Atmospheric Sciences Commons^™

Characterizing Differential Reflectivity Calibration Dependence On Environmental Temperature Using The X-Band Teaching And Research Radar (Xtrra): Looking For A Relationship Between Temperature And Differential Reflectivity Bias, Emma Miller

The Journal of Purdue Undergraduate Research

Calibration scans are important for the maintenance of data and the quality of the information that radars output. In this study we looked for a temperature dependency in a full year’s worth of differential reflectivity (ZDR) calibration scan data collected by the X-band Teaching and Research Radar (XTRRA) located near the Purdue University campus. In a vertically pointing calibration scan, the radar scans the drops from below while rotating. From this angle, the overall shape will be circular, which corresponds to a ZDR value of approximately 0 dB. To process the data for the year 2021, a Python script was …

A Climatology Of Mesoscale Airmasses With High Theta-E, Charles J. Kropiewnicki

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

A Mesoscale Airmass with High Theta-E (MAHTE) is a narrow region of larger theta-e located on the cool side of an airmass boundary. MAHTEs typically possesses higher CAPE than the warm side of the boundary, creating a more favorable environment for severe convection. MAHTEs can also be characterized by larger low-level shear and lower LCLs and may also have a propensity for supporting tornadogenesis. The majority of MAHTE research to date has been comprised of case studies, and the prevalence of MAHTEs is not well understood. This project fills that knowledge gap by creating a climatology of MAHTE occurrence. This …

An Empirical Examination Of The Environmental Variability That Impacted Supercell Evolution, Longevity, And Severe Weather Production On 22 May 2019 In Oklahoma, Kyle D. Pittman

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

Mesoscale environmental heterogeneity can have significant impacts on thunderstorm organization, evolution, longevity, and severe weather production. This study examines the 22 May 2019 thunderstorm event in Oklahoma, where a relatively broad area of strong instability and vertical wind shear existed along a synoptic boundary and in the open warm sector that would seem to support long-lived supercells and tornadoes. There were two particularly dangerous situation (PDS) tornado watches issued during the event, but few severe reports and no tornadoes formed in the watch that covered the southwestern portion of the state. Several tornadic supercells and many more severe reports occurred …

Effect Of Morphology And An Upstream Tall Building On A Street Canyon Flow, Haoran Du

Electronic Thesis and Dissertation Repository

The effects of the morphological model and the existence of an upstream tall building on the turbulent street canyon flow and the overlying boundary layer are investigated in a wind tunnel, using Stereoscopic Particle Image Velocimetry (S-PIV) measurements. The velocity variances, Reynolds shear stress, and turbulent kinetic energy are found to be larger than in a similar idealized street canyon model. Increasing building height results in a decrease in vertical mass fluxes across the opening of the canyon, at least in the canyon portion directly downstream of the building. The interaction between the large-scale structures in the overlying boundary layer …

Hyper-Local Weather Predictions With The Enhanced General Urban Area Microclimate Predictions Tool, Kevin A. Adkins, William Becker, Sricharan Ayyalasomayajula, Steven Lavenstein, Kleoniki Vlachou, David Miller, Marc Compere, Avinash Muthu Krishnan, Nickolas Macchiarella

Publications

This paper presents enhancements to, and the demonstration of, the General Urban area Microclimate Predictions tool (GUMP), which is designed to provide hyper-local weather predictions by combining machine-learning (ML) models and computational fluid dynamic (CFD) simulations. For the further development and demonstration of GUMP, the Embry–Riddle Aeronautical University (ERAU) campus was used as a test environment. Local weather sensors provided data to train ML models, and CFD models of urban- and suburban-like areas of ERAU’s campus were created and iterated through with a wide assortment of inlet wind speed and direction combinations. ML weather sensor predictions were combined with best-fit …

Verification Of The Localized Aviation Mos Program (Lamp) At Major Us Airports For Ifr Conditions, Mackenzie O'Rourke

Theses and Dissertations

The objective of this research is to quantify the LAMP’s performance when forecasting for IFR conditions at specific major airports for forecast hours one, three, six, and twelve, and further determine how the LAMP performs seasonally at those specific airports and forecast hours. Two by two contingency tables were used to calculate the Probability of Detection (POD), False Alarm Ratio (FAR), Critical Success Index (CSI), Heidke Skill Score (HSS), and Bias score. The results show that the LAMP performs relatively better in the cool season compared to the warm season consistently at each chosen airport, and that the LAMP performs …

Atmospheric Impacts From The 2010 Deepwater Horizon Oil Spill, Charles Philip Johnson

LSU Master's Theses

Although the ecological devastations induced by an oil spill are well studied, the hydrometeorological impacts from a long-term slick have gone unnoticed. The ocean-surface alterations stemming from the lasting oil footprint increase solar radiation absorption which in turn alters the surface pressure and moisture gradients and wind speeds thereby influencing precipitation surrounding the oil spill. Revealing the potential impacts from these could better aid in the safety of crews cleaning spills and provide a better understanding of how humans alter the landscape. This thesis examines the changes in local hydrometeorology brought on by the 2010 summer Deepwater Horizon (DWH) oil …

Radar Signatures In Tropical Cyclone Tornadic And Nontornadic Supercells, Michaela Wood

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

Tropical cyclones (TCs) contain highly-sheared environments that are conducive for supercell thunderstorms. These TC supercells sometimes produce tornadoes, often with little warning. Given the often-close proximity of tornadic and nontornadic TC supercells, environments may not be well-distinguished, pointing to the potential value of radar observations. In this study, dual-polarimetric radar signatures of a sample of TC supercells are examined in the context of known supercell structure and microphysics. Tornadic and nontornadic TC supercells are compared with their midlatitude counterparts, and the environments and characteristic structure of these storms are shown to be notably different. An attempt is made to distinguish …

An Analysis Of Hurricane Laura's Storm Surge In Cameron Parish Using Synthetic Storm Tracks, Climatology, And Statistics, Cameron Goff

LSU Master's Theses

Cameron Parish is a large coastal parish in southwest Louisiana that has been impacted by several powerful tropical cyclones. In 2020, the strongest hurricane in recorded history to ever hit this region, Hurricane Laura, set a state record for the highest storm surge measurement at 6.34 meters. I examine the climatology of tropical cyclone landfalls in this parish, looking for trends in intensity and frequency with time. I then compare the extreme surge of Hurricane Laura with a dataset of 645 synthetic tropical cyclones generated and used by the Coastal Hazards System for Louisiana. Plots comparing various meteorological statistics to …

Spatial And Temporal Characteristics Of Historical Surface Climate Over The Northwest Territories, Canada, Bhaleka D. Persaud

Theses and Dissertations (Comprehensive)

Climate change is putting many of the Northwest Territories (NWT) ecosystems, its people and animal populations at risk due to accelerated warming, permafrost thaw, and changing precipitation regimes. As the NWT continues to warm, at disproportionately higher rates when compared to the rest of Canada, threats to the stability of NWT’s ecosystems are expected to increase. Consequently, understanding how climate warming has changed historically and its implications on natural ecosystems requires point-to-region-specific, long-term climatic data to elucidate important drivers of observed changes relevant to decision makers at community, Indigenous, Territorial and Federal government levels. However, in situ climate data are …

Unmanned Aircraft Systems For Precision Meteorology: An Analysis Of Gnss Position Measurement Error And Embedded Sensor Development, Karla S. Ladino

Theses and Dissertations--Biosystems and Agricultural Engineering

The overarching objective of this research was to enhance our comprehension of the three-dimensional precision of meteorological measurements obtained using small unmanned aircraft systems (UAS). Two complimentary experiments were conducted to achieve this objective.

The first experiment entailed the development and implementation of a system to determine the global navigation satellite system (GNSS) position accuracy on a UAS platform. This system was utilized to assess the static and dynamic accuracy of L1 and L1/L2 GNSS receivers in real-time kinematic (RTK) and non-RTK fix modes. Adjusted two-sample t-tests revealed significant differences in horizontal and vertical error between RTK and non-RTK receivers …

Estimation Of Economic Risk From Coastal Natural Hazards In Louisiana, Rubayet Bin Mostafiz

LSU Doctoral Dissertations

Louisiana, U.S.A., is among the most vulnerable areas globally to coastal natural hazards, with risk vulnerability likely increasing. The risks associated with non-tropical-cyclone hazards in Louisiana’s coastal zone have been understudied. This research enhances present and future (i.e., 2050) Louisiana risk assessment using locally-weighted, model-based hazard frequency/intensity and population projections.

Results suggest that property risks associated with extreme cold temperature and tornado are and will remain costlier than those for hail and lightning. Property risks of extreme cold temperature and hail are projected to decrease with the expected warming temperatures, with those of all four of these hazards peaking in …

Polarimetric Radar And Vhf Lightning Observations In A Significantly Tornadic Supercell, Jacob Bruss

The Journal of Purdue Undergraduate Research

No abstract provided.

Defining Viable Solar Resource Locations In The Southeast United States Using The Satellite-Based Glass Product, Jolie Kavanagh

Theses and Dissertations

This research uses satellite data and the moment statistics to determine if solar farms can be placed in the Southeast US. From 2001-2019, the data are analyzed in reference to the Southwest US, where solar farms are located. The clean energy need is becoming more common; therefore, more locations than arid environments must be observed. The Southeast US is the main location of interest due to the warm, moist environment throughout the year. This research uses the Global Land Surface Satellite (GLASS) photosynthetically active radiation product (PAR) to determine viable locations for solar panels. A probability density function (PDF) along …

An Investigation Of Geostationary Satellite Imagery To Compare Developing And Non-Developing African Easterly Waves, Jenna Bartlett

Theses and Dissertations

African easterly waves (AEWs) are known precursors to tropical cyclone (TC) formation, although it is not always clear which AEWs will develop and which AEWs will not. To investigate AEW evolution, this study examines novel observations from the geostationary Advanced Baseline Imager (ABI) during July-September 2019. Case studies are conducted for two AEWs: one that became Hurricane Dorian, the strongest and most devastating hurricane of the 2019 Atlantic hurricane season, and a long-lived September AEW that did not become a TC. Lower-level moisture and flow, and the strength and spatial distribution of convective activity, differed between these two waves. By …

Impacts Of Physical Parameterization Schemes And Soil Moisture Initialization On Boundary Layer Evolution In The Weather Research And Forecasting (Wrf) Model, Grace Cutting

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

Numerical weather prediction (NWP) models have become a necessary addition to the atmospheric research community over the last several decades, and atmospheric modeling has been used internationally for numerous operational and research purposes. NWP models contain a vast number of combinations of physical and dynamical parameterization schemes; however, they are not always accurate in forecasting weather phenomena at a particular location, as different combinations of parameterization schemes represent differing conditions. Weather Research and Forecasting (WRF) model simulations were run to explore which of the commonly used planetary boundary layer (PBL) schemes best represented upper-air data (as well as PBL evolution) …

Using Remote And In Situ Observations From Torus To Investigate A Preexisting Airmass Boundary And Its Influence On A Tornadic Supercell On 28 May 2019, Kristen Axon

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

During the 2019 field phase of Targeted Observation by Radars and UAS of Supercells (TORUS), a preexisting airmass boundary was sampled on 28 May 2019 in north-central Kansas in close proximity to a tornadic supercell. This work hypothesized that the preexisting airmass boundary was associated with a mesoscale air mass with high theta-E (MAHTE) that favorably interacted with the tornadic supercell to increase the likelihood of tornadogenesis. Observations from TORUS including mobile mesonets, unoccupied aerial vehicles, soundings, and ground-based mobile radar were used along with GOES-16 visible satellite imagery, Kansas mesonet surface stations, and KUEX WSR-88D data to investigate this …

A Numerical Investigation Of Tornado Production And Intensification In Tropical Cyclones, Marco Paredes

FIU Electronic Theses and Dissertations

The environmental conditions required for tornado formation and development in tropical cyclones (TCs) and the mechanisms underlying the intensification of TC tornadoes remain poorly understood. Previous research has suggested that low and mid-level dry air intrusion in TCs may enhance convective instability and influence the production of tornadoes. However, observations have their limitations in answering some of the key questions regarding the relationship among thermodynamic instability, dry air, and TC tornado genesis, development, and dissipation. In this study, a multiple nested Weather Research and Forecasting (WRF) model in a hindcasting mode is used to simulate Hurricane Ivan (2004) by resolving …

Climatology Of Rainfall Distribution And Asymmetries Of Tropical Cyclones: A Global Perspective, Oscar Guzman Rey

FIU Electronic Theses and Dissertations

Estimating the magnitude of tropical cyclone (TC) rainfall at different landfalling states is an important aspect of the TC forecast that directly affects the level of response from emergency managers in coastal areas. This research analyses the spatial distribution of the rainfall magnitude in tropical cyclones (TCs) at different stages over global oceans. The research’s central hypothesis is that TC rainfall exhibits distinct features in the long-term satellite dataset due to the evolution of the spatial distribution, radial variation, and asymmetries at the stages before, during, and after landfall. The resulting patterns are analyzed through a statistical approach that takes …

Understanding Coastal And Inland Hydrometeorological Hazards Produced By Extratropical And Tropical Cyclones Along The East Coast Of The United States, Katherine Towey

Dissertations, Theses, and Capstone Projects

As global temperatures continue to rise, the effects of anthropogenic climate change will impact the magnitude and frequency of pluvial, fluvial, and coastal flooding events. If we want to accurately predict changes in these flooding events, we need to fully understand them in the current climate. As such, this research examines the relationship between hydrometeorological hazards and the characteristics of the storm types, such as extratropical cyclones (ETCs) and tropical cyclones (TCs), that produce such hazards. Through the use of observational and reanalysis data, the work herein utilizes a cyclone-hazard association algorithm and extreme value analysis to assess the extent, …

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 …

Impact Of Climate Oscillations/Indices On Hydrological Variables In The Mississippi River Valley Alluvial Aquifer., Meena Raju

Theses and Dissertations

The Mississippi River Valley Alluvial Aquifer (MRVAA) is one of the most productive agricultural regions in the United States. The main objectives of this research are to identify long term trends and change points in hydrological variables (streamflow and rainfall), to assess the relationship between hydrological variables, and to evaluate the influence of global climate indices on hydrological variables. Non-parametric tests, MMK and Pettitt’s tests were used to analyze trend and change points. PCC and Streamflow elasticity analysis were used to analyze the relationship between streamflow and rainfall and the sensitivity of streamflow to rainfall changes. PCC and MLR analysis …

X-Band Phased-Array Weather-Radar Polarimetry Testbed, William Heberling Iv

Doctoral Dissertations

Phased-array weather radar have potential to replace reflector dish radar in major weather radar networks such as NEXRAD, providing faster update times and greater scan flexibility. However, the use of electronic scanning introduces polarization errors on weather radar measurables, requiring polarimetric bias calibration. The sources of polarimetric bias have been described theoretically, but experimental verification is still limited. Additionally, no standard method of calibration for polarimetric bias exists for phased-arrays. Therefore, the University of Massachusetts Amherst (UMass) presents a fully operational X-Band phased-array weather radar polarimetric testbed. The testbed evaluates the calibration of a planar dual-polarization X-band phased-array radar through …

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 …

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

Undergraduate Honors 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 …

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 …

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 …

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

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

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 …

Physical Investigation Of Downburst Winds And Applicability To Full Scale Events, Federico Canepa

Electronic Thesis and Dissertation Repository

Thunderstorm winds, i.e. downbursts, are cold descending currents originating from cumulonimbus clouds which, upon the impingement on the ground, spread radially with high intensities. The downdraft phase of the storm and the subsequent radial outflow that is formed can cause major issues for aviation and immense damages to ground-mounted structures. Thunderstorm winds present characteristics completely different from the stationary Gaussian synoptic winds, which largely affect the mid-latitude areas of the globe in the form of extra-tropical cyclones. Downbursts are very localized winds in both space and time. It follows that their statistical investigation, by means of classical full scale anemometric …

Connections Between Atmospheric Blocking, General Circulation, And Weather Extremes In A Hierarchy Of Models And Various Climates, Veeshan Narinesingh

Dissertations, Theses, and Capstone Projects

The field of geophysical fluid dynamics (GFD) includes the study of both the motion and thermodynamic aspects of the atmosphere. These properties are of particular importance because they directly influence both local and large-scale weather and climate and are associated with various phenomena. One phenomena that is particularly influential is atmospheric blocking. Atmospheric blocks are persistent, quasi-stationary anticyclones (a.k.a. high-pressure systems) that occur in the atmosphere and disrupt the flow. Blocks are known to induce heat extremes and cold spells, as well as steer storms and cause numerous types of hazards. Yet despite the hazards associated with blocks, our current …