Meteorology Commons^™

Capturing High-Impact Weather In A Fine-Scale Climate Simulation Using The Model For Prediction Across Scales - Atmosphere (Mpas-A) V 7.0, James George Digilio Jr.

Graduate Research Theses & Dissertations

The research a long-term, high-resolution (15-km) global simulation using the Model for Prediction Across Scales – Atmosphere (MPAS-A) version 7.0, a community atmospheric modeling platform with unique capabilities for weather and climate research. This simulation spans 30 continuous years, covering water years 1990 through 2019 (i.e., 1 October 1989–30 September 2019) and is initialized with the European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA5). Sea surface temperatures and sea ice are prescribed and updated daily using the fine-scale (0.05°) Operational Sea Surface Temperature and Ice Analysis (OSTIA). To date, this is one of the few high-resolution MPAS-A simulations at …

Climate Change Effects On The 2022–2023 High Impact Series Of Atmospheric Rivers Along The United States West Coast, Hunter Martinez-Buehrer

Graduate Research Theses & Dissertations

Atmospheric rivers (ARs) are long, narrow bands of water vapor transport that are commonly associated with a low-level jet ahead of a cold front of an extratropical cyclone. When multiple ARs occur in succession of one another within a certain aggregation period, it is known as an AR family. ARs and AR families are important to the U.S. West Coast—and especially California’s—hydroclimate, providing both beneficial and hazardous precipitation to the region. Recent studies have suggested that not all ARs and, thus, AR families, respond similarly to a warming climate. Therefore, it is critical to better understand how climate change impacts …

Convective Modes Associated With Precipitation Exceeding Postfire Debris Flow Thresholds In The Southwestern United States, Anya M. Aponte Torres

Graduate Research Theses & Dissertations

Postfire debris flows can occur when surface-water runoff dislodges and carries a slurry of loose sediment and vegetation downslope, usually in steep, recently burned terrain. Short-duration, high-intensity rainfall embedded within short or long-duration rainstorms (e.g., thunderstorms and atmospheric rivers) is most commonly associated with this mode of debris-flow initiation. The typical horizontal grid spacings of global numerical weather prediction and general circulation models are too coarse to resolve these convective precipitation features, which poses an obstacle to short-term forecasting and investigating future trends in the frequency, magnitude, and characteristics of debris-flow generating rainfall. For this study, 15-minute precipitation and simulated …

Medium Range Prediction Of U.S. Severe Convective Storms, Robert Fritzen

Graduate Research Theses & Dissertations

Severe convective storms (SCSs) are responsible for billions of dollars of losses in the United States each year through hazards such as large hail, damaging convective wind gusts, and tornadoes. While techniques for forecasting these SCSs have improved over the years, a majority of these improvements focus on short term forecasting and nowcasting techniques. Little work has been done to analyze the recent advances in numerical weather prediction techniques, and to leverage these advances to the prediction of SCSs at the medium range (defined herein as lead-day 4--8). The primary objectives of this dissertation research are to: 1) explore the …

The Future Of Extreme Windstorms In The United States: Insights From Convection-Permitting Simulations, Kristie Kaminski

Graduate Research Theses & Dissertations

A derecho is a long-lived, convectively induced, extratropical windstorm that produces severe wind gusts and an affiliated damage swath across an extensive area. This peril can generate billions of dollars in losses and poses a significant risk to life, infrastructure, and wind-sensitive industries. While the response of severe convective storms to anthropogenic climate change has received much attention in the literature, research assessing the genitors of derechos—mesoscale convective systems—has focused on understanding potential changes in the United States hydroclimate, not their severe wind potential. To date, there has been no research investigating spatiotemporal changes to derecho activity in the context …

Convection Allowing Simulations Of Hail In Historical And Future Climate Epochs, Jillian Rose Goodin

Graduate Research Theses & Dissertations

This thesis investigates the potential impact of anthropogenic climate change on hail frequency and intensity, which poses a significant threat to life and property, accounting for annual insured losses of around $30 billion in the U.S. This approach uses convection-allowing dynamically-downscaled regional climate simulations using input data from NCAR's bias-corrected Community Earth System Model to simulate historical and projected future climate regimes under two greenhouse gas emission scenarios. A column maximum diameter hail diagnostic is simulated by the Weather Research and Forecasting regional climate model to identify instances of hail days and size to quantify changes in large hail frequency …

Historical And Potential Future Climate Of Extreme Daily Precipitation Over The Contiguous United States Using Convection-Permitting Simulations, Sylvia Stinnett

Graduate Research Theses & Dissertations

The impacts of anthropogenic climate change will be felt most strongly through changes in hazards such as extreme precipitation. The potential for extreme precipitation changes—both increases and decreases—may have significant societal impacts (e.g., agriculture production, loss of life and property). However, limited research has quantified future projected changes in extreme precipitation due to computational limitations and considerable time expenditure for convection-permitting simulations of substantial duration.This project sought to analyze changes in extreme daily precipitation—defined as the 99th percentile daily accumulated value—due to climate change in the contiguous United States (CONUS) using a dynamically downscaled and convection-permitting regional climate modeling framework. …

Climatology Of The Elevated Mixed Layer Over The Contiguous United States And Northern Mexico: 1979–2021, Margo Siciliano Andrews

Graduate Research Theses & Dissertations

Elevated mixed layers (EMLs) are an important influence on the severe convective storm climatology in the contiguous United States (CONUS), playing a role in storm generation, sustenance, and suppression. A function of the topography in the western CONUS and northern Mexico, EMLs are elevated layers of nearly dry adiabatic lapse rates and high potential temperature, typically with a capping inversion at their base. Although it is well-established that EMLs are primarily a warm-season phenomenon most frequent in the Great Plains, no research to date has examined their variability in-depth, or whether they have changed through time. This study creates an …

Weather-Related Carbon Monoxide Poisoning In The United States: 2000-2019, Bailey Raine Stevens

Graduate Research Theses & Dissertations

Carbon monoxide (CO) is a colorless, odorless gas that can cause injury or death if inhaled. CO is a frequent secondary hazard induced by the aftereffects of natural hazards as individuals, families, and communities will often seek alternative power sources for heating, cooking, lighting, and cleanup during the emergency and recovery phases of a disaster. These alternative power sources – such as generators, petrol heaters, and vehicles, exhaust CO – can ultimately build to toxic levels in enclosed areas. Ever-increasing environmental and societal changes combined with an aging infrastructure are increasing the odds of power failures during hazardous weather events, …

Trends In Observed And Simulated Radar Reflectivity For The 21st Century, Christopher Michael Battisto

Graduate Research Theses & Dissertations

The effects of climate change may influence the prevalence of regional atmospheric conditions supportive of hazardous convective weather (HCW). As a result, the possibility of an increase in the frequency, strength, and/or variability of thunderstorms and their high-impact hazards—including tornadoes, damaging winds, hail, and flash flood-producing downpours—has garnered much scientific and public interest. Radar reflectivity, which remotely assesses precipitation intensity, may be used to detect, track, catalog, and appraise HCW and their parent storms over broad spatiotemporal scales. Reflectivity may also be simulated with regional climate models, and recent, but limited, efforts using these simulation output have identified the potential …

Midwestern U.S. Diurnal Temperature Range: Spatial And Temporal Trends From 1900-2018, Kelly Ann Swaney

Graduate Research Theses & Dissertations

In the Corn Belt region of the United States, the twentieth century saw many land use changes as the land had been converted from the natural landscape to cropland. As the twentieth century progressed, numerous advancements occurred to increase the crop acreage, crop density, and amount of irrigated land. All of these changes contributed to higher rates of evapotranspiration, which put more moisture into the low levels of the atmosphere. This additional moisture played a role in changing the radiative fluxes and, as a result, the surface temperature. The Diurnal Temperature Range (DTR) is examined across the 1900 to 2018 …

Analysis Of Emissions Inventory Challenges Across The U.S. Supported By The Case Study Of Dekalb, Illinois, Using Clearpath, Emery Taylor Dhanens

Graduate Research Theses & Dissertations

The urgent need to address the destructive effects of climate change globally through mitigation and adaptation is clear. A useful tool for climate change mitigation is a greenhouse gas emissions inventory, which can be used to benchmark current emission levels and create future reduction goals. Emissions inventories in the United States are not currently required by the federal government, but many cities are nonetheless choosing to conduct these inventories and adopt greenhouse gas reduction goals. Inventory tools vary in terms of the methodologies behind emissions calculations, and previous studies have noted the comparability and consistency issue among inventories. This mixed-methods …

Environmental Discriminators For Significant Tornadoes And Hail In The U.S. Using Proximity Soundings, Cody Michael Converse

Graduate Research Theses & Dissertations

Over the last 50 years, the United States has experienced an increase in severe storm events that produced $1 billion in damages or greater. Much of this loss is attributed to significant tornadoes and hail associated with deep, moist convection. Improving forecasts for these significant events assist in mitigating the impacts of these events. Previous work has identified statistically significant environmental parameters associated with severe thunderstorms, but more research is needed in identifying statistically significant ingredients associated with environments that produce significant tornadoes and hail.

This thesis aims to answer the following question: “Can diagnostics commonly used to forecast for …

A Climatology Of Quasi-Linear Convective Systems In The U.S., Jacob Adam Strohm

Graduate Research Theses & Dissertations

Quasi-linear convective systems, or QLCSs, are a common, organized thunderstorm mode in the U.S. Over the last fifty years, severe weather research has focused on the supercell, but, recently, QLCSs have become an increasingly important area of study. Researchers and operational meteorologists realize that this morphology is difficult to forecast and may be responsible for a large proportion of the severe weather reports in the eastern two-thirds of the U.S. This study seeks to determine the degree to which QLCSs threaten humans and their assets by, first, assessing their climatology and, second, measuring their contribution to the severe report record. …