Atmospheric Sciences Commons^™

Low Cost Magnetometer Calibration And Distributed Simultaneous Multipoint Ionospheric Measurements From A Sounding Rocket Platform, Joshua W. Milford

Doctoral Dissertations and Master's Theses

Low-cost and low-size-weight-and-power (SWaP) magnetometers can provide greater accessibility for distributed simultaneous measurements in the ionosphere, either onboard sounding rockets or on CubeSats. The Space and Atmospheric Instrumentation Laboratory (SAIL) at Embry-Riddle Aeronautical University has launched a multitude of sounding rockets in recent history: one night-time mid-latitude rocket from Wallops Flight Facility in August 2022 and three mid-latitude rockets from White Sands Missile Range during the October 2023 annular solar eclipse. All rockets had a comprehensive suite of instruments for electrodynamics and neutral dynamics measurements. Among this suite was one science-grade three-axis fluxgate magnetometer (Billingsley TFM65VQS / TFM100G2) and up …

Initiation Criteria For The Onset Of Geomagnetic Substorms Based On Auroral Observations And Electrojet Current Signatures, Mayowa Michael Kayode-Adeoye

<strong> Theses and Dissertations </strong>

In recent years, several substorm onset criteria have been developed, either from auroral observations (many authors) or from auroral electrojet properties such as those described by (Forsyth et al., 2015; Maimaiti et al., 2019; Newell & Gjerloev, 2011; Partamies et al., 2011) The different criteria are being investigated using a low order physics model of the magnetosphere called WINDMI (Spencer et al., 2009) and inferences are being made in line with the WINDMI model. The model variables will be compared with the criteria for substorm onset proposed by examining the SML index.

The WINDMI model uses solar wind and IMF …

Investigation Of The Flow Field In The Jack Rabbit Ii Mock Urban Environment Field Tests Using A 1:50 Scale Wind Tunnel Model, Paulo Victor De Freitas Lopes

Graduate Theses and Dissertations

Accidental release of toxic chemicals can put workers and nearby populations at significant risk. Consequence assessment of accidents in urban environments is of particular interest. Urban geometries create wind channels between buildings, along with particularly dangerous areas downwind of buildings, where near-stagnant flow is present. Furthermore, recirculation zones can be formed between buildings, trapping high concentrations of toxic gases at ground level, particularly for denser-than-air gases. In 2015, the Department of Homeland Security conducted the Jack Rabbit II Field Test (JR-II) at Dugway Proving Ground, UT. During JR-II, chlorine was released at the center of a Mock Urban Environment (MUE) …

Characteristics Of Refractivity And Sea State In The Marine Atmospheric Surface Layer And Their Influence On X-Band Propagation, Douglas Matthew Pastore

Electronic Theses and Dissertations

Predictions of environmental conditions within the marine atmospheric surface layer (MASL) are important to X-band radar system performance. Anomalous propagation occurs in conditions of non-standard atmospheric refractivity, driven by the virtually permanent presence of evaporation ducts (ED) in marine environments. Evaporation ducts are commonly characterized by the evaporation duct height (EDH), evaporation duct strength, and the gradients below the EDH, known as the evaporation duct curvature. Refractivity, and subsequent features, are estimated in the MASL primarily using four methods: in-situ measurements, numerical weather and surface layer modeling, boundary layer theory, and inversion methods.

The existing refractivity estimation techniques often assume …

A Comparative Study Of Vinti-Based Orbit Propagation And Estimation For Cubesats In Very Low Earth Orbits, Ethan Michael Senecal

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years, there has been a growing interest in CubeSats and very low Earth orbit (VLEO) space missions. Mission SeaLion, a collaborative CubeSat mission between Old Dominion University, the U.S. Coast Guard Academy, and U.S. Air Force Institute of Technology, planned to launch a 3U CubeSat into VLEO. The VLEO mission is a particularly challenging environment for navigation and orbit propagation because drag introduces a significant perturbation for orbit models such as SGP4. Additionally, mission requirements left no capacity for attitude determination or control, further reducing knowledge of drag behavior of the satellite in flight. This deficiency is a …

Effect Of Morphology And An Upstream Tall Building On A Street Canyon Flow, Haoran Du

Electronic Thesis and Dissertation Repository

The effects of the morphological model and the existence of an upstream tall building on the turbulent street canyon flow and the overlying boundary layer are investigated in a wind tunnel, using Stereoscopic Particle Image Velocimetry (S-PIV) measurements. The velocity variances, Reynolds shear stress, and turbulent kinetic energy are found to be larger than in a similar idealized street canyon model. Increasing building height results in a decrease in vertical mass fluxes across the opening of the canyon, at least in the canyon portion directly downstream of the building. The interaction between the large-scale structures in the overlying boundary layer …

Probing The Structure Of Water On Surfaces: From Water Absorption To Ice Nucleation, Jiarun Zhou

All Dissertations

Water, essential for all life forms, is the most abundant, simple, yet mysterious molecule in the world. This molecule, consisting of only three atoms, behaves in unexpectedly different ways with the change of environment. In the past, studies of water under different conditions (temperature, pressure, on the surfaces, with confinement) have been conducted using experimental and computational methods. However, the influence of a given environment on water properties is yet to be fully understood. This dissertation studies water at complex interfaces (surfaces with various chemistry and physics properties) in both the liquid and crystalline states. Various heterogeneous systems used to …

Stratospheric Glider Measurements Of Atmospheric Parameters, Anisa Haghighi

Theses and Dissertations--Mechanical Engineering

In June 2021 a series of high altitude flights were conducted in Spaceport America, NM, using a balloon launched Uncrewed Aircraft System (UAS) to assess its capability to conduct measurements of various atmospheric properties and study turbulence in the troposphere and lower stratosphere. This UAS descends using an automated flight trajectory. The instruments aboard included a NASA-developed infrasonic microphone to evaluate its remote turbulence detection capabilities and a five-hole probe capable of measuring the in situ wind vector. Also on board were temperature, humidity and wind profile sensors. This document focuses on the atmospheric properties measured at high altitudes, the …

Unmanned Aircraft Systems For Precision Meteorology: An Analysis Of Gnss Position Measurement Error And Embedded Sensor Development, Karla S. Ladino

Theses and Dissertations--Biosystems and Agricultural Engineering

The overarching objective of this research was to enhance our comprehension of the three-dimensional precision of meteorological measurements obtained using small unmanned aircraft systems (UAS). Two complimentary experiments were conducted to achieve this objective.

The first experiment entailed the development and implementation of a system to determine the global navigation satellite system (GNSS) position accuracy on a UAS platform. This system was utilized to assess the static and dynamic accuracy of L1 and L1/L2 GNSS receivers in real-time kinematic (RTK) and non-RTK fix modes. Adjusted two-sample t-tests revealed significant differences in horizontal and vertical error between RTK and non-RTK receivers …

Identifying Particulate Matter Spatial Variation In The El Paso Del Norte Region Using Land-Use Regression Modeling And Data Obtained From A Network Of Low-Cost Sensors, Leonardo Demetrio Vazquez-Raygoza

Open Access Theses & Dissertations

The emergence and rise in popularity of low-cost sensors for atmospheric observation aresetting a new precedent in identifying emission hotspots and providing high-resolution spatial and temporal data. Furthermore, low-cost sensors are becoming popular among institutions and the public, allowing community scientists to become more involved in air quality monitoring. However, concerns about the accuracy and precision of low-cost sensors have been questioned. Most recent research has focused on the utility of real-time monitoring and calibration requirements for these sensors. A low-cost monitoring project has deployed sensors in the El Paso del Norte region in low and high annual average daily …

X-Band Phased-Array Weather-Radar Polarimetry Testbed, William Heberling Iv

Doctoral Dissertations

Phased-array weather radar have potential to replace reflector dish radar in major weather radar networks such as NEXRAD, providing faster update times and greater scan flexibility. However, the use of electronic scanning introduces polarization errors on weather radar measurables, requiring polarimetric bias calibration. The sources of polarimetric bias have been described theoretically, but experimental verification is still limited. Additionally, no standard method of calibration for polarimetric bias exists for phased-arrays. Therefore, the University of Massachusetts Amherst (UMass) presents a fully operational X-Band phased-array weather radar polarimetric testbed. The testbed evaluates the calibration of a planar dual-polarization X-band phased-array radar through …

Impact Of Climate Oscillations/Indices On Hydrological Variables In The Mississippi River Valley Alluvial Aquifer., Meena Raju

Theses and Dissertations

The Mississippi River Valley Alluvial Aquifer (MRVAA) is one of the most productive agricultural regions in the United States. The main objectives of this research are to identify long term trends and change points in hydrological variables (streamflow and rainfall), to assess the relationship between hydrological variables, and to evaluate the influence of global climate indices on hydrological variables. Non-parametric tests, MMK and Pettitt’s tests were used to analyze trend and change points. PCC and Streamflow elasticity analysis were used to analyze the relationship between streamflow and rainfall and the sensitivity of streamflow to rainfall changes. PCC and MLR analysis …

Global Sporadic-E Climatological Analysis Using Gps Radio Occultation And Ionosonde Data, Travis J. Hodos

Theses and Dissertations

A climatology of sporadic-E (Es) derived from a combined data set of GPS radio occultation (GPS-RO) and ground-based ionosonde soundings is presented for the period from September 2006 to February 2019. The ionosonde soundings were measured using the Lowell Digisonde International (LDI) Global Ionosphere Radio Observatory (GIRO) network consisting of 65 sites and 13,141,060 total soundings. The GPS-RO observations were taken aboard the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites and processed using two binary Es detection algorithms, totaling 9,072,922 occultations. The first algorithm is an S4 amplitude threshold calibrated to the occurrence of any blanketing Es …

Feasibility Of Fireball Trail Detection Using Ground-Based Gps Receivers, Ian R. Moffett

Theses and Dissertations

The feasibility of using GPS data to detect fireballs is analyzed by first modeling the fireball’s trail diffusion and plasma chemistry to get a resulting ion density profile of the trail over time. The signal perturbation caused by the fireball trail is simulated for a ground receiver using an analytic solution for diffraction from a Gaussian lens. Five cases were modeled with varying initial peak ion densities and altitudes taken from fireball and reentry vehicle data. This paper shows that it is feasible to detect a fireball trail using GPS if the fireball has a sufficiently high initial ion density, …

Physical Investigation Of Downburst Winds And Applicability To Full Scale Events, Federico Canepa

Electronic Thesis and Dissertation Repository

Thunderstorm winds, i.e. downbursts, are cold descending currents originating from cumulonimbus clouds which, upon the impingement on the ground, spread radially with high intensities. The downdraft phase of the storm and the subsequent radial outflow that is formed can cause major issues for aviation and immense damages to ground-mounted structures. Thunderstorm winds present characteristics completely different from the stationary Gaussian synoptic winds, which largely affect the mid-latitude areas of the globe in the form of extra-tropical cyclones. Downbursts are very localized winds in both space and time. It follows that their statistical investigation, by means of classical full scale anemometric …

Data Fusion And Synergy Of Active And Passive Remote Sensing; An Application For Freeze Thaw Detections, Zahra Sharifnezhadazizi

Dissertations and Theses

There has been a recent evolvement in the field of remote sensing after increase of number satellites and sensors data which could be fused to produce new data and products. These efforts are mainly focused on using of simultaneous observations from different platforms with different spatial and temporal resolutions. The research dissertation aims to enhance the synergy use of active and passive microwave observations and examine the results in detection land freeze and thaw (FT) predictions. Freeze thaw cycles particularly in high-latitude regions have a crucial role in many applications such as agriculture, biogeochemical transitions, hydrology and ecosystem studies. The …

Understanding The Relationship Between Urban Areas And The Boundary Layer Using Remote Sensing Methods, Gabriel A. Rios

Dissertations and Theses

The atmospheric boundary layer is crucial to the exchange in energy between the Earth's surface and the atmosphere. Within this layer, the majority of human activities are carried out, which makes understanding the boundary layer especially important for many of our interests. A key component of this energy exchange is found at the surface, was surface properties are the interface through which momentum, heat, moisture, and other fluxes are transferred between media. Not only does the surface act as an interface, but as an actor that influences the exchange efficiency and rates. This concept is the crux of atmospheric boundary …

Ionospheric F-Layer Dipole Flute Instability Effects On Electromagnetic Scattering In A Magnetohydrodynamic Plasma, Andrew J. Knisely

Theses and Dissertations

The ionosphere has significant impact on radio frequency (RF) applications such as satellites, over-the-horizon radar, and commercial communication systems. The dynamic processes effecting the behavior of the ionic content leads to a variety of instabilities that adversely affect the quality of RF signals. In the F-layer ionosphere, flute instability persists, appearing as two radial regions of high and low density perturbations elongated along the earth's geomagnetic field lines. The sizes of flute structures are comparable to the wavelengths in the high frequency spectrum. The objective is to characterize the high frequency scattering of an incident field by developing a 3D …

Do Secondary Cyclones Increase The Category Scale Of Atmospheric Rivers?, Edgar Sanchez Fausto

University Honors Theses

Atmospheric rivers (ARs) play a crucial role in delivering precipitation worldwide. This makes them an important phenomenon for water resource specialists to study. One such interest is to understand what mechanisms make ARs produce significant rainfall and associated hazards such as flooding. One possible mechanism is that AR duration or intensity may increase when it interacts with a secondary cyclone, either of which can increase the AR category scale. The purpose of this study is to determine whether AR and secondary cyclone interactions increase the category scale ARs. Out of 52 AR events analyzed, 32 events contained at least one …

Adaptive-Optimal Control Of Spacecraft Near Asteroids, Madhur Tiwari

Doctoral Dissertations and Master's Theses

Spacecraft dynamics and control in the vicinity of an asteroid is a challenging and exciting problem. Currently, trajectory tracking near asteroid requires extensive knowledge about the asteroid and constant human intervention to successfully plan and execute proximity operation. This work aims to reduce human dependency of these missions from a guidance and controls perspective. In this work, adaptive control and model predictive control are implemented to generating and tracking obstacle avoidance trajectories in asteroid’s vicinity.

Specifically, direct adaptive control derived from simple adaptive control is designed with e modification to track user-generated trajectories in the presence of unknown system and …

A New Method For Estimating The Physical Characteristics Of Martian Dust Devils, Shelly Cahoon Mann

Mechanical & Aerospace Engineering Theses & Dissertations

Critical to the future exploration of Mars is having a detailed understanding of the atmospheric environment and its potential dangers. The dust devil is one of these potential dangers. The transport of dust through saltation is believed to be the driving mechanism responsible for Martian weather patterns. The two primary mechanisms for dust transport are dust storms and dust devils. Dust devils on Mars are a frequent occurrence with one in five so called giant dust devils being large enough to leave scars on the surface that are visible from space. Due to the thin atmosphere, winds of 60 mph …

Optical And Physicochemical Properties Of Atmospherically Processed Brown Carbon Using Novel First-Principle Instrumentation, Benjamin Sumlin

McKelvey School of Engineering Theses & Dissertations

Atmospheric processing of brown carbon (BrC) – a class of spherical, internally-mixed, light-absorbing organic aerosol – emitted from smoldering biomass combustion is an understudied phenomenon with implications for climate science, air quality models, and satellite retrieval algorithms. BrC aerosols have received significant attention as a strong contributor to atmospheric light absorption in the shorter visible wavelengths and a driver of UV photochemistry. Their complex refractive indices (m=n+ik), size distributions, and carbon oxidation states dictate their optical properties, atmospheric residence times, and chemical interactions, respectively. There is currently a gap in our understanding of these fundamental particle properties and their evolution …

Developing A Machine Learning Framework For Upwind Surveyed Regions, Witenberg Santiago Rodrigues Souza

Graduate Research Theses & Dissertations

Every year, the Oil & Gas industry loses $2B dollars due to fugitive natural gas leaks. Identifying the source of a leak is a complex challenge, especially in suburban areas where gas leakage may be mixed with other sources. Besides the multitude of possible locations for a leak in an urban area, surveying an entire city may take considerable time and funds depending on the chosen method. This work proposes a framework based on unmanned areal vehicles (UAV) to survey a region for gas leaks. To accomplish this goal, we rely on the concept of a Upwind Survey Region (USR). …

On The Improvements Of Boundary-Layer Representation For High Resolution Weather Forecasting In Costal-Urban Environments, David Melecio-Vazquez

Dissertations and Theses

As large urban centers around the world become more densely populated, the global conversion from natural to man-made land surfaces will only increase. These land-use changes affect the urban surface energy budget which in turn changes the structure of the planetary boundary layer (PBL) above. With current high-performance computing systems, meteorological and built environment information can be better utilized to quantify the anthropogenic effects of these modifications. Although these systems have improved forecasting near-surface weather conditions, a comprehensive approach to represent urban impacts on the PBL is still limited. Improved PBL representation can lead to better weather and climate forecasts, …

Strategies For Reducing Greenhouse Gases From Liquid Dairy Manure, Vera Sokolov

Theses and Dissertations (Comprehensive)

Livestock production, including the storage, handling, and spreading of manure, are among the largest contributors to greenhouse gas emissions from the agricultural sector. Liquid dairy manure storages are hot spots of methane (CH₄), nitrous oxide (N₂O) and ammonia (NH₃). Both CH₄ and N₂O are greenhouse gases (GHG) which contribute to global warming, while NH₃ is an indirect source of N₂O and a risk to human health. Reducing emissions from manure storages is important not only for protection of environment and humans, but also for conserving the nutrients in …

The Aging And Impacts Of Atmospheric Soot: Closing The Gap Between Experiments And Models, Ogochukwu Yvonne Enekwizu

Dissertations

The main goal of this dissertation is to generate data and parameterizations to accurately represent soot aerosols in atmospheric models. Soot from incomplete combustion of fossil fuels and biomass burning is a major air pollutant and a significant contributor to climate warming. The environmental impacts of soot are strongly dependent on the particle morphology and mixing state, which evolve continuously during atmospheric transport via a process known as aging. To make predictions of soot impacts on the environment, most atmospheric models adopt simplifications of particle structure and mixing state, which lead to substantial uncertainties. Using an experimentally constrained modeling approach, …

Accumulation Of Polar Vorticity On Giant Planets: Towards A Three-Dimensional Theory, Shawn R. Brueshaber

Dissertations

My research investigates the polar atmospheric dynamics of the giant planets: Jupiter and Saturn (gas giants), and Uranus and Neptune (ice giants). I conduct my research modifying and applying the Explicit Planetary Isentropic Coordinate global circulation code to model the polar regions of the four giant planets.

The motivation behind my research is to uncover the reason why giant planet polar atmospheric dynamics differ. Jupiter features multiple circumpolar cyclones arranged in geometrical configurations, whereas Saturn features a single pole-centered cyclone. Uranus and Neptune also appear to have single pole-centered cyclones, albeit, larger than those on Saturn. …

Development Of Novel Instrumentation And Methods To Investigate The Composition And Phase Partitioning Of Semivolatile And Intermediately Volatile Organic Compounds In Atmospheric Organic Aerosol, Claire Fortenberry

McKelvey School of Engineering Theses & Dissertations

Atmospheric particulate matter (PM) is ubiquitous in both indoor and outdoor air and is generally detrimental to human health. PM composed of particles with aerodynamic diameters less than 2.5 um (PM2.5) are related to adverse health outcomes including heart disease and respiratory disease. Fundamentally, particle physical properties such as size and hygroscopicity are dictated by chemical composition, which can be highly complex, particularly for organic aerosol (OA). In both outdoor and indoor air, OA is composed substantially of intermediately volatile and semivolatile organic compounds (I/SVOCs), which exist in both gas and particle phases under typical atmospheric conditions. The distribution of …

Detection Of Reconnection Signatures In Solar Flares, Taylor R. Whitney

Theses and Dissertations

Solar flare forecasting is limited by the current understanding of mechanisms that govern magnetic reconnection, the main physical phenomenon associated with these events. As a result, forecasting relies mainly on climatological correlations to historical events rather than the underlying physics principles. Solar physics models place the neutral point of the reconnection event in the solar corona. Correspondingly, studies of photospheric magnetic fields indicate changes during solar flares -- particularly in relation to the field helicity -- on the solar surface as a result of the associated magnetic reconnection. This study utilizes data from the Solar Dynamics Observatory (SDO) Helioseismic and …

Simulation Of Sporadic-E Parameters Using Phase Screen Method, Daniel W. Stambovsky

Theses and Dissertations

A phase screen simulation experiment is designed and implemented to model radio occultation through sporadic-E ionospheric disturbances between a GPS transmitter operating at the L1 frequency and a second receiving satellite in low earth orbit (LEO). Simulations were made to test the linear relationship between plasma intensity and scintillation S4 index both posited (Arras and Wickert, 2018) and contended (Gooch et al., 2020) in previous literature. Results brought into question both the linear relationship and the use of S4 as a whole and an alternate metric was sought.