Atmospheric Sciences Commons^™

Synoptic Drivers Of Extreme Precipitation In The Upper Yuba Watershed Of California, Emma Nichole Russell

Dissertations and Theses

The United States state of California is vulnerable to both droughts and extreme precipitation events due to the timing and processes of precipitation in the region. California's annual precipitation is dependent on a few strong storms and in addition to its Mediterranean climate, leads to great variability in precipitation both within and across years. While efforts to reduce the impacts of extreme precipitation events have been implemented, forecasting for these events remains a challenge in regions with complex terrain and dynamic meteorological drivers. In order to improve forecasting and preparedness for such events, it is important to understand the range …

Fe-Rich X-Ray Amorphous Material Records Past Climate And Persistence Of Water On Mars, Anthony D. Feldman, Elisabeth M. Hausrath, Elizabeth B. Rampe, Valerie Tu, Tanya S. Peretyazhko, Christopher Defelice, Thomas Sharp

Geoscience Faculty Research

X-ray amorphous material comprises 15-73 wt.% of sedimentary rocks and eolian sediments in Gale crater. This material is variably siliceous and iron rich but aluminum poor. The presence of volatiles is consistent with the existence of incipient weathering products. To better understand the implications of this material for past aqueous conditions on Mars, here we investigate X-ray amorphous material formation and longevity within terrestrial iron rich soils with varying ages and environmental conditions using bulk and selective dissolution methods, X-ray diffraction, and transmission electron microscopy. Results indicate that in situ aqueous alteration is required to concentrate iron into clay-size fraction …

Balloon Borne Gps-Enabled Radiosondes That Enable Simultaneous Multi-Point Atmospheric Sensing With A Single Ground Station, Peter A. Ribbens

Doctoral Dissertations and Master's Theses

Radiosondes are balloon borne atmospheric instruments that are a critical tool for understanding dynamics in the lower layers of the atmosphere. The low-cost radiosondes developed in the Space and Atmospheric Instrumentation Lab have been further developed to improve the system's use as a science-quality atmospheric instrument that is unique in its ability to simultaneously track multiple sondes with a single ground station. Sensors to measure temperature and pressure were added to improve measurements of the atmospheric state. A printed circuit board shield and 3D-printed shell were designed to make mass manufacturing possible. A thermistor-based temperature sensor was developed and tested …

Toward Untangling Thunderstorm-Aerosol Relationships: An Observational Study Of Regions Centered On Washington, Dc And Kansas City, Mo, Mace Bentley, Tobias Gerken, Zhoujun Duan, Dudley Bonsal, Henry Way, Endre Szakal, Mia Pham, Hunter Donaldson, Lucie Griffith

School of Integrated Sciences - Faculty Scholarship

A multi-variable investigation of thunderstorm environments in two distinct geographic regions is conducted to assess the aerosol and thermodynamic environments surrounding thunderstorm initiation. 12-years of cloud-to-ground (CG) lightning flash data are used to reconstruct thunderstorms occurring in a 225 km radius centered on the Washington, D·C. and Kansas City Metropolitan Regions. A total of 196,836 and 310,209 thunderstorms were identified for Washington, D.C. and Kansas City, MO, respectively. Hourly meteorological and aerosol data were then merged with the thunderstorm event database.

Evidence suggests, warm season thunderstorm environments in benign synoptic conditions are considerably different in thermodynamics, aerosol properties, and aerosol …

Multi-Case Study Of Left-Flank Boundaries Within Supercells, Peyton B. Stevenson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

This study investigates the prevalence and significance of forward-flank convergence boundaries (FFCBs) and left-flank convergence boundaries (LFCBs) in shaping the structure and intensity of supercells, using observational data from various field projects. Unlike previous research focusing on individual cases, this study examines a diverse range of cases to provide comprehensive insights into the relationship between these boundaries and supercell characteristics such as intensity, longevity, and tornadogenesis. By analyzing high-resolution surface data, the research addresses the frequency, location, and intensity of these boundaries, and their impact on pseudo vertical vorticity, pseudo convergence, and density gradients. A total of 228 boundary identifications …

Design And Evaluation Of An Esa-Based Method Of Ensemble Subsetting For A Wofs (Warn On Forecast-Like System), Daniel J. Butler

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Forecasting severe thunderstorm environments in the southeastern United States can be challenging due to mesoscale heterogeneities such as shortwave troughs, pre-existing airmass boundaries, cold fronts aloft, low-level jets, dry air intrusions, and mesoscale lows. To combat these challenges, ensemble sensitivity analysis (ESA) may be applied to a Warn-on-Forecast (WOF)-like ensemble to improve forecasts of severe convection through ensemble weighting and subsetting. Ensemble-based weighting and subsetting uses ensemble members that most accurately represent the thunderstorm environment in areas of mesoscale heterogeneity. This study creates and evaluates the ensemble-based weighting and subsetting in four cases of severe thunderstorm occurrence. The open parameter …

Deciphering Water Quality And Algal Dynamics In Clear Lake Through Hyperspectral Analysis Using Emit Data, Wenzhao Li, Shahryar Fazli, Surendra Maharjan, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

This study evaluates the potential application of hyperspectral Earth Surface Mineral Dust Source Investigation (EMIT) remote sensing for monitoring harmful algal blooms (HABs) and water quality in Clear Lake, California. The research focuses on correlating the chlorophyll-a (Chl-a) concentrations with EMIT spectral signatures, using waterbody-wide statistical analysis of Chl-a and EMIT data sampling at various lake locations. Results demonstrate distinct spectral signatures associated with varying Chl-a levels, highlighting the potential of hyperspectral imaging in differentiating algae levels and assessing water quality variables. It also indicates the EMIT’s utility in filling data gaps and offering high-resolution monitoring. This study underscores the …

Linkages Of The 2022 Unprecedented Global Heatwave Events To Triple-Dip La Niña, Sachi Perera, Joshua B. Fisher, Mohamed Allali, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Heatwaves are influenced significantly by El Niño-Southern Oscillation (ENSO), which alters temperature and precipitation patterns throughout the world. Since 2020, we have witnessed a "triple dip" La Niña conditions persisting for three consecutive years resulting in severe weather and climate driven events globally. In this study, we identified the dominant frequency of Niño 3.4 Sea Surface Temperature (SST) signals and correlated them with regions experiencing unprecedented heat waves in 2022, namely, the Indian Ocean, the North Atlantic around England and Spain, and the Mediterranean Sea. The signal's power spectrum and its three highest power components are determined based on the …

Spatio-Temporal Analysis Of The Roadside Transportation-Related Air Quality (Startraq 2022): Data-Driven Exposure Analysis By Transportation Modes, Jaymin Kwon, Yushin Ahn, Steve Chung

Mineta Transportation Institute

Particulate matter (PM) pollution poses significant health risks, influenced by various meteorological factors and seasonal variations. This study investigates the impact of temperature and other meteorological variables on PM10 and PM2.5 levels in Fresno County, known for high air pollution. Multiple linear regression (MLR) and generalized additive models (GAMs) assess the significance of these relationships. Analyzing data from Fresno County, we examine PM10 and PM2.5 levels across "hot" (June to August) and "cool" (September to May) seasons. Findings indicate PM10, both MLR and GAM models identify statistically significant variables, excluding temperature and wind direction in each season. However, during the …

Radio Propagation Through Density Irregularities In The Auroral Ionosphere, Pralay Raj Vaggu

Doctoral Dissertations and Master's Theses

A radio wave propagating through a structured or turbulent ionosphere undergoes multiple effects, such as refraction, diffraction, etc., that distort the incident radio wave by inducing phase and amplitude fluctuations. These fluctuations are called ionospheric scintillation. Scintillation effects can be detrimental to Global Navigation Satellite Systems (GNSS) such as Global Positioning System (GPS), but the observed effects can be used as a tool to study the underlying plasma process that causes scintillation. Scintillation is commonly seen in equatorial and high-latitude regions. This study centers around the scintillation and its causative plasma processes that dominantly happen in the high-latitude ionosphere …

The Ecosystem As Super-Organ/Ism, Revisited: Scaling Hydraulics To Forests Under Climate Change, Jeffrey D. Wood, Matteo Detto, Marvin Browne, Nathan J.B. Kraft, Alexandra G. Konings, Joshua B. Fisher, Gregory R. Quetin, Anna T. Trugman, Troy S. Magney, Camila D. Medeiros, Nidhi Vinod, Thomas N. Buckley, Lawren Sack

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Classic debates in community ecology focused on the complexities of considering an ecosystem as a super-organ or organism. New consideration of such perspectives could clarify mechanisms underlying the dynamics of forest carbon dioxide (CO₂) uptake and water vapor loss, important for predicting and managing the future of Earth's ecosystems and climate system. Here, we provide a rubric for considering ecosystem traits as aggregated, systemic, or emergent, i.e., representing the ecosystem as an aggregate of its individuals, or as a metaphorical or literal super-organ or organism. We review recent approaches to scaling-up plant water relations (hydraulics) concepts developed for …

Establishment Of A Research Site At The Kennedy Mountain Campus For The Observation Of Airborne Particulate Matter, Alyssa Knaus

Undergraduate Theses, Capstones, and Recitals

This thesis explored particulate matter (PM) concentrations at two sites within the Colorado Front Range. The study utilized two models of PurpleAir PM sensors, Flex and SD-II, to provide real-time, accessible data on PM1, PM2.5, and PM10 mass concentrations with the goal of establishing the first research site at the Kennedy Mountain Campus (KMC). The first of the two sites used during this study was at a suburban location outside of Denver, CO. This period was used as an instrument intercomparison period in order to conduct instrument analysis. The initial findings from this period found significant correlations between PM concentration …

Monitoring Air Fluxes In Caves Using Digital Flow Metres, Claudio Pastore, Amir Sedaghatkish, Eric Weber, Nicolas Schmid, Pierre-Yves Jeannin, Marc Luetscher

International Journal of Speleology

Precise measurements of airflow within caves are increasingly demanded to assess heat and mass transfers and their impacts on the karst environment, including subsurface ecosystems, hydrochemistry of karst water and secondary mineral precipitates. In this study, we introduce a new, low-cost and lightweight device adapted to monitoring air fluxes in caves which addresses the need for reliable measurements, low power consumption, durability and affordability. The device was calibrated in a wind tunnel, showing the high accuracy and precision of the device. Field-related uncertainties were further investigated in a ventilated cave to determine the effect of local airflow conditions on the …

Phase Error Scaling Law In Two-Wavelength Adaptive Optics, Milo W. Hyde Iv, Matthew Kalensky, Michael J. Spencer

Faculty Publications

We derive a simple, physical, closed-form expression for the optical-path difference (OPD) of a two-wavelength adaptive-optics (AO) system. Starting from Hogge and Butts’ classic OPD variance integral expression, we apply Mellin transform techniques to obtain series and asymptotic solutions to the integral. For realistic two-wavelength AO systems, the former converges slowly and has limited utility. The latter, on the other hand, is a simple formula in terms of the separation between the AO sensing (i.e., the beacon) and compensation (or observation) wavelengths. We validate this formula by comparing it to the OPD variances obtained from the aforementioned series and direct …

Remote Profiling Of Atmospheric Turbulence: Enhanced Resolution With Stacked Rayleigh Beacons In Tardis, Benjamin C. Wilson

Theses and Dissertations

A stacked beacon turbulence profiling methodology has been introduced and applied to have increased profiling on the Turbulence and Aerosol Research and Investigation System (TARDIS). The model was derived and demonstrated the applicability through discussion on data processing and inversion processes. The methodology was applied for two different nighttime experiments, one in Summer and one in Fall. C 2 n profiles were derived into the 1300 m altitude ranges for both nights and the summer experiment was compared to a co-located DELTA Sky measurements and LEEDR generated Climatological profiles. The comparison implied promise in the methodology with additional work needed …

Development Of The Nebraska Department Of Transportation Winter Severity Index – Phase Ii, Mark Anderson, Curtis L. Walker, Thomas Kauzlarich

Nebraska Department of Transportation: Research Reports

For the Nebraska Department of Transportation (NDOT), the Nebraska Winter Severity Index (NEWINS) provided an independent framework to calculate a winter season’s severity by categorizing individual winter storms. However, one of the greatest limitations of NEWINS is that it is not predictive. Thus, this study builds on the previously developed NEWINS by creating a predictive winter storm severity index known as NEWINS-Predictive (NEWINS-P). The quantitative precipitation forecast, snow accumulation, ice accumulation, and surface wind speed parameters from the National Digital Forecast Database (NDFD) are used to develop the five components composing the NEWINS-P framework. These components consist of snow severity …

Investigation Of Volatility, Composition, And Gas-Particle Phase Partitioning Of Atmospheric Organic Compounds Through Novel Instrumentation And Techniques, Karolina Cysneiros De Carvalho

McKelvey School of Engineering Graduate Student Theses & Dissertations

Atmospheric aerosols are ubiquitous indoors and outdoors and their impact on human life on Earth is extensive. Aerosol particles scatter and absorb solar radiation, are key in the formation of clouds and precipitation, and can affect the abundance and distribution of greenhouse and atmospheric trace gases by physicochemical multiphase processes, thus they play an important role in regulating regional and global climate. On the other hand, poor indoor and outdoor air quality associated with high particulate matter (PM) levels is among the leading health risks worldwide, affecting life quality and expectancy by increasing the risk of cancer, cardiovascular and respiratory …

Atmospheric Circulation, Climate Change, And Related Impacts Over The Western United States, Graham Patrick Taylor

Dissertations and Theses

This dissertation characterizes the range of atmospheric circulation patterns and select associated meteorology impacting the northwest United States, the onset timing of rain and wind relevant to wildfire across the western United States, and how these may respond to global warming. The ability of a suite of models contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to simulate observed large-scale atmospheric circulation patterns over the Pacific Northwest of North America is evaluated. Climate model projections of atmospheric circulation patterns, their frequency, and associated temperature and precipitation anomalies under a high-end global warming scenario are assessed over …

Quantification Of Surface Layer Turbulence Using Sensible Heat Values From Energy Balance Versus Aerodynamic Methods, Steven T. Fiorino, Yogendra Raut, Jaclyn Schmidt, Laura Slabaugh, Blaine Fourman, Jack E. Mccrae, Benjamin C. Wilson, Santasri R. Bose-Pillai

Faculty Publications

Surface layer optical turbulence values in the form of the refractive index structure function C_n^2 are often calculated from surface layer temperature, moisture, and wind characteristics and compared to measurements from sonic anemometers, differential temperature sensors, and imaging systems. A key derived component needed in the surface layer turbulence calculations is the sensible heat value. Typically, the sensible heat is calculated using the bulk aerodynamic method that assumes a certain surface roughness and a friction velocity that approximates the turbulence drag on temperature and moisture mixing from the change in the average surface layer vertical wind velocity. These assumptions/approximations generally …

A Multi-Century Reconstruction Of Sea Surface Temperature, Salinity, And Density From A Northern Red Sea Coral., Daliza Nanette Rivera-Matos

Legacy Theses & Dissertations (2009 - 2024)

The Red Sea Outflow Water (RSOW), an intermediate water mass formed in the northern Red Sea, is a primary Red Sea water circulation process. Understanding these water circulation processes gives us an insight into this region's climate dynamics. The intermediate water formation is one of the main processes of the water circulation in the northern Red Sea and feeds the Indian Ocean with saltier and colder water. Despite understanding the RSWO's association with the North Atlantic Oscillation (NAO), its historical response to this climate mode remains unclear. There has not been a long-term record to analyze the relationship between the …

Understanding Variations And Trends In Convection Over The Congo Basin From A Diurnal Perspective, Kathrin Alber

Legacy Theses & Dissertations (2009 - 2024)

Tropical rainforests regulate global and regional climate systems and play a vital role in the world’s water and carbon cycles. The Congo Basin, situated in central equatorial Africa, is home to the second largest rainforest on the planet and is one of the most convective regions in the world. Recent studies indicate that a large-scale and long-term drying trend, characterized by an increase in dry season length, a decrease in forest greenness, and a decrease in precipitation, has been stressing the region since the 1980’s. Despite the alarming drying trend and the Congo’s important role in the planetary circulation and …

The Impact Of Wildfire Activities On Air Quality And Solar Energy In New York And California, Chin-An Lin

Legacy Theses & Dissertations (2009 - 2024)

An increasing trend of wildfire activity over North America over the past decades has been observed. Elevated surface fine mode particulate matter (PM2.5) concentration and reduction of solar radiation during the smoke episodes have been widely reported. Given that the intensity and frequency of wildfires are expected to increase under changing climate, the impact of smoke aerosols on air quality and solar energy could become more significant. This study aims to characterize the transport of smoke aerosols and quantify their impact on local air quality and solar energy over New York (NY) and California (CA) States. A multi-year analysis of …

Cultural And Environmental Change In A Period Of Westernized Tourism: Bali, Indonesia, Barbara Buck

ALL - Honors Theses

Dutch colonizers opened Bali for tourism at the beginning of the 20th century, and since that time tourism has led to changes in Bali’s culture, environment, and local resources. In the late 1900s, tourism grew to a new level, which resulted in a shift of industry control away from Balinese people. This project examines the problem of tourism from a social and environmental science lens. By compiling literature and science from various fields of study, this project aims to illustrate the complexity of Bali’s tourism problem in an interdisciplinary way. The lack of local control over tourism perpetuated and exacerbated …

Categorizing The Societal Impacts From Extreme Rainfall In The New York City Metropolitan Area, Evan Belkin

ALL - Honors Theses

Numerous studies have shown that the frequency and intensity of extreme rainfall events have increased significantly across the contiguous United States (CONUS) over the past several decades associated with warming global temperatures. This surge in extreme rainfall has resulted in the loss of life and property within vulnerable communities due to widespread river and flash flooding. For example, 11 of the 14 fatalities in New York City associated with Tropical Cyclone Ida’s remnants in September 2021 occurred in flooded basement apartments. The creation of a scale to differentiate extreme rainfall events with higher societal impacts from those with lower impacts …

Diurnal To Seasonal Hurricane Variability And Predictability, Jeremiah Otero Piersante

Legacy Theses & Dissertations (2009 - 2024)

Prediction of tropical cyclone (TC) impact extends across a range of forecast lead times. At shorter timescales, radially outward-propagating, diurnal pulses in TCs are associated with TC intensity and structure changes. At weekly periods, synoptic-scale Rossby waves influence the direction of TC tracks. At seasonal timescales, climate modes affect the overall (in)favorability of TC activity. The research shown in this dissertation seeks to improve the understanding and predictability of TC variability across these scales using numerical weather prediction, reanalysis fields, and storm track observations.Diurnal pulses associated with cloud-top cooling, so-called cooling pulses (CPs), pose a risk for hazardous weather because …

Examining The Performance Of The High-Resolution Rapid Refresh Model During Clear, Isolated, And Widespread Convective Days In The New York State Capital Region, Rachel A. Eldridge

Legacy Theses & Dissertations (2009 - 2024)

Forecasting can be more challenging in areas of complex terrain, such as in and around the valleys and mountains of Upstate New York. Biases in numerical weather prediction models, related to the lack of resolution of the terrain and errors in physical parameterizations, can affect forecasts. The main goal of this research is to assess biases in the High-Resolution Rapid Refresh (HRRR) model that could contribute to deficiencies in forecasts for days with and without convection. We investigate how the HRRR model performed in the New York Capital Region for 4 clear days, 4 isolated convective days, and 4 widespread …

Understanding The Zonal Variability In Cmip6 Projections Of Sahelian Precipitation, Emmanuel Ogwuche Audu

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The uncertainty in model projections of future precipitation across the Sahel has persisted across many generations of Earth System Models (ESMs), with some models predicting drying and others moistening across this region. These discrepancies in future projections pose a challenge for stakeholders and decision makers. Many projections of Sahel precipitation found in the ESMs participating in the sixth phase of Coupled Model Intercomparison Project (CMIP6) show a zonal dipole in precipitation trend, with moistening across the Central and Eastern Sahel and drying projected for the Western Sahel. Previous studies have connected precipitation variability across the Sahel to changes in various …

Polarimetric Radar Signatures In Significant Severe Left-Moving Supercells, Raychel Nelson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Left-moving (LM) supercells, though rarer than right-moving (RM) supercells, may produce significant severe weather. However, there are very few existing studies on LM supercells, particularly polarimetric radar analyses. The upgrade of the nationwide Weather Surveillance Radar-1988 Doppler (WSR-88D) network to polarimetric capability and subsequent studies vastly improved understanding of RM supercells, but similar efforts have largely not been made for LM supercells. This study employs an automated polarimetric radar signature detection algorithm to examine a dataset of significant severe (hail ≥ 2.00”, wind ≥ 65 kts) LM supercells to quantify their polarimetric signatures. Comparisons are made with RM supercells to …

A Dual-Polarimetric Analysis Of A Large Sample Of Left-Moving Supercells, Ben Schweigert

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Supercells have been researched extensively since they were first described over 50 years ago. They are prolific severe weather producers, responsible for the most severe hail, severe wind gusts, and tornadoes. These rotating thunderstorms require attention from forecasters to protect life and property from their threats, most effectively done with Doppler radars. While extensive amounts of radar-based investigations have been completed, they focused almost exclusively on right-moving (RM) supercells, resulting in a knowledge gap surrounding their counter-rotating (left-moving, LM) partners. This study works to fill the void by developing a dataset of LM supercells and analyzing the dual-polarimetric features observed …

Deterministic Global 3d Fractal Cloud Model For Synthetic Scene Generation, Aaron M. Schinder, Shannon R. Young, Bryan J. Steward, Michael L. Dexter, Andrew Kondrath, Stephen Hinton, Ricardo Davila

Faculty Publications

This paper describes the creation of a fast, deterministic, 3D fractal cloud renderer for the AFIT Sensor and Scene Emulation Tool (ASSET). The renderer generates 3D clouds by ray marching through a volume and sampling the level-set of a fractal function. The fractal function is distorted by a displacement map, which is generated using horizontal wind data from a Global Forecast System (GFS) weather file. The vertical windspeed and relative humidity are used to mask the creation of clouds to match realistic large-scale weather patterns over the Earth. Small-scale detail is provided by the fractal functions which are tuned to …