Physical Sciences and Mathematics Commons^™

Polar F-Layer Model-Observation Comparisons: A Neutral Wind Surprise, Jan Josef Sojka, M. David, Robert W. Schunk, A. P. Van Eyken

All Physics Faculty Publications

The existence of a month-long continuous database of incoherent scatter radar observations of the ionosphere from the EISCAT Savlbard Radar (ESR) at Longyearbyen, Norway, provides an unprecedented opportunity for model/data comparisons. Physics-based ionospheric models, such as the Utah State University Time Dependent Ionospheric Model (TDIM), are usually only compared with observations over restricted one or two day events or against climatological averages. In this study, using the ESR observations, the daily weather, day-to-day variability, and month-long climatology can be simultaneously addressed to identify modeling shortcomings and successes. Since for this study the TDIM is driven by climatological representations of the …

Ionospheric Weather Forecasting On The Horizon, Robert W. Schunk, L. Scherliess, Jan Josef Sojka, D. C. Thompson, L. Zhu

All Physics Faculty Publications

Models of the ionosphere using state-of-the-art data assimilation techniques are nearing operational use.

Importance Of Accurate Computation Of Secondary Electron Emission For Modelingspacecraft Charging, Sebastien Clerc, John R. Dennison

All Physics Faculty Publications

The secondary electron yield is a critical process in establishing the charge balance in spacecraft charging and the subsequent determination of the equilibrium potential. Spacecraft charging codes use a parameterized expression for the secondary electron yield δ(Eo) as a function of incident electron energy, Eo. A critical step in accurately characterizing a particular spacecraft material is establishing the most efficient and accurate way to determine the fitting parameters in terms of the measured electron yield data and physics-based theoretical models. Simple two- or three- step physics models of the electron penetration, transport and emission from a solid are typically expressed …

Proposed Modifications To Engineering Design Guidelines Related To Resistivity Measurements And Spacecraft Charging, John R. Dennison, Prasanna Swaminathan, Randy Jost, Jerilyn Brunson, Nelson W. Green, A. Robb Frederickson

All Physics Faculty Publications

A key parameter in modeling differential spacecraft charging is the resistivity of insulating materials. This parameter determines how charge will accumulate and redistribute across the spacecraft, as well as the time scale for charge transport and dissipation. Existing spacecraft charging guidelines recommend use of tests and imported resistivity data from handbooks that are based principally upon ASTM methods that are more applicable to classical ground conditions and designed for problems associated with power loss through the dielectric, than for how long charge can be stored on an insulator. These data have been found to underestimate charging effects by one to …

Exterior Differential Systems With Symmetry, Ian M. Anderson, Mark E. Fels

Mathematics and Statistics Faculty Publications

We use the theory of reduction of exterior differential systems with symmetry to study the problem of using a symmetry group of a differential equation to find noninvariant solutions.

Field Guide To Exhumed Major Faults In Southern California, Joseph R. Jacobs, Samuel B. Howard, David Forand, Ory Dor, James P. Evans

Geosciences Faculty Publications

This field guide provides an overview of exposures and provides a field trip guide to localities of exhumed faults in southern California. We focus on exposures of faults that are documented or inferred to be exhumed from seismogenic depths. The goal of this guidebook is to provide geoscientists who are interested in fault zone mechanics and earthquake processes a summary of the results of the work on these sites.

Native Or Introduced? Fossil Pollen And Spores May Say. An Example From The Azores Islands, Jacqueline F.N. Van Leeuwen, Hanno Schäfer, W. O. Van Der Knapp, Tammy M. Rittenour, Svante Björck, Brigitta Ammann

Geosciences Faculty Publications

Aim: Among the various possible approaches to assess whether a species is native or introduced, the analysis of subfossil pollen and spores from natural archives is a valuable tool. Requirements include a sufficiently high taxonomic resolution of the pollen morphology, as well as sufficient temporal and spatial resolution. The aim of this study is to show the usefulness of this method in solving whether the taxon is native or introduced.

Location: The results are derived from two islands of the Azores: Flores and Pico. Methods: Analysis of pollen and spores in lake sediments; radiocarbon dating of the studied sediments.

Results: …

Coffee To Go! Modeling Thermoclines In Multivariable Calculus, Andrea Bruder, Brynja R. Kohler

Mathematics and Statistics Faculty Publications

While mathematical modeling is an integral process in applied mathematics, students rarely encounter genuine modeling opportunities in their calculus courses. Here we introduce a laboratory experience as a natural starting point for calculus students to investigate multivariable functions. A layered system of coffee and milk serves as a physical model for temperature gradients in lakes or the atmosphere, where temperature depends on both a temporal and spatial variable. Students create, observe, and collect temperature data of their own, graph the data, and develop mathematical models to fit the data. We require students to write a report about their findings. This …

Evolution Of A Late Cenozoic Supradetachment Basin Above A Flat-On-Flat Detachment With A Folded Lateral Ramp, Se Idaho, A. N. Steely, Susanne U. Janecke, S. P. Long, S. C. Carney, R. Q. Oaks Jr., V. E. Langenheim, P. K. Link

Susanne U. Janecke

Uplift and exposure of the Bannock detachment system and the synextensionalbasin fi ll deposits of the Salt Lake Formation provide a unique exposure of the threedimensionalgeometries of a low-angle normal fault system and the stratal architectureof the overlying supradetachment basin. Within this system, structural andstratigraphic analyses, outcrop patterns, tephra geochronology, and geological crosssections document several important relationships: (1) the Bannock detachment systemdeveloped above the Sevier-age Cache-Pocatello culmination and resembles theSevier Desert detachment in its geometry, structural setting, and kinematic evolution;(2) the Bannock detachment system initiated and slipped at low angles; (3) fl aton-fl at, ramp-fl at, and lateral ramp geometries, …

Five-Year Review Of Executive Order 13112 On Invasive Species, The National Invasive Species Council (Nisc)

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

No abstract provided.

Seepage Study Of Mcleod Creek And East Canyon Creek Near Park City, Summit County, Utah, 2004, C. D. Wilkowske, U.S. Geological Survey, Snyderville Basin Water Reclamation District, U.S. Department Of The Interior

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

Seepage investigations on McLeod Creek downstream of U.S. Geological Survey streamflow-gaging station McLeod Creek near Park City, Utah, and its confluence with Kimball Creek during the summer of 2004 indicate that this section of the creek is a gaining reach. The total seepage gains ranged from 1.8 to 2.7 cubic feet per second, or a 32 to 55 percent gain. The apparent average total seepage gain was 2.2 cubic feet per second, or an average 42 percent gain. Seepage investigations from the U.S. Geological Survey streamflow-gaging station at East Canyon Creek below I-80 Rest Stop near Park City, Utah, to …

Copies Of Unique Comment Letters, Mark Belles, Bureau Of Reclamation

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

Unique letters and messages regarding the "Notice to solicit comments and hold public meetings on the development of management strategies for Lake Powell and Lake Mead, including Lower Basin shortage guidelines, under low reservoir conditions."

Cache County, Utah Resource Assessment, Utah Association Of Conservation Districts, Utah Department Of Agriculture And Foods, Natural Resources Conservation Service

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

This resource assessment is designed to gather and display information specific to Cache County, Utah. This report will highlight the natural and social resources present in the county, detail specific concerns, and be used to aid in resource planning and target conservation assistance needs. This document is dynamic and will be updated as additional information is available through a multi-agency partnership effort. The general observations and summaries are listed first, followed by the specific resource inventories.

Economic Significance Of Recreational Uses Of National Parks And Other Public Lands, Dr. Daniel J. Stynes, National Park Service, U.S. Department Of The Interior

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

This paper reviews concepts and methods for estimating the economic significance of recreational uses of public lands and reports estimates of recreation values and economic impacts from recent studies. Aimed primarily at non-economists, the review clarifies the distinction between valuation and impact studies, defines key concepts, summarizes the most accessible approaches, and discusses conceptual and practical issues related to choosing among available methods and interpreting and applying the results. Terms that may be unfamiliar to the reader are highlighted in bold face and defined in a glossary at the end of the paper.

Flaws In Orr’S Laws (And The Paradigm That Produced Them): An Abbreviated Response, Nicole Haynes Mccoy, Sheldon Atwood

Behavioral Education for Human, Animal, Vegetation, and Ecosystem Management (BEHAVE)

Conservation of biological diversity is often hampered by ignorance and short-sightedness. Yet knowledge is not enough; biology illuminates ecological relationships, but it alone cannot conserve ecosystems. Therefore, we agree that there is no higher priority for conservation biologists than to improve their understanding of economics (Orr 2004, Law 1). Unfortunately, from many of his comments and the tenor of subsequent responses (Hayes 2004; Vitek 2004; Lovejoy 2004), it is evident that economics and, more important, parallels between ecology and economics are misunderstood, implying the two disciplines are more different than they are and that knowledge of economics is primarily needed …

Particle Size, Caco3, Chemical, Magnetic, And Age Data From Surficial Deposits In And Around Canyonlands National Park, Utah, Harland Goldstein, Richard Reynolds, Marith Reheis, James Yount, Paul Lamothe, Helen Roberts, John Mcgeehin

Canyonlands Research Bibliography

No abstract provided.

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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.