Atmospheric Sciences Commons^™

Changes In Heat Metrics Following A Major Hurricane And Implications On Heat Stress, Cade Reesman

LSU Master's Theses

Tropical cyclones modify surface-atmosphere interactions in several ways, including the destruction of patches of tree canopy, increasing the direct and diffuse (shortwave) radiation reaching the surface. This addition of radiation at the surface impacts the sensible, latent, and substrate heat (energy) fluxes, generating heat anomalies along the hurricane’s track, which, among other effects, contributes to the higher post-hurricane surface air temperatures. This study consists of a case study on Hurricane Laura (2020) to examine hurricane defoliation impacts on heat stress metrics. Normalized difference vegetation index (NDVI) data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) identified the spatial extent of defoliation …

Murphy Scale: A Locational Equivalent Intensity Scale For Hazard Events, Yi Victor Wang, Antonia Sebastian

Institute for ECHO Articles and Research

Empirical cross-hazard analysis and prediction of disaster vulnerability, resilience, and risk requires a common metric of hazard strengths across hazard types. In this paper, the authors propose an equivalent intensity scale for cross-hazard evaluation of hazard strengths of events for entire durations at locations. The proposed scale is called the Murphy Scale, after Professor Colleen Murphy. A systematic review and typology of hazard strength metrics is presented to facilitate the delineation of the defining dimensions of the proposed scale. An empirical methodology is introduced to derive equivalent intensities of hazard events on a Murphy Scale. Using historical data on …

Detector Improvements And Optimization To Advance Gravitational-Wave Astronomy, Varun Srivastava

Dissertations - ALL

The thesis covers a range of topics relevant to the current and future gravitational-wave facilities. After the last science observing run, O3, that ended in March 2020, the aLIGO and VIRGO gravitational-wave detectors are undergoing upgrades to improve their sensitivity. My thesis focuses on the work done at the LIGO Hanford Observatory to facilitate these upgrade activities. I worked to develop two novel technologies with applications to gravitational-wave detectors. First, I developed a high-bandwidth, low-noise, flexure-based piezo-deformable mirror for active mode-matching. Mode-matching losses limit improvements from squeezing as they distort the ground state of the squeezed beam. For broadband sensitivity …

Knocking Down Nox: Examining The Effects Of Transportation Electrification On Urban Ozone Production In The South Coast Air Basin, Jason Beal

Macalester Journal of Physics and Astronomy

With last year’s commitment to all in-state sales of new passenger cars and trucks being zero-emission by 2035 (California Executive Order N-79-20), California is leading the charge for transportation electrification in the United States. Despite being at the forefront of climate change management and mitigation, California has some of the worst air quality in the nation. While primarily motivated by a desire to reduce carbon dioxide emissions and reliance on fossil fuels, transportation electrification will also have a significant impact on local air quality. The goal of this study is to quantify and qualify this impact in the context of …

Mesosphere And Lower Thermosphere Changes Associated With The 2 July 2019 Total Eclipse In South America Over The Andes Lidar Observatory, Cerro Pachon, Chile, A. Liu, F. Vargas, G. Swenson, C. Segura, P. Vega, J. Fuentes, D. Pautet, M. Taylor, Y. Zhao, Y. Morton, H. Bourne

Publications

This article presents the results of a week of observations around the 2 July 2019, total Chilean eclipse. The eclipse occurred between 19:22 and 21:46 UTC, with complete sun disc obscuration at 20:38–20:40 UTC (16:38–16:40 LT) over the Andes Lidar Observatory (ALO) at (30.3°S, 70.7°W). Observations were carried out using ALO instrumentation with the goal to observe possible eclipse-induced effects on the mesosphere and lower thermosphere region (MLT; 75–105 km altitude). To complement our data set, we have also utilized TIMED/SABER temperatures and ionosonde electron density measurements taken at the University of La Serena's Juan Soldado Observatory. Observed events include …

Remote Sensing & Land Surface Temperature From Satellite Observations, Isatu Jollah

Publications and Research

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument is designed and developed in 1995. • It is a critical instrument aboard Terra and Aqua satellites. Terra's orbit around the Earth is timed so that it crosses the equator from north to south in the morning, while Aqua crosses the equator from south to north in the afternoon. • Every 1 to 2 days, Terra MODIS and Aqua MODIS scan the entire Earth's surface, collecting data in groups of wavelengths. • In this research, a whole month of MODIS Land Surface Temperature data from both Aqua and Terra were explored and investigated.

Observations And Analysis Of The 7 October 2020 Derecho, Maxim Couillard

Atmospheric & Environmental Sciences

A serial derecho impacted Upstate New York and western Massachusetts on the afternoon of 7 October 2020, resulting in 120 damaging wind reports alonga 515-km swath. The magnitude and extent of this event was unexpected and not well forecast, motivating a closer examination. This study seeks to better understand the conditions prior to and during the derecho to diagnose what led to such a damaging wind event. The synoptic forcing for this event was an upper- level jet with a broad, negatively tilted trough over the northeast U.S. and southeast Canada. The upper-level pattern provided forcing for a 990-hPa surface …

Comparing Composite Severe Weather Indices Of Thunderstorm Activity On Sea-Breeze And Non-Sea-Breeze Days In The Mobile, Alabama Area, Elizabeth Seiler

Undergraduate Theses

Sea breezes (SB) occur frequently from May through October along the U.S. Gulf of Mexico Coast. One reason why SBs interest forecasters is their ability to spawn summertime thunderstorms, which can cause flash flooding, lightning, and hail. However, forecasting the exact timing and location of SB-driven convection can be challenging. This thesis will focus on Mobile and Baldwin Counties in southwest Alabama, which experience two types of phenomena – SBs along the Gulf of Mexico Coast and bay breezes on either side of Mobile Bay. Over the past years, multiple undergraduate students have analyzed Mobile, Alabama radar imagery of past …

Comparing Composite Severe Weather Indices Of Thunderstorm Activity On Sea-Breeze And Non-Sea-Breeze Days In The Mobile, Alabama Area, Elizabeth Seiler

Poster Presentations

Poster for the Honors Thesis project.

Sea breezes (SB) occur frequently from May through October along the U.S. Gulf of Mexico Coast. One reason why SBs interest forecasters is their ability to spawn summertime thunderstorms, which can cause flash flooding, lightning, and hail. However, forecasting the exact timing and location of SB-driven convection can be challenging. This thesis will focus on Mobile and Baldwin Counties in southwest Alabama, which experience two types of phenomena – SBs along the Gulf of Mexico Coast and bay breezes on either side of Mobile Bay. Over the past years, multiple undergraduate students have analyzed …

The Analysis Of Relationships Between Lightning Strikes And Particulate Matter 2.5 Utilizing Statistical And Numerical Modeling Methods Applied To The 2020 Wildfire Season, Megan Schiede

Atmospheric & Environmental Sciences

Throughout 2020, ambient air pollution was reduced as a result from limiting anthropogenic activities to mitigate the spread of COVID-19. Not all air pollution is created the same as measurements of particulate matter 2.5 (PM2.5) were generally unaffected by this reduction due to PM2.5s source from wildfires. Despite influences from COVID-19 lockdowns, rises in PM2.5 concentrations can be attributed to the anomalously active wildfire season of 2020. As climate change progresses, these extraordinarily active seasons can be classified as the “new normal”; thus, comprehension of such events are vital. Given the ability of lightning to naturally cause wildfires, there exists …

An Agent-Based Exploration Of The Hurricane Forecast-Evacuation System Dynamics, Austin Reed Harris

Theses and Dissertations

In the mainland US, the hurricane-forecast-evacuation system is uncertain, dynamic, and complex. As a result, it is difficult to know whether to issue warnings, implement evacuation management strategies, or how to make forecasts more useful for evacuations. This dissertation helps address these needs, by holistically exploring the system’s complex dynamics from a new perspective. Specifically, by developing – and using – an empirically informed, agent-based modeling framework called FLEE (Forecasting Laboratory for Exploring the Evacuation-system). The framework represents the key, interwoven elements to hurricane evacuations: the natural hazard (hurricane), the human system (information flow, evacuation decisions), the built environment (road …

Do State Fairs With Firework Displays Impact Pm2.5 Levels In Nearby Communities?, Victoria Lang

Theses and Dissertations

This study identified state fairs with known firework displays to evaluate whether they impact local air quality. Previous research has shown firework displays are linked with the short-term degradation of local air quality due to increased concentrations of fine particulate matter (PM2.5) as a result of the display. These studies observed increased PM2.5 concentrations associated with widespread firework displays such as the Lantern Festival in China, Diwali Festival in India, and Independence Day in the United States. However, it has not been investigated whether a signal of increased PM2.5 concentrations from firework displays during a state fair could be observed …

A Mesonet-Based Analysis Of Severe Convective Winds In West Texas., Quint Long

Electronic Theses and Dissertations

Multiple studies have investigated the occurrence of severe convective-related winds and have increased our understanding of the forces driving severe winds and their spatial and temporal patterns. Data for these studies have come from airport stations maintained by the National Weather Service. Their standardization across the United States makes them ideal for research, but they are limited in their distribution. This study aims to create a similar climatology of severe surface level winds using a mesoscale network (“mesonet”). Like their ASOS (Automated Surface Observing System) and AWOS (Automated Weather Observing System) counterparts, these stations are standardized and well maintained. This …

Acoustic Waves In The Upper Atmosphere, Geoffrey Blayne Schulthess

All Graduate Plan B and other Reports

Atmospheric waves can be generated by tropospheric sources such as earthquakes and explosions, causing significant disturbances in the upper atmosphere and ionosphere, where radio wave communications take place. For this analysis, they will be separated into two sub-groups called acoustic waves and gravity waves. Because each of these waves have unique frequency ranges, they can be observed and measured in order to determine their source type and location. Past studies attempted to build the connections between these waves with severe storms and earthquakes, which have improved our understanding of their complexity. Because of the complex nature of these waves, simplified …

The Impact Of Sea-Level Rise In Numerically Modeled Landfalling Hurricanes: Katrina And The Gulf Coast., Serenity Nadirah Mercuri

Electronic Theses and Dissertations

With climate change, landfalling hurricanes become an increasing threat to coastal regions. However, the interactions between the coastal landscape and landfalling hurricanes are often overlooked when addressing sea-level rise outside of inundation and independent of sea surface temperature. This study analyzed the potential impacts regarding structure and intensity as a result of sea-level rise in the Gulf of Mexico using the WRF-ARW numerical model coupled with a 1D ocean model. Analysis showed that 10 m windspeed from landfall forward was higher in modified coastlines, and minimum sea-level pressure post-landfall was consistently lower for modified runs where storms maintain a higher …

An Investigation Of Water Obstructions And Related Weather Conditions For Nebraska Roadways, Logan Bundy

Dissertations & Theses in Earth and Atmospheric Sciences

Roadway resilience across the 10,000 miles of road and 3,500 bridges in Nebraska is critical to the economic success of production and logistics. In a state where historical flooding scenarios, such as the one in March 2019 that caused $150 million in damage, could potentially be increasing, it has become essential to understand the spatial and temporal distribution of high-frequency water obstruction areas on roadways. Using Nebraska Department of Transportation (NDOT) historical water obstruction data from June 2016 through August 2021, statistical and spatial analyses were conducted to quantify the relationship between water obstructions and their associated meteorological conditions, and …

Odu’S Peter Bernath Participates In Study That Reveals Damage To Ozone Layer From Extreme Wildfires, Tiffany Whitfield

News Items

No abstract provided.

Global Gnss-Ro Electron Density In The Lower Ionosphere, Dong L. Wu, Daniel J. Emmons Ii, Nimalan Swarnalingam

Faculty Publications

Lack of instrument sensitivity to low electron density (N_e) concentration makes it difficult to measure sharp N_e vertical gradients (four orders of magnitude over 30 km) in the D/E-region. A robust algorithm is developed to retrieve global D/E-region N_e from the high-rate GNSS radio occultation (RO) data, to improve spatiotemporal coverage using recent SmallSat/CubeSat constellations. The new algorithm removes F-region contributions in the RO excess phase profile by fitting a linear function to the data below the D-region. The new GNSS-RO observations reveal many interesting features in the diurnal, seasonal, solar-cycle, and magnetic-field-dependent variations in the …

Oxygen Ion Escape At Venus Associated With Three-Dimensional Kelvin-Helmholtz Instability, Tong Dang, Xuanye Ma, Jiuhou Le, Binzheng Zhang, Tielong Zhang, Zhonghua Yao, John Lyon, Sudong Xiao, Maodong Yan, Oliver Brambles, Kareem Sorathia

Publications

How oxygens escape from Venus has long been a fundamental but controversial topic in the planetary research. Among various key mechanisms, the Kelvin-Helmholtz instability (KHI) has been suggested to play an important role in the oxygen ion escape from Venus. Limited by either scarce in-situ observations or simplified theoretical estimations, the mystery of oxygen ion escape process associated with KHI is still unsettled. Here we present the first three-dimensional configuration of KHI at Venus with a global multifluid magnetohydrodynamics model, showing a significantly fine structure and evolution of the KHI. KHI mainly occurred at the low latitude boundary layer if …

Intercomparison Of Four Microphysics Schemes In Simulating Persistent Arctic Mixed-Phase Stratocumulus Clouds, Zachary A. Cleveland

Theses and Dissertations

Persistent Arctic mixed-phase stratocumulus clouds (AMPS) are important to the surface radiation budget of the Arctic. Their presence produces warming within the boundary layer and at the surface and inaccurately forecasting AMPS can lead to large, erroneous temperature forecasts. A Large Eddy Simulation of a case study of a persistent AMPS cloud was conducted using the Advanced Research Weather Research and Forecasting (WRF-ARW) model. The case examined occurred near Oliktok Point, AK between 26 and 27 April, 2017. The produced cloud pattern and properties of four different microphysics schemes -- P3, Thompson, Morrison, and WSM6 -- are compared to observations. …