplanes. As these waves propagate upward, the decrease in atmospheric density and conservation of energy combine to give ...


Investigation Of A "Wall" Wave Event, F. Li, G. R. Swenson, A. Z. Liu, Michael J. Taylor, Y. Zhao Feb 2007

Investigation Of A "Wall" Wave Event, F. Li, G. R. Swenson, A. Z. Liu, Michael J. Taylor, Y. Zhao

All Physics Faculty Publications

A bright airglow event was observed at Maui, Hawaii, on the night of 11–12 August 2004 with multiple instruments including a Na wind/temperature lidar, an airglow imager, and a mesospheric temperature mapper. The characteristics of this event were investigated with measurements from these instruments. Analysis showed that this event was caused by a large-amplitude, upward-propagating gravity wave with a period of about 4–5 hours and a vertical wavelength of about 20 km, i.e., a ‘‘wall’’ wave. This wall wave induced dramatic changes in temperature (60 K), airglow intensity (doubled in the OH and tripled in the ...


An Investigation Of Gravity Wave Activity In The Low-Latitude Mesosphere: Propagation Direction And Wind Filtering, A. F. Medeiros, Michael J. Taylor, H. Takahashi, P. P. Batista, D. Gobbi Jul 2003

An Investigation Of Gravity Wave Activity In The Low-Latitude Mesosphere: Propagation Direction And Wind Filtering, A. F. Medeiros, Michael J. Taylor, H. Takahashi, P. P. Batista, D. Gobbi

All Physics Faculty Publications

An all-sky charge-coupled device imager capable of measuring wave structure in the OH, O2, and O I (557.7 nm) airglow emissions was operated at Cachoeira Paulista, Brazil (23S, 45W), for 2 years in collaboration with Utah State University, Logan. The dominant quasi-monochromatic gravity wave components investigated over a 1 year period (September 1998 to October 1999) have been extracted, and their seasonal variations have been measured. A total of 283 wave events were measured, exhibiting horizontal wavelengths from 5 to 60 km, observed periods from 5 to 35 min, and horizontal phase speeds of up to 80 m s1 ...


Mesospheric Temperature Observationsat The Usu / Cass Atmospheric Lidar Observatory (Alo), Vincent B. Wickwar, T D. Wilkerson, M Hammond, Joshua P. Herron Jan 2001

Mesospheric Temperature Observationsat The Usu / Cass Atmospheric Lidar Observatory (Alo), Vincent B. Wickwar, T D. Wilkerson, M Hammond, Joshua P. Herron

All Physics Faculty Publications

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 ...


Long Base-Line Measurements Of Short Period Mesospheric Gravity Waves During The Seek Campaign, Michael J. Taylor, S. H. Seo, T. Nakamura, T. Tsuda, H. Fukunishi, Y. Takahashi Jun 1998

Long Base-Line Measurements Of Short Period Mesospheric Gravity Waves During The Seek Campaign, Michael J. Taylor, S. H. Seo, T. Nakamura, T. Tsuda, H. Fukunishi, Y. Takahashi

All Physics Faculty Publications

Simultaneous observations of short‐period (<1 hour) mesospheric gravity waves were made over an extended base‐line (∼660 km) from two sites in Japan (at Shigaraki and Yamagawa) during the SEEK (Sporadic‐E Experiment over Kyushu) campaign, 9–23 August, 1996. Coincident image data obtained on four nights provided a rare opportunity to investigate the horizontal spatial extent and propagation characteristics of the waves in detail. Surprisingly, out of a total of 12 events observed from Shigaraki and 10 from Yamagawa at most only three exhibited similar propagation characteristics at each site. The majority of the wave displays (∼70–75%) had quite dissimilar characteristics suggesting a preponderance for localized wave motions of limited lifetimes and geographical extent. A marked preference for wave progression towards the N‐NE indicates that the gravity waves imaged in the near infrared OH and OI (557.7 nm) nightglow emissions were probably not directly associated with the observed E‐region irregularities.


Application Of Tomographic Inversion In Studying Airglow In The Mesopause Region, T. Nygren, Michael J. Taylor, M. S. Lehtinen, M. Markkanen Apr 1998

Application Of Tomographic Inversion In Studying Airglow In The Mesopause Region, T. Nygren, Michael J. Taylor, M. S. Lehtinen, M. Markkanen

All Physics Faculty Publications

It is pointed out that observations of periodic nightglow structures give excellent information on atmospheric gravity waves in the mesosphere and lower thermosphere. The periods, the horizontal wavelengths and the phase speeds of the waves can be determined from airglow images and, using several cameras, the approximate altitude of the luminous layer can also be determined by triangulation. In this paper the possibility of applying tomographic methods for reconstructing the airglow structures is investigated using numerical simulations. A ground-based chain of cameras is assumed, two-dimensional airglow models in the vertical plane above the chain are constructed, and simulated data are ...


Dynamic And Chemical Aspects Of The Mesospheric Na ‘Wall’ Event On 9 October 1993 During The Aloha Campaign, G. R. Swenson, J. Qian, J. M.C. Plane, P. J. Espy, Michael J. Taylor, D. N. Turnbull, R. P. Lowe Apr 1998

Dynamic And Chemical Aspects Of The Mesospheric Na ‘Wall’ Event On 9 October 1993 During The Aloha Campaign, G. R. Swenson, J. Qian, J. M.C. Plane, P. J. Espy, Michael J. Taylor, D. N. Turnbull, R. P. Lowe

All Physics Faculty Publications

On October 9, 1993, observations were made from the National Center for Atmospheric Research Electra aircraft during a flight from Maui, Hawaii, toward a low-pressure system NW of the island, a flight of 7 hours in total. The leading edge (wall) of a bright airglow layer was observed 900 km NW of Maui at 0815 UT, which was traveling at 75 m s−1 toward the SE, reaching Haleakala, Maui, about 3.25 hours later [see Swenson and Espy, 1995]. An intriguing feature associated with the event was the large increase in the mesospheric Na column density at the wall ...


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 Mar 1998

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

All Physics Faculty Publications

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 ...


Image Measurements Of Short Period Gravity Waves At Equatorial Latitudes, Michael J. Taylor, W. R. Pendleton Jr., S. Clark, H. Takahashi, D. Gobbi, R. A. Goldberg Nov 1997

Image Measurements Of Short Period Gravity Waves At Equatorial Latitudes, Michael J. Taylor, W. R. Pendleton Jr., S. Clark, H. Takahashi, D. Gobbi, R. A. Goldberg

All Physics Faculty Publications

A high-performance, all-sky imaging system has been used to obtain novel data on the morphology and dynamics of short-period (<1 hour) gravity waves at equatorial latitudes. Gravity waves imaged in the upper mesosphere and lower thermosphere were recorded in three nightglow emissions, the near-infrared OH emission, and the visible wavelength OI (557.7 nm) and Na (589.2 nm) emissions spanning the altitude range ∼80–100 km. The measurements were made from Alcantara, Brazil (2.3°S, 44.5°W), during the period August-October 1994 as part of the NASA/Instituto Nacional de Pesquisas Espaciais “Guara campaign”. Over 50 wave events were imaged from which a statistical study of the characteristics of equatorial gravity waves has been performed. The data were found to divide naturally into two groups. The first group corresponded to extensive, freely propagating (or ducted) gravity waves with observed periods ranging from 3.7 to 36.6 min, while the second group consisted of waves of a much smaller scale and transient nature. The later group exhibited a bimodal distribution for the observed periods at 5.18 ± 0.26 min and 4.32 ± 0.15 min, close to the local Brunt-Vaisala period and the acoustic cutoff period, respectively. In comparison, the larger-scale waves exhibited a clear tendency for their horizontal wavelengths to increase almost linearly with observed period. This trend was particularly well defined around the equinox and can be represented by a power-law relationship of the form λ h = ( 3.1 ± 0.5 ) τ ob 1.06 ± 0.10 , where λ h is measured in kilometers and τob in minutes. This result is in very good agreement with previous radar and passive optical measurements but differs significantly from the relationship λ h ∝ τ105 ob inferred from recent lidar studies. The larger-scale waves were also found to exhibit strong anisotropy in their propagation headings with the dominant direction of motion toward the-NE-ENE suggesting a preponderance for wave generation over the South American continent.


Two-Dimensional Spectral Analysis Of Mesospheric Airglow Image Data, F. J. Garcia, Michael J. Taylor, M. C. Kelley Oct 1997

Two-Dimensional Spectral Analysis Of Mesospheric Airglow Image Data, F. J. Garcia, Michael J. Taylor, M. C. Kelley

All Physics Faculty Publications

A technique to analyze short-period (<1 hour) gravity wave structure in all-sky images of the airglow emissions is described. The technique involves spatial calibration, star removal, geographic projection, regridding, and flat fielding of the data prior to the determination of the horizontal wave parameters (wavelength, velocity, and period), by use of standard two-dimensional Fourier analysis techniques. The method was developed to exploit the information that is now available with wide-field solid state imaging systems. This technique permits interactive and quantitative investigations of large, complex data sets. Such studies are important for investigating gravity wave characteristics, their interaction with the airglow emissions, and their geographic and seasonal variability. We study one event of this type here and present possible evidence of a nonlinear wave–wave interaction in the upper atmosphere.


Numerical Simulations Of Gravity Waves Imaged Over Arecibo During The 10-Day January 1993 Campaign, M. P. Hickey, R. L. Walterscheid, Michael J. Taylor, W. Ward, G. Schubert, Q. Zhou, F. Garcia, M. C. Kelley, G. G. Shepherd Jun 1997

Numerical Simulations Of Gravity Waves Imaged Over Arecibo During The 10-Day January 1993 Campaign, M. P. Hickey, R. L. Walterscheid, Michael J. Taylor, W. Ward, G. Schubert, Q. Zhou, F. Garcia, M. C. Kelley, G. G. Shepherd

All Physics Faculty Publications

Recently, measurements were made of mesospheric gravity waves in the OI (5577 Å) nightglow observed from Arecibo, Puerto Rico, during January 1993 as part of a special 10-day 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 two waves through the mesopause region and calculated the O(1 S) nightglow response to the waves. Mean winds derived from both UARS wind imaging interferometer (WINDII) and Arecibo incoherent scatter radar observations were employed in the computations as were the ...


Maximum Penetration Of Atmospheric Gravity Waves Observed During Aloha-93, G. R. Swenson, C. S. Gardner, Michael J. Taylor Oct 1995

Maximum Penetration Of Atmospheric Gravity Waves Observed During Aloha-93, G. R. Swenson, C. S. Gardner, Michael J. Taylor

All Physics Faculty Publications

Atmospheric Gravity Waves (AGWs) are subject to altitude propagation limits which are governed by the diffusion processes. Diffusion times and scales which exceed the wave period and wavelength define the limiting domain for AGWs. An expression is presented which defines the upper altitude limit to which AGWs can propagate given vertical diffusion constraints of the atmosphere. Airglow, lidar, and radar measurements are combined to characterize the intrinsic AGW parameters in the 80–105 km altitude region. A subset of AGWs (17) observed by airglow imagers during the ALOHA‐93 were made when simultaneous wind measurements were available and intrinsic wave ...


Determination Of Horizontal And Vertical Structure Of A Novel Pattern Of Short Period Gravity Waves Imaged During Aloha-93, Michael J. Taylor, D. C. Fritts, J. R. Isler Oct 1995

Determination Of Horizontal And Vertical Structure Of A Novel Pattern Of Short Period Gravity Waves Imaged During Aloha-93, Michael J. Taylor, D. C. Fritts, J. R. Isler

All Physics Faculty Publications

An all‐sky CCD imager has been used to measure the properties of short period gravity waves present over the Hawaiian Islands during the ALOHA‐93 campaign. Observations of emissions from four different altitudes provided a capability to describe the vertical as well as the horizontal structure of the wave field. On several occasions during this campaign an unusual morphology wave pattern was detected that consisted of a group of small‐scale waves oriented in the same direction. These were most noticeable in the OI (557.7 nm) emission, altitude ∼96 km, and were usually observed in association with a ...


A Two-Dimensional Spectral Analysis Of Short Period Gravity Waves Imaged In The Oi (557.7 Nm) And Near Infrared Oh Nightglow Emissions Over Arecibo, Puerto Rico, Michael J. Taylor, F. J. Garcia Sep 1995

A Two-Dimensional Spectral Analysis Of Short Period Gravity Waves Imaged In The Oi (557.7 Nm) And Near Infrared Oh Nightglow Emissions Over Arecibo, Puerto Rico, Michael J. Taylor, F. J. Garcia

All Physics Faculty Publications

In January 1993 an extensive set of radar and optical data was gathered from various key sites around the world during a coordinated “10 Day Run” designed to investigate the coupled dynamic behavior of the upper atmosphere on a large, medium and small scale. As part of this campaign an all‐sky CCD imaging system was operated at Arecibo Observatory, Puerto Rico, to help quantify the response of the low latitude mesosphere‐thermosphere system to short period (<1 hour) gravity waves. Measurements of the OI(557.7 nm) and near infrared OH nightglow emissions were made in conjunction with photometric and ISR radar soundings and revealed an abundance of small‐scale structure in the 80–100 km range. In this letter we apply two‐dimensional spectral analysis techniques to aid in the interpretation of a complex set of image data that consisted of two intersecting quasi‐monochromatic gravity wave patterns progressing on approximately orthogonal headings. An investigation of the spectral content and temporal evolution of these wave motions at each emission altitude is presented.