Physical Sciences and Mathematics Commons^™

Hydroclimatic Forecasting In The Western United States Using Paleoclimate Reconstructions And Data-Driven Models, Christopher Allen Carrier

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis investigated climate variability and their associated hydrologic responses in the western United States. The western United States faces the problem of water scarcity, where the management and mitigation of available water supplies are further complicated by climate variability. Climate variability associated with the phases of oceanic-atmospheric oscillations has been shown to influence streamflow and precipitation, where predictive relationships have led to the possibility of producing long-range forecasts. Based on literature review, four oceanic-atmospheric oscillation indices were identified in having the most prominent influence over the western United States including the El Niño - Southern Oscillation (ENSO), Pacific Decadal …

Verification Of Global Assimilation Of Ionospheric Measurements Gauss Markov (Gaim-Gm) Model Forecast Accuracy, Paul H. Domm

Theses and Dissertations

GAIM-GM is an operational Kalman filter data assimilation model of the ionosphere that can assimilate data from GPS total electron content (TEC), ionosonde electron density profiles, and satellite based in situ electron densities. The Air Force Weather Agency (AFWA) uses GAIM-GM to specify and forecast the ionosphere. An in depth investigation into the accuracy of these forecasts has not been completed. GAIM-GM output obtained from four cases run from combinations of geomagnetic and solar activity was used to determine GAIM-GM forecast accuracy. Forecast accuracy was determined through the use of a skill score as well as other statistical tools to …

Assessment Of The Effects Of Plasma Bubbles On Gaim-Gm, Kenneth R. Fenton

Theses and Dissertations

Plasma bubbles are regions of depleted plasma density generated in the post-sunset equatorial region of the ionosphere. Bubbles significantly affect total electron count (TEC) and consequently alter communication and navigation capabilities. Here, the Global Assimilation of Ionospheric Measurements Gauss-Markov (GAIM-GM) model is studied in order to assess its capability to accurately model equatorial plasma bubbles. GAIM-GM uses the Ionospheric Forecast Model (IFM) as a background state modified through the application of a Kalman Filter to incorporate ionospheric observations such as Global Positioning System (GPS) total electron content (TEC) values. GPS TEC values representative of plasma bubble conditions are modeled and …

Effect Of Storm Enhanced Densities On Geo-Location Accuracy Over Conus, Lindon H. Steadman

Theses and Dissertations

Storm enhanced densities (SEDs) are ionospheric plasma enhancements that disrupt radio communications in the near-Earth space environment, degrading the Global Positioning System (GPS) and other key technologies. Accurate GPS/total electron content (TEC) correction maps produced by ionosphere models can mitigate degradations from SEDs. An artificial SED was created and ingested via slant TEC measurements into the Global Assimilation of Ionospheric Measurements Gauss-Markov Kalman Filter Model to determine how many ground GPS receivers are needed to produce reliable GPS/TEC correction maps over the continental United States during geomagnetic storming. It was found that 110 well-positioned GPS receivers produced the best overall …

Hyperspectral-Based Adaptive Matched Filter Detector Error As A Function Of Atmospheric Profile Estimation, Allan W. Yarbrough

Theses and Dissertations

Hyperspectral imagery is collected as radiance data. This data is a function of multiple variables: the radiation profile of the light source, the reflectance of the target, and the absorption and scattering profile of the medium through which the radiation travels as it reflects off the target and reaches the imager. Accurate target detection requires that the collected image matches as closely as possible the known "true" target in the classification database. Therefore, the effect of the radiation source and the atmosphere must be removed before detection is attempted. While the spectrum of solar light is relatively stable, the effect …

On The Variation Of Gravity Wave Activity Through The Solar Cycle At The South Pole, Ryan Matthew Agner

Doctoral Dissertations and Master's Theses

Atmospheric dynamics comprise of a multitude of phenomena from various sources that affect the entire climate of the globe. Some of these phenomena include Atmospheric Gravity Waves which are ubiquitous features around the planet. They are important mechanisms for the transport of momentum and energy from the lower atmosphere to the upper atmosphere. The sun is the ultimate source of energy for the earth and the primary driver of atmospheric dynamics. The 11-year solar cycle of the sun has had a noticeable effect on the overall climate of the earth in the past. More recent work has seen the diurnal …

The Effect Of An Offshore Wind Turbine Array On Circulation In An Idealized Coastal Ocean, Mahmoud Kamel

OES Theses and Dissertations

The effect of arrays of wind turbines on circulation in the coastal ocean is analyzed with a coastal numerical model applied to a shallow coastal area like the Mid Atlantic Bight (MAB). A simplified model domain is specified with a linearly deepening shelf along a straight coastline. The initial density structure is a quasi-two layer situation with a sharp thermocline. Wind stress in most of the cases is either upwelling or downwelling favorable with constant amplitude continuing after a smooth start. There are two cases where oscillating wind forcing is used. Simulations consider wind arrays having different widths, different locations …

Numerical Simulations Of Composition Changes In The High Latitude Thermosphere During Disturbed Conditions, Albert T. Russell

Electronic Thesis and Dissertation Repository

The closure of magnetospheric currents in the high latitude ionosphere makes the
high latitude thermosphere a very dynamic environment. The composition and dynamics
of this region become even more complex during geomagnetic disturbances
as the electric fields from the magnetosphere now have the ability to substantially
alter the winds and composition of this region. This complexity is especially apparent
in mass spectrometer observations of composition changes, with heavier gases
(N₂,O₂, andAr) showing substantial enhancements while lighter gases (He and O)
normally exhibit moderate to severe depletions. Quantifying the changes in atomic
and molecular oxygen can be …

Fabry-Perot Observations Of Midlatitude Neutral Winds And Atmospheric Gravity Wave Activity, Marjory Anne Katon

Doctoral Dissertations and Master's Theses

The mesosphere and lower thermosphere displays a wide range of dynamical phenomena resulting in a complex and variable regions. Governed primarily by fluid dynamics, the motion of the upper atmosphere is modulated by a number of atmospheric waves propagating upward from various sources in the lower atmosphere. Among these are atmospheric gravity waves which have been recognized as a major source of momentum and energy in the mesosphere and lower thermosphere as well as a major factor in the dynamic coupling between the troposphere and lower thermosphere. A Fabry-Perot interferometer possessed by the Space Physics Research Laboratory at the Embry-Riddle …

Wind Regimes In Complex Terrain Of The Great Valley Of Eastern Tennessee, Kevin Ray Birdwell

Doctoral Dissertations

This research was designed to provide an understanding of physical wind mechanisms within the complex terrain of the Great Valley of Eastern Tennessee to assess the impacts of regional air flow with regard to synoptic and mesoscale weather changes, wind direction shifts, and air quality. Meteorological data from 2008–2009 were analyzed from 13 meteorological sites along with associated upper level data. Up to 15 ancillary sites were used for reference. Two-step complete linkage and K-means cluster analyses, synoptic weather studies, and ambient meteorological comparisons were performed to generate hourly wind classifications. These wind regimes revealed seasonal variations of underlying physical …

A Preliminary Climatology Of Tropical Moisture Exports In The Southern Hemisphere, Alicia M. Bentley, Lance F. Bosart, Jason M. Cordeira

Atmospheric & Environmental Sciences

Heavy precipitation events in the midlatitudes can be supported by the poleward transport of tropical air masses within the warm sector of extratropical cyclones. Previous studies have established a climatology of the four preferred pathways of tropical moisture export (TME) events into the midlatitudes over the Northern Hemisphere (NH). The present study constructs a similar climatology of TME timing and frequency over the Southern Hemisphere (SH), highlighting three preferential regions for tropicalmidlatitude interaction. These regions correspond to the locations of the: (i) South Pacific convergence zone (Pacific Ocean pathway, PO), (ii) South Atlantic convergence zone (South American pathway, SA), and …

Searching For Melting-Induced Cold-Pool Circulations In An Oklahoma Winter Storm, Gabriel Susca-Lopata

Atmospheric & Environmental Sciences

This paper investigates the thermodynamic and dynamic impacts of melting precipitation through a case study of an Oklahoma winter storm. On 28 January 2005 a rain and snow event affected the state of Oklahoma. A combination of radiosonde data, wind profiler data, radar imagery and Oklahoma Mesonet surface data show that latent cooling from melting caused the surface temperatures to fall in western Oklahoma while evaporation caused surface cooling in central and eastern Oklahoma. The wind and surface pressure fields in western Oklahoma are analyzed along with radar data from Frederick Air Force Base, and some limited evidence for melting-driven …

Analysis Of Banding In 26-27 December 2010 East Coast Blizzard, Sara Ganetis

Atmospheric & Environmental Sciences

Blizzard conditions occurred in the New York City metropolitan area and portions of adjacent southern New England on 26-27 December 2010 in conjunction with a strong coastal cyclone. Parts of New Jersey received over 80 cm of snow while Long Island and coastal Connecticut observed wind gusts of over 30 ms-1. The heaviest snow was concentrated along a north-south oriented mesoscale snowband that extended from coastal New Jersey northward through the New York City metropolitan area. This mesoscale snowband, which remained quasi-stationary for approximately 12 h, was associated with strong low and mid-level frontogenetical forcing. In addition to the primary …

Event Discovery And Classification In Space-Time Series: A Case Study For Storms, Avinash Rude

Electronic Theses and Dissertations

Recent advancement in sensor technology has enabled the deployment of wireless sensors for surveillance and monitoring of phenomenon in diverse domains such as environment and health. Data generated by these sensors are typically high-dimensional and therefore difficult to analyze and comprehend. Additionally, high level phenomenon that humans commonly recognize, such as storms, fire, traffic jams are often complex and multivariate which individual univariate sensors are incapable of detecting. This thesis describes the Event Oriented approach, which addresses these challenges by providing a way to reduce dimensionality of space-time series and a way to integrate multivariate data over space and/or time …

Dynamics Of Equatorial Spread F Using Ground-Based Optical And Radar Measurements, Narayan P. Chapagain

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Earth's equatorial ionosphere most often shows the occurrence of large plasma density and velocity fluctuations with a broad range of scale sizes and amplitudes. These night time ionospheric irregularities in the F-region are commonly referred to as equatorial spread F (ESF) or plasma bubbles (EPBs). This dissertation focuses on analysis of ground-based optical and radar measurements to investigate the development and dynamics of ESF, which can significantly disrupt radio communication and GPS navigation systems. OI (630.0 nm) airglow image data were obtained by the Utah State University all-sky CCD camera, primarily during the equinox period, from three different longitudinal …

An Investigation Of Atmospheric Turbulence Probes With Ground Test Comparisons Of Probe Head Designs And Evaluation Of Suitability To Instrumented Aircraft, Charles F Lams

Masters Theses

A comparison of methods to determine the flow angle components of atmospheric velocity vectors is presented. The atmospheric turbulence probes used to measure behavior of the atmosphere use different methods to obtain this information and there is some confusion as to which method is best. Although the methods are all based upon potential flow theory, the details about how the atmospheric and flight parameters are measured makes a difference to the design of an atmospheric turbulence probe and carrier research aircraft. This paper presents the mathematical theory behind five methods of obtaining atmospheric flow angle measurements from a moving aircraft. …

Surface Morphology Implications On Langmuir Probe Measurements, Padmashri Suresh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Langmuir probes are extensively employed to study the plasmas in space and laboratory environments. Successful measurements require a comprehensive modeling of both the plasma environment and the probe conditions in the form of current collection models. In this thesis, the surface morphology implications on the probe current collection are investigated. This problem is applied and solved in the context of a CubeSat regime. The first problem that is investigated is the consequence of surface structural variability on the current measurements. A new model for dealing with non-uniformity of the probe surface structure is developed in this paper. This model is …

Design And Demonstration Of A Miniature Lidar System For Rover Applications, Benjamin Robinson

Electrical & Computer Engineering Theses & Dissertations

Public awareness of harmful human environmental effects such as global warming has increased greatly in recent years and researchers have increased their efforts in gaining more knowledge about the Earth's atmosphere. Natural and man-made processes pose threats lo the environment and human life, so knowledge of all atmospheric processes is necessary. Ozone and aerosols are important factors in many atmospheric processes and active remote sensing techniques provide a way lo analyze their quantity and distribution.

A compact ground-based lidar system for a robotic platform meant for atmospheric aerosol measurements was designed, tested, and evaluated. The system will eventually be deployed …

Analysis Of Plasma Bubble Signatures In The Ionosphere, Omar A. Nava

Theses and Dissertations

Plasma bubbles are large scale structures of depleted plasma density in Earth's ionosphere that disrupt radio and satellite communications, to include global navigation satellite systems. This study used the Ionospheric Forecast Model (IFM) to analyze affected look angles and total electron content (TEC) differences due to plasma bubbles of various sizes for 27 geophysical conditions consisting of different seasons and levels of solar and geomagnetic activity at 421 GPS ground stations worldwide. Overall, different geographic locations and plasma bubble configurations produced different affected look angle profiles. Bigger plasma bubbles, larger density depletion factors, higher levels of solar activity and the …

Passive Ranging Of Dynamic Rocket Plumes Using Infrared And Visible Oxygen Attenuation, Robert Anthony Vincent

Theses and Dissertations

Atmospheric oxygen absorption bands in observed spectra of boost phase missiles can be used to accurately estimate range from sensor to target. This work compares two oxygen absorption bands in the near-infrared (NIR) and visible (Vis) spectrum, centered at 762nm and 690 nm, to passively determine range. Spectra were observed from static tests of both surface-to-air missile simulators at 405m range and a full-scale solid rocket motor at 900m range. The NIR O₂ band provided range estimates accurate to within 3% for both tests, while the Vis O₂ band had range errors of 77% and 15 %, respectively. …

Aerosol Characterizaton In El Paso-Juarez Airshed Using Optical Methods, Angel E. Esparza

Open Access Theses & Dissertations

The assessment and characterization of atmospheric aerosols and their optical properties are of great significance for several applications such as air pollution studies, atmospheric visibility, remote sensing of the atmosphere, and impacts on climate change. Decades ago, the interest in atmospheric aerosols was primarily for visibility impairment problems; however, recently interest has intensified with efforts to quantify the optical properties of aerosols, especially because of the uncertainties surrounding the role of aerosols in climate change. The main objective of the optical characterization of aerosols is to understand their properties. These properties are determined by the aerosols' chemical composition, size, shape …

A Third-Order Non-Oscillatory Finite-Volume Transport Scheme For Atmospheric Modeling, Kiran Kumar Katta

Open Access Theses & Dissertations

Atmospheric numerical modeling has been going through drastic changes over the past decade, mainly to utilize the massive computing capability of the petascale systems. This obliges the modelers to develop grid systems and numerical algorithms that facilitate exceptional level of scalability on these systems. The numerical algorithms that can address these challenges should have the local properties such as the high on-processor operation count and minimum parallel communication i.e. high parallel efficiency, it should also satisfy the following properties such as inherent local and global conservation, high-order accuracy, geometric flexibility, non-oscillatory advection, positivity preservation.

In the present work, A Third-order …

Easterly Waves And Tropical Cyclogenesis In The Caribbean, Kay Louise Shelton

Legacy Theses & Dissertations (2009 - 2024)

This thesis is concerned with the evolution of easterly waves in the Atlantic and Caribbean and their relationship to tropical cyclogenesis. Motivation for this study is the apparent "genesis hole" in the eastern Caribbean and the lack of knowledge regarding the evolution of the transient disturbances passing through this region. The environment of the Caribbean is reviewed revealing large vertical wind shear and dry mid-levels as the key factors determining the presence of the genesis hole.

The Influence Of The Great Lakes On Mcs Formation And Development In The Warm Season, Alan Frederick Srock

Legacy Theses & Dissertations (2009 - 2024)

This study focuses on how near-surface thermal boundaries that form near the Great Lakes during the warm season can contribute to the formation of mesoscale convective systems (MCSs). Differential heating across land-water interfaces can create a cold dome of air over the lake; convection may develop when the relatively-cold dome of air becomes deep enough to enable air parcels that intersect these boundaries to reach their level of free convection. A radar-based climatology of MCS events surrounding the Great Lakes for 2002-2005 showed that MCSs frequently form in the vicinity of the Great Lakes. Composites of MCS events over the …

Review Of The Simulation Of The Precis Regional Climate Model Over Tropical South America Using Gcm And Reanalysis Lateral Boundary Conditions, Dana Mcglone

Legacy Theses & Dissertations (2009 - 2024)

High-resolution regional climate models (RCM) run over a limited domain are increasingly used to simulate seasonal to interannual climate variability over South America and to assess the spatiotemporal impact of future climate change under a variety of emission scenarios. Global climate models (GCM) are often too coarse to resolve local circulations and the topography of the Andes, leading to problems with simulation of temperature and precipitation patterns throughout the domain. A RCM model can also better represent the climate at a regional scale; however, they are subject to errors introduced by the driving global models. For this study, the Hadley …

Northeast United States Heat Waves : A Statistical Analysis And Synoptic Climatology, Scott Cooper Runyon

Legacy Theses & Dissertations (2009 - 2024)

The results of a statistical analysis of anomalously hot day and heat wave frequency in the United States (U.S.) are presented, along with a synoptic climatology of northeast U.S. heat waves (NHWs) for 1948-2001. This study used daily high temperatures retrieved from the National Climatic Data Center (NCDC) Daily Surface Dataset for 54 stations binned into the nine standard NCDC climate regions. Anomalously hot days were defined as when the daily high temperature exceeded the climatological 97.5-percentile temperature. Heat waves were defined as at least three consecutive anomalously hot days, whereas regional heat waves (e.g., NHWs) were defined as simultaneous …

The Downstream Extratropical Flow Response To Recurving Western North Pacific Tropical Cyclones, Heather M. Archambault

Legacy Theses & Dissertations (2009 - 2024)

The factors that govern the downstream flow response to recurving western North Pacific (WNP) tropical cyclones (TCs) are investigated from climatological, composite analysis, case study, and predictability perspectives. A 1979–2009 climatology of WNP TC recurvature indicates that TC recurvature is followed by a four-day period of above-normal North Pacific meridional flow. The relationship between TC recurvature and above-normal North Pacific meridional flow is found to be stronger in late summer through mid-fall than in early summer and early winter, and stronger for TCs that interact strongly with the jet stream than for TCs that interact weakly with the jet stream. …

Tropical-Extratropical Interactions And Arctic-Extratropical Interactions Conducive To Intraseasonal Variability Of The North Pacific Jet Stream, Jason Michael Cordeira

Legacy Theses & Dissertations (2009 - 2024)

The autumnal spin up of the Northern Hemisphere (NH) general circulation is characterized by intraseasonal variability in the structure of the North Pacific jet stream (NPJ). The variability in the structure of the NPJ is often associated with large-scale flow reconfigurations over the North Pacific and North America and changes in the NH zonal available potential energy (AZ). This dissertation investigates variability in the structure of the NPJ and the NH AZ in conjunction with tropical-extratropical interactions (TEIs) and arctic-extratropical interactions (AEIs). The former are investigated in association with the El Niño-Southern Oscillation, the Madden-Julian Oscillation, and western North Pacific …

Significance Of Hno3 Acid Photolysis On Surfaces In Tropospheric Chemistry, Honglian Gao

Legacy Theses & Dissertations (2009 - 2024)

The reactive nitrogen trace gases (NO_y) including nitrogen oxides (NO_x) and their secondary products are known to cause ground-level ozone pollution, photochemical smog, acid deposition, and overall air quality degradation. NO_x was believed to be permanently removed from the atmospheric by HNO₃ formation and deposition. However, our laboratory experimental results show that HNO₃ can be remobilized back to photochemically labile HONO and NO_x (re-NOx-ification). We have verified and quantified HONO and NO_x production from the photolysis of HNO₃ on various surfaces, including Pyrex, leaves of plants, and other environmentally relevant …

Origin And Maintenance Of The Stable Boundary Layer In A Patchy Landscape, Luiz Eduardo Medeiros

Legacy Theses & Dissertations (2009 - 2024)

Field observations made in Hudson Valley region, NY during the Hudson Valley Ambient Meteorology Study (HVAMS) are analyzed to examine how terrain and land cover influence nocturnal mixing in real-world landscapes. Important terrain features such as local topographic concavity and site sheltering are shown to exhibit systematic influence on turbulent intermittency and on the consequent nocturnal heat and momentum fluxes. Very local obstacles have their most important effects on mixing during strong winds (> 5m/s). Local terrain concavity was found to be the more important factor influencing surface fluxes than sheltering for all classes of winds.