Physical Sciences and Mathematics Commons^™

Tidal Perturbations And Variability In Mesopause Region Over Fort Collins, Co(41n, 105w): Continuous Multi-Day Temperature And Wind Lidar Observations, C. Y. She, T. Li, R. L. Collins, Tao Yuan, B. P. Williams, T. Kawahara, J. D. Vance, P. Acott, D. A. Krueger, H. L. Liu, M. E. Hagan

All Physics Faculty Publications

An unusually long data set was acquired at the sodium lidar facility at Colorado State University (41N, 105W), between Sep 18 and Oct 01, 2003, including a 9-day continuous observation. This time is long enough to average out the perturbations of gravity waves and short-period planetary waves. As such, it can be used to define tidal-period perturbations in temperature and horizontal wind. Assuming the sodium mixing ratio is a constant of motion, the observed tidal-period oscillation in sodium density follows that of vertical wind. Thus, the data set defines tidal-period perturbations of temperature and wind vector. The observed amplitudes and …

Comparisons Of Long-Term Trends And Variability In The Middle Atmosphere, Troy Wynn, Joshua P. Herron, Vincent B. Wickwar

Posters

The USU Rayleigh Lidar (41.74°N 111.81°W) has been regularly used to measure temperatures in the middle atmosphere from 45 to 90 km. It is well suited for nightly observation; provides excellent vertical temperature resolution; and does not need external calibration. It began operation in August 1993 and a dataset spanning more than ten years has been collected. The analysis here includes 593 nightly temperature profiles from September 1993 through July 2003.

With many sources of variation in the atmosphere, all temperature effects cannot be easily detected. The largest source of temperature variation, and the easiest to measure, is the annual …

Rayleigh-Lidar Observations Of Mesospheric Mid-Latitude Density Climatology Above Utah State University, Eric M. Lundell, Vincent B. Wickwar

Posters

Data from Rayleigh lidars have been used extensively to derive temperatures in the mesospheric region of the atmosphere. However, these data have not been used extensively in a similar way to derive neutral densities. We report on one such mid-latitude, density climatology between 45 and ~90 km, based on nearly 600 good nights of observations carried out since 1993 at the Atmospheric Lidar Observatory (ALO) at Utah State University (41.7°N 111.8°W). They produce relative density profiles that are then normalized at 45 km to an empirical model, in this case the MSISe00 model. Despite this normalization, significant differences are found …

Seasonal Variations Of The Gravity Wave Momentum Flux In The Antarctic Mesosphere And Lower Thermosphere, P. J. Espy, G. O.L. Jones, G. R. Swenson, J. Tang, Michael J. Taylor

All Physics Faculty Publications

Airglow imager and dynasonde/imaging Doppler interferometer (IDI) radar wind measurements at Halley Station, Antarctica (75.6S, 26.6W) have been used to estimate the seasonal variation of the vertical fluxes of horizontal momentum carried by highfrequency atmospheric gravity waves. The cross-correlation coefficients between the vertical and horizontal wind perturbations were calculated from sodium (Na) airglow imager data collected during the austral winter seasons of 2000 and 2001. These were combined with wind velocity variances from coincident radar measurements to estimate the daily averaged upper limit of the vertical flux of horizontal momentum due to gravity waves. The resulting momentum flux at the …

Concurrent Oh Imager And Sodiumtemperature/Wind Lidar Observation Of A Mesopause Region Undular Bore Event Over Fort Collins/Platteville, Co, C. Y. She, T. Li, B. P. Williams, Tao Yuan, R. H. Picard

All Physics Faculty Publications

We reported the observation of a mesospheric front with the properties of an undular bore by an OH imager, over the Fort Collins/Platteville area on 6/7 October 2002. Unlike the earlier bore observations, a Na lidar capable of measuring mesopause region temperature, zonal, and meridional winds was in operation concurrently. The lidar data confirm, for the first time, the existence of a collocated temperature inversion layer to serve as the ducting region for bore propagation, as required by the simple theory proposed by Dewan and Picard 6 years ago. In addition, the lidar data in principle provide sufficient information for …

Proposed Experimental Actions For Water Years 2005-2006 Colorado River, Arizona, In Glen Canyon National Recreation Area And Grand Canyon National Park, U.S. Department Of The Interior, Bureau Of Reclamation, National Park Service, U.S. Geological Survey

All U.S. Government Documents (Utah Regional Depository)

In September 2002 the Bureau of Reclamation, National Park Service (NPS), and U.S. Geological Survey released an environmental assessment (EA) on proposed experimental releases from Glen Canyon Dam and removal of non‐native fish from the Colorado River in Grand Canyon, Arizona (Bureau of Reclamation, NPS, and USGS 2002). The experiment was developed by the Grand Canyon Monitoring and Research Center of the U.S. Geological Survey (GCMRC), cooperating scientists, and the Technical Work Group (TWG) of the Glen Canyon Dam Adaptive Management Program (GCDAMP). It was recommended to the Secretary of the Interior by the Adaptive Management Work Group (AMWG), a …

Average Nighttime F Region Disturbance Neutral Winds Measured By Windi Uars: Initial Results, J. T. Emmert, Bela G. Fejer, G. G. Shepard, B. H. Solheim

Bela G. Fejer

[1] We use low- and mid-latitude wind data from the Wind Imaging Interferometer (WINDII) on board the Upper Atmosphere Research Satellite (UARS) to study the average response of nighttime upper thermospheric winds to geomagnetic activity. We calculate perturbation winds in magnetic coordinates and analyze them as a function of magnetic local time, latitude, geomagnetic activity, and solar EUV flux. The nighttime zonal disturbance winds are predominately westward, with the strongest effects extending from dusk at 70° to midnight at 45°. Westward disturbance winds are also observed throughout most of the night at low latitudes, where they change to eastward at …

The Effect Of Low Energy Electron And Uv/Vis Radiation Aging On The Electron Emission Properties And Breakdown Of Thin-Film Dielectrics, John R. Dennison, C. D. Thomson, Alec Sim

All Physics Faculty Publications

Studies of secondary and backscattered electron yield curves of thin-film dielectrics have recently been made using pulsed, low current electron beam methods to minimize insulator charging. These capabilities have allowed us to investigate the evolution of surface and internal charge profiles as a function of low energy electron (keV) pulsed-electron fluence to determine how quickly insulators charge, and how this can affect subsequent electron emission properties. We have also studied critical incident electron energies that result in electrical breakdown of insulator materials and the effect of breakdown on subsequent emission, charging and conduction. The qualitative physics of such processes in …

Event Rate Estimates For Lisa Extreme Mass Ratio Capture Sources, J. Gair, L. Barack, T. Creighton, C. Cutler, Shane L. Larson, E. S. Phinney, M. Vallisneri

All Physics Faculty Publications

One of the most exciting prospects for the LISA gravitational wave observatory is the detection of gravitational radiation from the inspiral of a compact object into a supermassive black hole. The large inspiral parameter space and low amplitude of the signal make detection of these sources computationally challenging. We outline here a first-cut data analysis scheme that assumes realistic computational resources. In the context of this scheme, we estimate the signal-to-noise ratio that a source requires to pass our thresholds and be detected. Combining this with an estimate of the population of sources in the universe, we estimate the number …

An Earlier Lidar Observation Of A Noctilucent Cloud Above Logan, Utah (41.7°N), Joshua P. Herron, Vincent B. Wickwar

Posters

The Atmospheric Lidar Observatory (ALO) Rayleigh-scatter lidar has been operated for 11 years on the Utah State University (USU) campus (41.7o N 111.8o W). During the morning of 22 June 1995 a noctilucent cloud (NLC) was observed with the lidar well away from the twilight periods when NLCs are visible. It lasted for approximately one hour. This observation and a second in 1999 [Wickwar et al., 2002] are very significant because they show the penetration of NLCs equatorward of 50°, which may have important implications for global change. Temperature profiles calculated at hourly intervals were at least 20 …

Results From The Middle Atmosphere With The Rayleigh-Scatter Lidar At Usu’S Atmospheric Lidar Observatory, Vincent B. Wickwar, Joshua P. Herron, Troy A. Wynn, Eric M. Lundell

Posters

No abstract provided.

Measurement Of Charge Storage Decay Time And Resistivity Of Spacecraft Insulators, Prasanna V. Swaminathan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Insulators used in the construction of spacecraft are irradiated with high-energy electrons in the space environment and this sometimes causes the insulators to charge to very high voltages. Such charged insulators can generate spontaneous electric partial-discharge pulses of the order of mA to tens of A. These pulses sometimes last enough time to destroy the expensive micro-circuitry present in the spacecraft. In evaluating the threat to the spacecraft due to these discharges, calculation of the resistivity becomes a critical parameter since it determines how accumulated charge will distribute across the spacecraft and how rapidly charge imbalance will dissipate. So far, …

First Nearglobal Retrievals Of Oh Rotational Temperatures From Satellite-Based Meinel Band Emission Measurements, C. Von Savigny, C. U. Eichmann, E. J. Llewellyn, H. Bovensmann, J. P. Burrows, M. Bittner, K. Hoppner, D. Offermann, Michael J. Taylor, Y. Zhao, W. Steinbrecht, P. Winkler

All Physics Faculty Publications

For the first time near-global retrievals of mesopause OH rotational temperatures from satellite-borne Meinel band emission measurements are presented. The measurements of the OH (3-1) Meinel band near 1.5 micron were performed with the SCIAMACHY instrument on the European Space Agency’s environmental satellite Envisat. The derived OH (3-1) rotational temperatures are shown to be in reasonable agreement with the CIRA (1986) atmosphere temperatures for the seasons and latitudes considered. The derived temperatures are in good agreement with groundbased measurements of the OH rotational temperature performed with a CEDAR Mesospheric Temperature Mapper (MTM) at Maui, Hawaii (21N/204E), with the GRound based …

Pastoral Risk Management In Southern Ethiopia: Observations From Pilot Projects Based On Participatory Community Assessments, D. Layne Coppock, Solomon Desta, Seyoum Tezera, Rancis K. Lelo

Environment and Society Faculty Publications

The Borana pastoral system has come under increasing pressure as human populations grow and per capita availability of resources declines. Livestock exhibit large, periodic die-offs that threaten wealth accumulation and food security. Several types of interventions may improve risk management here. For example, there may be opportunity for some pastoralists to diversify their livelihoods. Here we report on a community-based process involving pilot projects begun since 2000. We have embraced Participatory Rural Appraisal (PRA) and Action Research (AR) as tools for investigation and empowerment of local people. Full PRAs were conducted for semi-settled communities, located near towns, to identify priority …

Planetary Waves And Tides Found Using Lomb-Scargle Periodogram Analysis Of Rayleigh-Scatter Data Above Utah State University, Karen L. Nelson, Joshua P. Herron, Vincent B. Wickwar

Posters

Because of the significant gaps in nighttime-only data, traditional Fourier techniques are difficult to use to identify tides and short-period planetary waves (PWs). The Lomb-Scargle per- iodogram is a method that was developed by as- tronomers to identify oscillations in nighttime-only and otherwise incomplete data. For the same rea- sons, it is also a powerful tool for aeronomers. The Lomb-Scargle technique is described with particular emphasis on its application to nighttime- only lidar data. Because of the gaps in the data, attention is also placed on techniques used to identify aliasing in the Lomb-Scargle periodo- grams. The method is applied …

Comparisons Of Long-Term Trends And Variability In The Middle Atmosphere, Troy Wynn, Joshua P. Herron, Vincent B. Wickwar

Posters

Rayleigh Lidar is routinely used to measure temperatures in the middle atmosphere from 45 to 90 km. It is well adapted for nightly observation, provides excellent vertical temperature resolution, and does not need external calibration. The USU Rayleigh Lidar (41.74°N 111.81°W) dataset spans more than ten years from September 1993 to July 2003 with 62 monthly profiles (about 5 years of data) spread over that period.

With many sources of variation in the atmosphere, all temperature effects cannot be detected. The largest source, and the easiest to measure, is the seasonal variation. In addition there are semiannual variation, secular trends, …

Thunderstorm And Lightning Characteristics Associated With Sprites In Brazil, O. Pinto Jr., M. M.F. Saba, I. R.C.A. Pinto, F. S.S. Tavares, K. P. Naccarato, N. N. Solorzano, Michael J. Taylor, P. D. Pautet, R. H. Holzworth

All Physics Faculty Publications

A study of the thunderstorm and cloud-ground lightning characteristics associated with sprite events observed in Brazil is presented. The study is based on ground and aircraft sprite observations with high sensitivity intensified CCD cameras of six different thunderstorms, GOES satellite infrared images, radar and lightning network data. A total of eighteen transient optical events were recorded at three different days in 2002 and 2003, sixteen of which exhibited vertical structures typically associated with sprites. Four thunderstorms were associated with two different cold fronts, one with a Mesoscale Convective System, and one was a local isolated thunderstorm. The sprites occurred during …

Mesospheric Mid-Latitude Density Climatology Above Utah State University, Eric M. Lundell, Vincent B. Wickwar

Posters

Lidars have been used extensively to derive temperatures, but not absolute densities, in the mesospheric region of the atmosphere. We used observations since 1993 with the Rayleigh- scatter lidar at the Atmospheric Lidar Observatory (ALO) at Utah State University (41.7oN, 111.8oW) to create an absolute density climatology between 45 and ~95 km. The observations provide profiles of relative density to which an absolute scale is attached by normalizing the profiles at 45 km to the densities in the MSISe00 empirical model. We examine the density variations on several time scales—during the climatological year, from year to year, and over several …

Another Noctilucent Cloud At 41.7ºn, Joshua P. Herron, Vincent B. Wickwar

Posters

On June 23, 1995, a noctilucent cloud (NLC) was detected with the Rayleigh-scatter lidar at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University (USU) located in Logan, UT (41.7° N 111.8° W). This observation preceded, by four years, the one from 1999 that was previously reported [Wickwar et al., 2002]. These are both important because of their occurrence significantly equatorward of 50° latitude. The NLC was observed for 45 minutes shortly after local midnight. This was well past the twilight period when NLCs are visible to the naked eye. Several parameters of the NLC were …

Atmospheric Lidar Observatory (Alo) Ten-Year Mesospheric Temperature Climatology, Joshua P. Herron, Vincent B. Wickwar

Posters

The Rayleigh-scatter lidar at the Atmospheric Lidar Observatory (ALO) on the Utah State University (USU) (41.7°N, 111.8°W) campus has been in operation since 1993. The temperature database now contains over ten years of Rayleigh-scatter temperatures. A multi-year temperature climatology has been calculated from these observations along with the RMS and interannual variability. These temperatures and the climatology are currently being used in a number of mesospheric studies, including mesospheric inversion layers, tides, planetary waves, cyclical variations, trends, longitudinal comparisons, and validation studies.

Examples Of Alo Results, Vincent B. Wickwar, Joshua P. Herron, Karen M. Nelson, Troy A. Wynn, Kristina Thomas, Eric M. Lundell

Presentations

No abstract provided.

Analysis Of Phytoplankton Nutrient Limitation In Farmington Bay And The Great Salt Lake, Wayne A. Wurtsbaugh, Amy M. Marcarelli

Watershed Sciences Faculty Publications

The Great Salt Lake is bordered to the south and east by a growing metropolitan area that contributes high nutrients to Farmington Bay. This large bay is eutrophic, and there is concern that continued increases in effluents from the Salt Lake City area could extend to impact the much larger, and currently less productive, Gilbert Bay. This study focused on determining how nutrient supplies might limit, and therefore control, algal populations in Farmington Bay and Gilbert Bay at different salinities. We tested both short and long-term responses of algal growth using laboratory nutrient addition bioassays in the summer and fall …

Conservation Assessment Of Greater Sage-Grouse And Sagebrush Habitats, J. W. Connelly, S. T. Knick, M. A. Schroeder, S. J. Stiver, Western Association Of Fish And Wildlife Agencies

All U.S. Government Documents (Utah Regional Depository)

No abstract provided.

Tidal Modulation Of The Gravitywave Momentum Flux In The Antarctic Mesosphere, P. J. Espy, G. O.L. Jones, G. R. Swenson, J. Tang, Michael J. Taylor

All Physics Faculty Publications

Airglow imager and dynasonde/IDI radar wind measurements at Halley Station, Antarctica (76S, 27W) have been used to estimate the diurnal variation of the vertical fluxes of horizontal momentum carried by highfrequency atmospheric gravity waves. The cross-correlation coefficients between the vertical and horizontal wind perturbations were calculated from the sodium airglow imager data collected during four consecutive nights of near total darkness during July of 2000. These were combined with wind-velocity variances from coincident radar measurements to estimate the upper limit of the vertical flux of horizontal momentum during three-hour intervals throughout the period. The resulting momentum flux showed a marked …

Plasma Blobs Observed By Ground-Based Optical And Radio Techniques In The Brazilian Tropical Sector, A. A. Pimenta, Y. Sahai, J. A. Bittencourt, M. A. Abdu, H. Takahashi, Michael J. Taylor

All Physics Faculty Publications

Ground-based optical and radio observations were carried out in the tropical region in Brazil, during the period from October 1998 to September 2000, and on several occasions we detected F-region plasma blob (localized discrete plasma density enhancement) events. These are the first observations of blobs in the tropical F-region using combined ground-based optical and radio techniques. Allsky images were used to map the spatial extension and temporal location of plasma blobs and ionosonde and photometer measurements were used to measure the plasma densities. Interesting cases of plasma blob events were observed on October 07, 1999 and March 04, 2000 over …

Biconformal Supergravity And The Ads/Cftconjecture, L. B. Anderson, James Thomas Wheeler

All Physics Faculty Publications

Biconformal supergravity models provide a new gauging of the superconformal group relevant to the Maldacena conjecture. Using the group quotient method to biconformally gauge SU(2,2|N), we generate a 16-dim superspace. We write the most general even- and odd-parity actions linear in the curvatures, the bosonic sector of which is known to descend to general relativity on a 4-dim manifold.

Computational Scattering Models For Elastic And Electromagnetic Waves In Particulate Media, Timothy Edwin Doyle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Numerical models were developed to simulate the propagation of elastic and electromagnetic waves in an arbitrary, dense dispersion of spherical particles. The scattering interactions were modeled with vector multipole fields using pure-orbital vector spherical harmonics, and solved using the full vector form of the boundary conditions. Multiple scattering was simulated by translating the scattered wave fields from one particle to another with the use of translational addition theorems, summing the multiple-scattering contributions, and recalculating the scattering in an iterative fashion to a convergent solution. The addition theorems were rederived in this work using an integral method, and were shown to …

An Invasive Species Assessment Protocol: Evaluating Non-Native Plants For Their Impact On Biodiversity, Version 1, Larry E. Morse, John M. Randall, Nancy Benton, Ron Hiebert, Stephanie Lu, Natureserve

All U.S. Government Documents (Utah Regional Depository)

NatureServe, in cooperation with The Nature Conservancy and the U.S. National Park Service, developed this Invasive Species Assessment Protocol as a tool for assessing, categorizing, and listing non-native invasive vascular plants according to their impact on native species and natural biodiversity in a large geographical area such as a nation, state, province, or ecological region. This protocol is designed to make the process of assessing and listing invasive plants objective and systematic, and to incorporate scientific documentation of the information used to determine each species’ rank. NatureServe’s methodology has previously included assessments of the conservation significance of native species; this …

The Robustness Of Factor Analyses When The Data Does Not Conform To Standard Parametric Requirements, Haisong Peng

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Objective: To access the robustness of factor analyses when the data does not conform to standard parametric requirements.

Methods: Data were simulated in package R. Maximum likelihood was used to fit and assess the factor models. Chi-square statistics were obtained to test hypotheses about the correct number of factors in simulated settings where the true number of factors was known. The number of true factors varied between 1 and 3; the number of observed variables was either 6 (for 1 factor) or 3 per factor for 2 or more factors.

Results: With standard normal factor populations, and normal errors added …

Lidar Observations Of Oscillations In The Middle Atmosphere, Karen L. M. Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The three major types of oscillations in the atmosphere are gravity waves, planetary waves, and tides. Identifying planetary waves and tides in nighttime-only lid are data is a challenge. The Lomb-Scargle method offers a possible solution to this problem, although aliasing is still a problem when tides are present in the data. The method has been applied to mesospheric Rayle high-scalier lidar temperature data taken at the Utah State University Atmospheric Lidar Observatory (ALO). This analysis is greatly enhanced by the length and completeness of the data set available through ALO, especially with regard to the identification of planetary waves. …