Atmospheric Sciences Commons^™

Seasonal Propagation Characteristics Of Mstids Observed At High Latitudes Over Central Alaska Using The Poker Flat Incoherent Scatter Radar, Michael R. Negale, Michael J. Taylor, M. J. Nicolls, Sharon L. Vadas, Kim Nielsen, Craig J. Heinselman

Publications

Near‐continuous electron density measurements obtained over a ∼3 year period, 2010–2013, using the Poker Flat Incoherent Scatter Radar (PFISR) in central Alaska (69°N, 147°W) have been analyzed to quantify the properties of over 650 high‐latitude medium‐scale traveling ionospheric disturbances (MSTIDs). Our analysis focused on the altitude range 100–300 km encompassing the lower ionosphere/thermosphere and yielded first full seasonal day/night distributions of MSTIDs at high northern latitudes with mean values: horizontal wavelength 446 km, horizontal phase speed 187 m/s, and period 41 min. These year‐round measurements fill an important summertime gap in existing MSTID measurements revealing predominantly eastward wave propagation during …

Atmospheric Radiation And Tgfs: Unexplained Radiation In Our Skies, Adrian Gallegos

Honors College Research

There is a significant correlation between atmospheric electrification via thunderstorms and the occurrence of large emissions of x-ray and gamma ray radiation known as Terrestrial Gamma Ray Flashes (TGFs). Some physical phenomenon may be explained by either the RREA or Thermal Runaway models, but the scientific community as a whole is still largely at work on the theoretical frameworks.

Effects Of Magnetic Fields On An Unsteady Mixed Convective Boundary Layer Flow Of An Electrically Conducting Fluid With Temperature Dependent Properties, Raymond Kitengeso, Eunice Mureithi, Makungu James, John Mango

Tanzania Journal of Science

A mixed convective boundary layer flow of an electrically conducting fluid with temperature dependent properties over an inclined plate is investigated. The magnetohydrodynamic boundary layer governing equations are derived by using Boussinesq and boundary layer approximations. The equations are transformed to similarity form using a similarity transformation variable and the resulting boundary value problem is solved numerically. The effects of magnetic fields, unsteadiness, mixed convection and variable fluid properties on velocity and temperature in the boundary layer are analysed. The effects of pertinent parameters on skin friction and heat transfer are also analysed

Error Analysis Of Multi-Needle Langmuir Probe Measurement Technique, Aroh Barjatya, William Merritt

Publications

Multi-needle Langmuir probe is a fairly new instrument technique that has been flown on several recent sounding rockets and is slated to fly on a subset of QB50 CubeSat constellation. This paper takes a fundamental look into the data analysis procedures used for this instrument to derive absolute electron density. Our calculations suggest that while the technique remains promising, the current data analysis procedures could easily result in errors of 50% or more. We present a simple data analysis adjustment that can reduce errors by at least a factor of five in typical operation.

Impacts Of Sub-Auroral Polarization Streams On High Frequency Operations As A Function Of Modeled Particle Energy Flux, Nathan D. Smith

Theses and Dissertations

Space weather events can cause irregularities within the ionosphere; in particular, this research examines sub-auroral polarization streams (SAPS), as their accompanying irregularities and effects can degrade high-frequency (HF) signal propagation. It is known that the strongest westerly current drifts delineating SAPS are associated with a deep ionospheric trough, which in turn contaminates HF data with clutter from the non-standard ionosphere. Having a methodology to track and identify these occurrences on current computational architecture would provide operators enhanced situational awareness in knowing to expect degradation in HF processes. This study has discovered a weak, yet significant, exponentially decaying correlation between maximum …

Ceilometer Measurements From The University Of Western Ontario Of Smoke From The Extraordinary Fires Of 2017 In Western Canada, Achini J K Abayakoon Ms.

Western Research Forum

Background:

The summer of 2017 saw many fires in Western Canada. Smoke from these fires was transported by winds over to London and was measured using a Lufft CHM15k ceilometer which was installed at the Cronyn Observatory of The University of Western Ontario.

Methods:

The cloud base height can be calculated by the time taken for the backscatter signal to reach the transmitter while the backscatter effects can be used to determine the atmospheric structure using the principle of light detection and ranging (LiDAR).

Results:

Smoke particle concentrations over London, Ontario were observed within 72 hours of the fires taking …

Unexpected Occurrence Of Mesospheric Frontal Gravity Wave Events Over South Pole (90°S), Pierre-Dominique Pautet, Michael J. Taylor, J. B. Snively, Christina Solorio

Publications

Since 2010, Utah State University has operated an infrared Advanced Mesospheric Temperature Mapper at the Amundsen–Scott South Pole station to investigate the upper atmosphere dynamics and temperature deep within the vortex. A surprising number of “frontal” gravity wave events (86) were recorded in the mesospheric OH(3,1) band intensity and rotational temperature images (typical altitude of ~87 km) during four austral winters (2012–2015). These events are gravity waves (GWs) characterized by a sharp leading wave front followed by a quasi-monochromatic wave train that grows with time. A particular subset of frontal gravity wave events has been identified in the past (Dewan …

Mid-Latitude Climatologies Of Mesospheric Temperature And Geophysical Temperature Variability Determined With The Rayleigh-Scatter Lidar At Alo-Usu, Joshua P. Herron, Vincent B. Wickwar

All Physics Faculty Publications

From 1993-2004, 839 nights were observed with the Rayleigh-scatter lidar at Utah State University’s Atmospheric Lidar Observatory. They were reduced to obtain nighttime mesospheric temperatures between 45 and ~90 km, which were then combined to derive composite annual climatologies of mid-latitude temperatures and geophysical temperature variability. At 45 km, near the stratopause, there is a ~250 K temperature minimum in mid-winter and a 273 K maximum in mid-May. The variability behaves oppositely, being 7-10 K in winter and 2.5 K in summer. At 85 km, there is a 215 K temperature maximum at the end of December and a 170 …

Data Supporting The Paper "Influence Of Microphysical Variability On Stochastic Condensation In A Turbulent Laboratory Cloud", N. Desai, K. K. Chandrakar, K. Chang, Will Cantrell, Raymond Shaw

Department of Physics Publications

No abstract provided.

Climate Modeling, Outgoing Longwave Radiation, And Tropical Cyclone Forecasting, Thomas Rechtman

Honors Undergraduate Theses

Climate modeling and tropical cyclone forecasting are two significant is- sues that are continuously being improved upon for more accurate weather forecasting and preparedness. In this thesis, we have studied three climate models and formulated a new model with a view to determine the outgoing longwave radiation (OLR) budget at the top of the atmosphere (TOA) as ob- served by the National Oceanic and Atmospheric Administration’s (NOAA) satellite based Advanced Very High Resolution Radiometer (AVHRR). In 2006, Karnauskas proposed the African meridional OLR as an Atlantic hur- ricane predictor, the relation was further proven in 2016 by Karnauskas and Li …

Recommissioning Reddi: Reviving A Doppler Asymmetric Spatial Heterodyne Spectrometer For Observing Thermospheric Winds, Robert Kallio

Doctoral Dissertations and Master's Theses

The REd-line DASH Demonstration Instrument (REDDI) was designed to prove that a Doppler Asymmetric Spatial Heterodyne (DASH) spectrometer could be used to accurately measure thermospheric winds by observing the Doppler shift of the 630nm emission of oxygen in the thermosphere. In 2015, we began a project to redesign the input optics of REDDI to repurpose the instrument from a demonstration unit to a long duration instrument. Integration of REDDI into the INSpIRe (Investigating Near-Space Interaction Regions) trailer at Embry-Riddle Aeronautical University (ERAU), Daytona Beach, began in 2016 with assembly of the new input optics in 2017. REDDI and INSpIRe will …

Comparison Of Various Mean Field Formulations For Retrieving Refractive Indices Of Aerosol Particles Containing Inclusions, Kristin S. Dooley, Jessica Deyoung

Journal of the Arkansas Academy of Science

Application of effective medium approximation (EMA) methods to two-component systems are presented. Systems studied are composed of water, sulfate, soot, and dust as these are commonly encountered atmospheric aerosol components. Atmospheric models often employ EMAs to include internally mixed aerosols without the computational burden of exact theory. In the current work, several types of mixing rules (Maxwell-Garnet, Bruggeman, and coherent potential approximation) have been applied to various two-component internally mixed particles at 550 nm using volume fractions of the minor component below 0.1. As expected, results show that the formulations tested produce very similar effective refractive indices indicating that electric …

Evaluating The Effectiveness Of Current Atmospheric Refraction Models In Predicting Sunrise And Sunset Times, Teresa Wilson

Dissertations, Master's Theses and Master's Reports

The standard value for atmospheric refraction on the horizon of 34', used in all publicly available sunrise and sunset calculators, is found to be inadequate. The assumptions behind atmospheric models that predict this value fail to account for real meteorological conditions. The result is an uncertainty of one to five minutes in sunrise and sunset predictions at mid-latitudes (0° - 55° N/S). A sunrise/set calculator that interchanges the refraction component by varying the refraction model was developed. Two atmospheric refraction models of increasing complexity were tested along with the standard value. The predictions were compared with data sets of observed …

Analysis Of The Red And Green Optical Absorption Spectrum Of Gas Phase Ammonia, Nikolai F. Zobov, Phillip A. Coles, Roman I. Ovsyannikov, Aleksandra A. Kyuberis, Robert J. Hargreaves, Peter F. Bernath, Jonathan Tennyson, Sergei N. Yurchenko, Oleg L. Polyansky

Chemistry & Biochemistry Faculty Publications

Room temperature NH₃ absorption spectra recorded at the Kitt Peak National Solar Observatory in 1980 are analyzed. The spectra cover two regions in the visible: 15,200 - 15,700 cm^-1 and 17,950 - 18,250 cm^-1. These high overtone rotation-vibration spectra are analyzed using both combination differences and variational line lists. Two variational line lists were computed using the TROVE nuclear motion program: one is based on an ab initio potential energy surface (PES) while the other used a semi-empirical PES. Ab initio dipole moment surfaces are used in both cases. 95 energy levels with J = 1 …

Improved Ballistic Wind Prediction Using Projectile Tracking Data, William Arthur Kenney

Computational Modeling & Simulation Engineering Theses & Dissertations

The United States Air Force AC-130 gunships have been in operation since the Vietnam War and have seen frequent use during recent conflicts. They are able to employ gun weapon systems from above a target in a way that maximizes possible time on target. When firing, the gun operators must deal with miss distances caused by winds acting on the projectile in flight. Operators currently perform a “tweak” to predict a ballistic wind affecting fired rounds which is then used in the fire-control to correct for the real winds and bring shots onto target. This correction, a single-point wind prediction, …

Opal Cubesat Data Analysis Model, Kenneth Zia, Ludger Scherliess, Michael J. Taylor

Physics Student Research

Understanding the Earth’s lower thermosphere (altitude range 9 km -140km) is of growing interest for many areas of research within the space weather community. The NSF sponsored OPAL (Optical Profiling of the Atmospheric Limb) mission is designed to measure temperature profile by observing the integrated line of sight of the day-time O2 A-band (~760nm) emissions on the limb. The OPAL instrument has an altitude resolution of 1.03km from 80-160km flown on a 3U CubeSat, and is expected to be launched from the ISS (International Space Station) (~400km altitude). We have developed a model of OPAL’s position and attitude of its …

Solar Wind-Magnetosphere Coupling: A Global Perspective Of Reconnection In The Magnetotail, Miles Thomas Bengtson

Doctoral Dissertations and Master's Theses

We present a case study of the 25 December 2015 substorm which occurred between 08:15 and 08:45 Universal Time. During this interval, fast particle flows and field geometry consistent with magnetic reconnection were detected in the mid-tail region. An ejected plasmoid was observed by the lunar-orbiting Acceleration, Reconnection, Turbulence and Electrodynamics of Moon’s Interaction with the Sun (ARTEMIS) probes and corresponding dipolarization signature was observed by the Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecraft earthward of the reconnection site, which was determined to be approximately -33 RE. Ground signatures indicative of substorm activity were also observed …

Design And Characterization Of A Time-Of-Flight Mass Spectrometer For Composition Measurements In The Upper Atmosphere, E. Addison Everett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The mesosphere/lower thermosphere (MLT) is perhaps the least understood region of Earth's atmosphere. Too high for balloons and winged aircraft, yet too low for satellites, direct access to the MLT to make in-situ measurements is via high-speed sounding rockets for brief periods of at most a few minutes. Mass spectrometers have previously been used to make composition measurements in this region. But, mass spectrometry in the MLT is difficult, mainly due to the ambient pressures here and also the high speeds and short flight durations of sounding rocket missions. Time-of-flight mass spectrometers (TOF-MS) are capable of making fast, accurate measurements …

P16. Ralmo Rotational Raman Temperature Retrieval: First Steps Towards The Application Of Optimal Estimation Method (Oem), Shayamila N. Mahagammulla Gamage, Robert Sica, Alexander Haefele

Western Research Forum

Background:

Temperature is an important atmospheric parameter that plays an extensive role in the fields of atmospheric dynamics, climatology, meteorology, and chemistry. Light detection and ranging (lidar), is a remote sensing technology that can be used for atmospheric temperature profiling. A lidar transmits short laser pulses into the atmosphere and the light scattered by the particles in the atmosphere is collected and measured using a telescope. The atmospheric temperatures can be retrieved by analysing the Pure Rotational Raman (PRR) scatter measurements from the nitrogen and oxygen molecules in the atmosphere.

Methods:

In this study use the Optimal Estimation Method (OEM) …

Ozone Depletion, A Big Threat To Climate Change: What Can Be Done?, Sumera Aziz Ali, Savera Aziz Ali, Nadir Suhail

Community Health Sciences

Ozone in the stratosphere is very important as it acts as a safeguard for the earth and protects life from harmful ultraviolet radiations coming from the sun. Depletion of stratospheric ozone, resulting from atmospheric pollution has led to increased ultraviolet radiation at the earth’s surface as well as spectral shifts to the more biologically damaging shorter wavelengths. A decrease in the concentration of stratospheric ozone enhances the solar ultraviolet (UV) radiation, which is harmful to the growth of the plant and various other metabolic processes of the organisms and might cause changes in pigment concentrations, nucleic acids, and proteins. Multiple …

Studies Of Direct Solar Irradiance And Aerosol Optical Depth Using An Mfrsr And A Microtop Sunphotometer In The El Paso-Juarez Airshed, Arjun Aryal

Open Access Theses & Dissertations

The study of Solar Irradiance and Aerosol Optical Depth (AOD) plays an important role in understanding the regional and global climate distribution, and is also important in air pollution studies. In this work an MFRSR (Multi-Filter Rotating Shadowband Radiometer) and a Portable Microtop Sunphotometer were used to measure irradiances and to obtain optical depth values for the El Paso-Juarez Airshed. The Langley method applied on the MFRSR irradiance data was used to calculate the AOD values. The spatial distribution of AOD for this region was obtained using a Microtop Sunphotometer. The graphs were generated using GIS Shapefiles. In addition, the …

Influence Of Volcanic Eruptions On Tropical Hydroclimate During The Last Millennium, Christopher Colose

Legacy Theses & Dissertations (2009 - 2024)

Volcanic eruptions exert the most important radiative forcing on Earth’s climate during the pre-industrial interval of the last millennium. In this thesis, I investigate the role of volcanic eruptions in altering tropical climate, including temperature and rainfall. I primarily use forced transient simulations of the last millennium as a tool to explore how explosive volcanic events project onto the hydrologic cycle, as well as the imprint of water isotopologues (H216O, H218O) associated with rainfall. Attention is given to the South American continent specifically (in chapter 2), and to the entire tropics (in chapter 3).

New And Improved Infra-Red Absorption Cross Sections And Ace-Fts Retrievals Of Carbon Tetrachloride (Ccl4), Jeremy J. Harrison, Christopher D. Boone, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

Carbon tetrachloride (CCl₄) is one of the species regulated by the Montreal Protocol on account of its ability to deplete stratospheric ozone. As such, the inconsistency between observations of its abundance and estimated sources and sinks is an important problem requiring urgent attention (Carpenter et al., 2014) [5]. Satellite remote-sensing has a role to play, particularly limb sounders which can provide vertical profiles into the stratosphere and therefore validate stratospheric loss rates in atmospheric models. This work is in two parts. The first describes new and improved high-resolution infra-red absorption cross sections of carbon tetrachloride/dry synthetic air over …

The Hitran2016 Molecular Spectroscopic Database, I. E. Gordon, L. S. Rothman, C. Hill, R. V. Kochanov, Y. Tan, P. F. Bernath, M. Birk, V. Boudon, A. Campargue, K. V. Chance

Chemistry & Biochemistry Faculty Publications

This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional …

Dynamical Processes Of Gravity Waves Propagation And Dissipation, And Statistical Characteristics Of Their Momentum Flux In The Mesosphere And Lower Thermosphere, Bing Cao

Doctoral Dissertations and Master's Theses

The mesosphere and lower thermosphere (MLT) (⇠80–110 km) is dominated by abundant atmospheric waves, of which gravity waves are one of the least understood due to large varieties in wave characteristics as well as potential sources. Gravity waves play an important role in the atmosphere by influencing the thermal balance and helping to drive the global circulation. But due to their sub-grid scale, the effects of gravity waves in General Circulation Models (GCMs) are mostly parameterized. The investigations of gravity waves in this dissertation are from two perspectives: the dynamical processes of gravity wave propagation and dissipation in the MLT …

Gravity Wave And Turbulence Transport In The Mesopause Region, Yafang Guo

Doctoral Dissertations and Master's Theses

Vertical transport due to 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 operation since 2010. The upgrade of the lidar system in May 2014 resulted in great improvements of the signal levels, which enabled data acquisition of high temporal and vertical resolutions reaching 6 s and 25 m. Traditional data processing utilizes signals at lower resolutions, typically at 60 s and 500 m, …

A Laboratory Facility To Study Gas-Aerosol-Cloud Interactions In A Turbulent Environment: The Π Chamber, K. Chang, J. Bench, M. Brege, Will Cantrell, K. Chandrakar, David Ciochetto, Claudio Mazzoleni, Lynn Mazzoleni, Dennis Niedermeier, R. A. Shaw

Department of Physics Publications

A detailed understanding of interactions of aerosols, cloud droplets/ice crystals, and trace gases within the atmosphere is of prime importance for an accurate understanding of Earth’s weather and climate. One aspect that remains especially vexing is that clouds are ubiquitously turbulent, and therefore thermodynamic and compositional variables, such as water vapor supersaturation, fluctuate in space and time. With these problems in mind, a multiphase, turbulent reaction chamber—called the Π chamber because of the internal volume of 3.14 m³ with the cylindrical insert installed—has been developed. It is capable of pressures ranging from 1,000 to –60 hPa and can sustain …

Infrasound Propagation In Terrestrial Planetary Atmospheres, Lynsey B. Schroeder

Doctoral Dissertations and Master's Theses

Acoustic waves in the infrasonic frequency range, that is below 10 Hertz, have been observed to propagate to high altitudes in Earth's atmosphere. These waves have many sources, both natural and artificial, such as seismic events, convective storm systems, and nuclear explosions. Here, we seek to better understand the characteristics of atmospheric infrasound- below 0.1 Hz in particular- so as to improve the ability to detect their presence and sources. It is well-known that ambient attributes of an atmosphere, such as temperature, density, and composition, directly affect the propagation and growth of waves, and therefore it is likely that these …

On The Propagation Of Atmospheric Gravity Waves In A Non-Uniform Wind Field: Introducing A Modified Acoustic-Gravity Wave Equation, Ahmad Talaei

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

Atmospheric gravity waves play fundamental roles in a broad-range of dynamical processes extending throughout the Earth’s neutral atmosphere and ionosphere. In this paper, we present a modified form for the acoustic-gravity wave equation and its dispersion relationships for a compressible and non-stationary atmosphere in hydrostatic balance. Importantly, the solutions have been achieved without the use of the well-known Boussinesq approximation which have been used extensively in previous studies.

We utilize the complete set of governing equations for a compressible atmosphere with non-uniform airflows to determine an equation for vertical velocity of possible atmospheric waves. This intricate wave equation is simplified …

Searching For Troposphere-Mesosphere Connections Using The Alo-Usu Rayleigh-Scatter Lidar, David K. Moser, Vincent B. Wickwar, Joshua P. Herron

Posters

The paucity of whole-atmosphere data introduces significant challenges that hinder the study of atmospheric couplings. The mesosphere in particular is a low-information void between the lower and upper atmosphere, which may prevent us from a complete realization of vertical interactions. The Rayleighscatter lidar at Utah State University’s Atmospheric Lidar Observatory (ALO-USU; 41.74° N, 111.81° W), operated with little interruption from 1993 to 2004, providing a valuable temporal and spatial (45 – 90 km) resource in this realm. When studied alongside a multitude of other atmospheric data sources, possible unforeseen connections or insights may result. In this study, an adaptive fit …