Atmospheric Sciences Commons^™

The Urban Heat Island And Its Role In Shaping Convective Environments: An Observational Study, Benjamin W. Moll

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

The continued spread of urbanization and its well-documented effects on regional weather and climate necessitate further research. Urban environments are often warmer and drier than their rural surroundings. This trade-off between a warmer but drier environment could have a complex impact on deep convection and its initiation. Previous studies have noted significant changes in precipitation patterns around cities as well as changes to ongoing deep convection. Given the well-documented theory and past research, it is hypothesized here that urban areas have a significant impact on the PBL thermodynamics of convective environments. The urban heat island (UHI) component of the Micro …

Modeling Aerosol Transport During High Particulate Matter Episodes In El Paso-Juarez Region And Mitigating Mining-Related Emissions Of Rare Earth Elements (Rees) To The Air, Suzan Aranda Luna

Open Access Theses & Dissertations

This dissertation examines the use of the HYSPLIT model to develop a methodology for the transport and dispersion of air masses affecting particulate matter (PM) concentrations in the El Paso Region, and bioleaching experiments as an alternative to mitigating rare-earth concentrations in the air. Chapter 2 describes the study methodology, 3 and 4 cover the modeling methodology using two-representative high PM2.5 episodes, occurring on February 28, 2024, and June 19, 2024, respectively. These sections encompass the analysis of backward trajectories using four different meteorological datasets to build trajectory frequency maps, the exploratory model analysis of modeled outputs from lower to …

Rainfall-Runoff Modelling In An Indonesian Humid Tropical Area Using Satellite-Based Precipitation Products, Noordiah Helda

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation explores three rainfall-runoff models in the humid tropical regions of Indonesia using satellite-based precipitation products (SBPPs) and develops integrated machine-learning modeling frameworks. Several ground-based observations from BMKG (Badan Meteorologi, Klimatologi, dan Geofisika (also known as the Indonesian Agency for Meteorology, Climatology, and Geophysics)) stations across Indonesia (133−165 stations) are compared and evaluated against satellite products, indicating that GPM performs well, with R-squared values ranging from 0.54 to 0.76 and correlation coefficients ranging from 0.45 to 0.69, respectively.

In the Martapura Watershed, South Kalimantan, due to a lack of observational discharge data, streamflow was generated using the FJ Mock …

Aluminum As A Tracer Of Dust Deposition To The Ocean: A Case Study From The Bermuda Region, Tara Elizabeth Williams

OES Theses and Dissertations

Aluminum (Al), a major component of mineral aerosol (dust), partially dissolves in seawater and is widely used as a tracer for estimating time‐averaged dust fluxes to the ocean. Such estimates rely on dissolved Al (DAl) inventories in the surface mixed layer (SML), an assumed SML residence time of DAl (_TDAl), the fractional solubility of Al in dust (Al_S), and the mass fraction of Al in dust. In this study, dust flux estimated from seasonal, water-column DAl data from the Bermuda Atlantic Time-series Study (BATS) region are compared with direct dust flux estimated from contemporaneous measurements of …

Climate Change Has Increased Global Evaporative Demand Except In South Asia, Saeed Karimzadeh, Arman Ahmadi, Dennis Baldocchi, Joshua B. Fisher

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Climate change alters how strongly the atmosphere draws water from the land, yet a consistent global assessment of this evaporative demand has been lacking. Here, we analyze 45 years of climate data and global models to quantify trends in the key drivers—air temperature, humidity, radiation, wind speed, and cloud cover—that determine the atmosphere’s drying power. We find that evaporative demand has increased worldwide, indicating a stronger atmospheric thirst, except in South Asia, where it has declined. There, widespread irrigation has increased soil and air moisture, enhanced cloud formation, and reduced sunlight reaching the surface, counteracting the global signal. These contrasting …

An Objective Method To Locate Shear Lines During The Northeast Monsoon Season In The Philippines, Lyndon Mark P. Olaguera, John A. Manalo, Jun Matsumoto, Faye Abigail T. Cruz, Jose Ramon T. Villarin

SOSE Affiliate: Manila Observatory

The shear line is a narrow zone of maximum horizontal wind shear, typically identified as a confluence zone of low-level wind streams. Previous studies showed that this system can trigger heavy to extreme rainfall events in the Philippines during the northeast monsoon season. However, a research gap remains in objectively identifying and locating this system. Thus, this study develops a detection method that may be used for monitoring and forecasting the location of shear lines. Results show that the gradient of meridional winds in the y-direction (∂V925hPa/∂y), the boundary layer moisture flux convergence, and the 925 hPa relative vorticity may …

Characterizing Meteorological Patterns For Oregon's Winter Elevated Pm2.5 Concentrations From 2000-2023, Arielle Golda Sherbak

Dissertations and Theses

Valleys and basins are uniquely susceptible to the buildup of air pollution during the wintertime due to cool, dense air pooling under favorable meteorological conditions, a common occurrence in the Intermountain West. In Oregon, wintertime anthropogenic air pollution is primarily from woodburning stoves and heaters and although efforts have been made to reduce wintertime pollution, stagnation events continue to result in decreased air quality. This analysis aims to understand the relationship between air pollution in six Oregon counties and the associated meteorology in the cool season (November-March) using a 2000-2023 climatology.

This is completed through a composite analysis using key …

Unraveling Crop Nitrogen-Water Dynamics With Hyperspectral-Thermal Sensing In Northern Central Valley, California, Shahryar Fazli, Surendra Maharjan, Wenzhao Li, Joshua B. Fisher, Rejoice Thomas, Fernando Romero Galvan, Gabriela Shirkey, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Ensuring global food security in the face of climate change requires optimizing crop water use and nutrient management. This study investigates the relationship between canopy nitrogen (N) and evapotranspiration (ET) across sunflower, rice, walnut, alfalfa, and plum crops using advanced remote sensing technologies. High-resolution hyperspectral data from NASAs Earth Surface Mineral Dust Source Investigation (EMIT) and thermal multispectral data from the Landsat-based OpenET system were analyzed over 1,135 km² in California. Regression analysis revealed strong spatial association between canopy N and ET for sunflower (R² = 0.82), rice (R² = 0.71), and walnut (R² = 0.68), …

Stream Temperature Responses To Summer Urban Rain Events Along The Savannah River, Joseph E. Wermter, Vivian L. Turner, Max K. Appelbaum, James M. Shepherd, Jacob Z. Lott

Journal of South Carolina Water Resources

The hydrological urban heat island (HUHI) is a recent facet of the urban heat island (UHI), describing thermal enhancement of bodies of water in response to urbanization. Although the forefront of this work has been studied for large Metropolitan areas, this effect on developing cities is currently unknown. To locally measure and quantify HUHI effects in a developing city, we utilized Multi-Radar Multi Sensor (MRMS) radar-derived rainfall data to estimate rainfall in the Augusta Metropolitan Area (AMA) and the Savannah Metropolitan Area (SMA), two developing communities adjacent to the Savannah River. We analyzed mean temperature trends of two stream gauges …

Multimodel And Multidiagnostic Ensemble-Based Deep Convective Area Forecast For Aviation Operations Using The Global Unified Model And Korean Integrated Model, Yi-June Park, Jung-Hoon Kim, Dan-Bi Lee, Hyun-Joo Choi, Soo-Hyun Kim, Matthias Steiner, Seung Hee Kim

Institute for ECHO Articles and Research

To provide safe and efficient guidance for aircraft operation to avoid deep convective areas (DCAs) in Korea and broader East Asia, we developed a multimodel and multidiagnostic ensemble (MMDE)-based forecast system. This system utilizes two global numerical weather prediction (NWP) models based on the Unified Model (UM) and the Korean Integrated Model (KIM) operated by the Korea Meteorological Administration. To predict hazardous weather conditions, we defined DCAs using ground-based radar mosaic data where the 15-dBZ echo-top height exceeds flight level (FL) 250 (about z = 6.5 km) and FL350 (about z = 9 km). For predictors, we employed a …

Validation And Proposed Expansion Of The Data-Driven D Region Model, Kevin M. Watson

Theses and Dissertations

Predicting ionosphere effects on radio wave propagation is critical for communications and over-the-horizon radar systems. The D region is challenging to model for several reasons, one of which is chemical complexity. Ion density changes during sunrise/sunset introduce substantial uncertainty in electron density profiles (EDPs). The Data Driven D Region (D3R) model solves electron densities through an ion chemistry model and assimilates relevant space weather inputs. This study evaluates D3R against the Faraday International Reference Ionosphere (FIRI) and measurements using Very Low Frequency (VLF) propagation paths. Space weather event impacts on D3R EDPs are evaluated during the disturbed period from 8-12 …

A Deep Learning Framework With Explainable Ai For Atmospheric Blocking Detection And Interpretation, Devansh Khandelwal

Discovery Undergraduate Interdisciplinary Research Internship

Atmospheric blocking is a large-scale quasi-stationary phenomenon in mid-latitude circulation, characterized by persistent high-pressure systems that disrupt the typical west-to-east flow of the jet stream. These systems can cause extreme weather events—such as heatwaves, cold spells, or droughts—that persist for days or even weeks. This study proposes a deep learning framework to predict and interpret the occurrence of atmospheric blocking by integrating geophysical precursors such as geopotential height (Z500), stream function (SF200), and potential vorticity. These features, which are dynamically linked to blocking onset and persistence, serve as inputs to a Convolutional Neural Network model trained on the CESM Large …

Low-Level Polarimetric Signatures Of Supercells During Ef3+ Tornado Production, Anthony Noah Began

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

Most EF3+ tornadoes are produced by supercells. Understanding of microscale features surrounding intense tornado production remains limited. This research aims to determine commonalities in low-level microphysical processes during intense tornado production via polarimetric radar signature assessment with a Python-based algorithm. Polarimetric variables hypothesized to reflect low-level wind profiles such as the differential reflectivity (Z_DR) arc and the Z_DR–K_DP (specific differential phase) separation vector will be investigated. Supercells which produced EF3+ tornadoes will be examined since these tornadoes pose the highest threat. From 2010 to 2024, the United States recorded approximately 19,100 tornadoes which resulted in …

Surveys And Modeling: Using An Existing Survey To Describe And Compare Populations To Better Inform On Groundwater Model Inputs, M. Austin Wise

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

The Mississippi River Valley “Alluvial Aquifer” is among the most agriculturally significant aquifers in the United States. However, parts of the aquifer are exceeding sustainable yield as development of the water source continues. Survey research in other aquifers, such as the High Plains (Ogallala) Aquifer, has helped to understand the perceptions and attitudes of irrigators withdrawing from their aquifers. This led to numerous questions: What are the attitudes of irrigators in the Alluvial Aquifer region? How do they compare to irrigators in other regions of the country? Can their intentions be used to generate more accurate inputs when modeling adoption …

Environmental Controls Of Hail In Quasi-Linear Convective Systems, Cameron A. Barker

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

A study of hail occurrence in quasi-linear convective systems (QLCS), as well as severe weather parameters contributing to the likelihood and intensity of hail, is presented. Rapid Refresh (RAP) proximity soundings for 218 QLCS events from 2012 to 2022 are selected to sample QLCS environments near peak intensity. Study objectives are to assess common environmental parameter spaces that favor hail in QLCSs while connecting these findings to results for supercells. Hail occurrence is also examined in terms of synoptic regime.

Six synoptic regimes were identified to support QLCSs with hail, from high shear, low cape (HSLC) to low shear, high …

Development And Evaluation Of Supported Ionic Liquid Membrane And Porphyrin Frameworks For Carbon Capture Separation, Sarang Ismail

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The global urgency to mitigate anthropogenic CO₂ emissions has intensified the pursuit of energy-efficient separation technologies. Supported Ionic Liquid Membranes (SILMs) have emerged as promising candidates for CO₂ capture due to their tunable solubility-selectivity and low energy requirements. However, challenges such as mechanical instability, limited scalability, and trade-offs in transport performance have impeded their widespread adoption.

This thesis explores a systematic approach to designing and optimizing SILMs for enhanced CO₂ separation by tailoring polymer–ionic liquid interactions, processing conditions, and material architectures. A comprehensive set of studies were conducted using poly(vinylidene fluoride) (PVDF) with varying molecular weights, different grades of PEBAX®, …

Simulation Of Photochemical Effects On Air Quality, Grace Li

Chemical Engineering Undergraduate Honors Theses

Nitrogen dioxide (NO₂) and ozone (O₃) are both EPA criteria air pollutants in the troposphere, largely generated by combustion and therefore present in significant concentrations in urban areas. Sunlight facilitates chemical reactions between pollutants and ambient air. Aerosols modulate the amount of available energy required to drive such photochemical reactions, ultimately impacting air quality. Simulating photolysis rates with FastJX software is a resource-efficient strategy to study how these aerosols can affect air quality.

Experimental Investigation Of Photovoltaic Soiling Losses And Aerosol Absorption And Scattering Related To Dust In The Chihuahuan Desert Region, German Rodriguez Ortiz

Open Access Theses & Dissertations

This dissertation explores the interaction between mineral dust and solar radiation in the Chihuahuan Desert, one of the dustiest areas in North America. I focused on two main aspects: (1) the characterization of atmospheric aerosol optical properties during dust events, and (2) the effects of dust deposition (soiling) on the performance of photovoltaic (PV) modules. I characterized the intrinsic optical properties of aerosols in El Paso, Texas during the peak of the 2021 dust season. Ground-level, high-resolution optical and meteorological data were collected at the Black and Brown Carbon (BC^2) study site, whereas particulate matter and additional meteorological parameters were …

Seeking Structure In Complex Systems: From Feature Analysis To Space-Time Causal Discovery With Earth Science Applications, Jeffrey J. Nichol

Computer Science ETDs

Complex systems are difficult to study because of their many interacting parts, emergent phenomena, and feedback loops. These systems underpin all life on Earth. We need improved tools for seeking an understanding of them. This body of research presents my investigations into data-driven methods for understanding complex systems, including my invention of a novel causal discovery meta-algorithm for space-time gridded data. I demonstrated machine learning feature importance and causal discovery capabilities for comparing simulated and observed climate data. I developed a new benchmark for modeling space-time dynamics of locally driven phenomena and examined a prominent causal discovery algorithm. Finding that …

Data Supporting The Paper "Enhancing Turbulent Mixing And Microphysical Uniformity In A Tall Convection-Cloud Chamber Through Idealized Heterogeneity Of Boundaries", Lois Thomas, Fan Yang, Aaron Wang, Mikhail Ovchinnikov, Kyle G. Pressel, Raymond Shaw

Michigan Tech Research Data

A large convection cloud chamber has been proposed for exploring aerosol–cloud–drizzle interactions under well-controlled turbulent conditions. Recent theoretical and numerical studies suggest that a convection cloud chamber with two heated and two cooled sidewalls can significantly enhance the liquid water content and thus benefit drizzle initiation. However, a chamber with such a sidewall configuration develops stable stratification and extremely weak turbulence therein. In this study, we conduct large-eddy simulations of a tall convection chamber with five different sidewall configurations consisting of alternating warm and cold patches. For each configuration, the total surface area of warm patches equals that of cold …