Atmospheric Sciences Commons^™

Examining The Impact Of Stratospheric Vortex Variability On Us Surface Temperature, Elena M. Fernandez

Legacy Theses & Dissertations (2009 - 2024)

Variability in high-latitude stratospheric flow, including major sudden stratospheric warming (SSW) or strong polar vortex events, can modulate tropospheric circulation and have meteorological implications on surface temperature and weather. The largest tropospheric impacts from Northern Hemisphere stratospheric variability – and the regions of focus in the literature – are observed in the North Atlantic, Europe and Asia. Impacts on North America occur but have received less research attention. The goal of this thesis research is to identify and quantify the relationship between high-latitude stratospheric variability and North American wintertime temperature.Using the ERA-Interim and ERA-5 reanalysis for the period of 1999/2000–2018/19, …

A Comparative Analysis Of The Impact Of Low-Level Jets And Atmospheric Rivers In The Central U.S, Nabindra Gyawali

Legacy Theses & Dissertations (2009 - 2024)

Atmospheric Rivers (AR) are the primary source of poleward moisture transport globally. In theUnited States, much recent attention has been placed on Pacific Coast ARs which occur between December and March. However, the central US is also substantially impacted by warm-season AR. An open question is whether these warm-season ARs are synonymous with Great Plains low-level jets (LLJs) that have long served as a focal point of mesoscale atmospheric research. In this study, we perform a comparative analysis of ARs and LLJs in the central U.S using ECMWF’s climate-quality reanalysis of the 20th century, CERA-20C. The aim is to identify …

Changes In Large-Scale Extreme Precipitation In Over Taiwan And The Northeast United States : Past And Future, Lexi Henny

Legacy Theses & Dissertations (2009 - 2024)

Large-scale extreme precipitation over (1) the mid-Atlantic and Northeast United States and (2) Taiwan is attributed to weather types such as atmospheric river (AR), TC, and extreme integrated vapor transport (IVT). Statistically significant increases in season-total EP day precipitation are seen at many GHCN stations in winter, summer, and fall in the mid-Atlantic and Northeast region, and at certain high-elevation grid points in Taiwan Mei-yu season. During the cold season of winter and spring, the U.S.-based changes come from AR-associated EP days and are associated with strengthened southwesterly winds and IVT either within EP days, in the season mean, or …

Long-Term Trends And Variability Of Pm₂.₅ Mass, Chemical Components, And Sources Over Nys, Hesham Abdelmonem Hassan

Legacy Theses & Dissertations (2009 - 2024)

Eighteen years of ambient PM2.5 mass and major components are used in this study to harmonize the carbonaceous fraction of PM2.5 data, and to examine long-term trends and seasonal variability changes. The major decreasing trend of PM2.5 mass and major inorganic ions reflects the ambient concentration response to clean air regulations and policies.Although elemental carbon shows a decreasing trend in agreement with most other PM2.5 components, organic carbon shows a different behavior of no-trend to slightly increasing trend in some sites. Organic carbon behavior indicates the growing role of non-combustion sources at the expense of decreasing combustion sources. Seasonal trends …

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 …

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 …

Dynamic Impacts Of Hadley Circulation On Saharan Desert Warming Amplification, Alejandro Manuel Ayala

Legacy Theses & Dissertations (2009 - 2024)

Changes in temperature due to climate change are not spatially uniform, and deserts and other drylands, which are greatly underrepresented in climate studies, are warming at a much faster rate than much of the globe with increasing concentrations of greenhouse gases. This strong warming amplification over deserts, termed Desert Amplification (DA), is most pronounced over the world’s largest and driest Sahara Desert and the Arabian Peninsula. The Sahara and Arabian deserts are formed in the subtropical subsiding branch of the Hadley Circulation (HC) and so the changes in large-scale subsidence associated with adiabatic heating could impact the DA dynamically. While …

Spatiotemporal Variability Of Snow Depth On Arctic Sea Ice In Cmip6 Models And Satellite Data, Shengzhe Chen

Legacy Theses & Dissertations (2009 - 2024)

The Arctic has experienced rapid environmental changes in recent decades. Motivated by the important role of snow over sea ice in influencing Arctic climate variability and change, this dissertation aims to improve our knowledge of spatiotemporal variability of snow depth and processes over Arctic sea ice in the observations and model simulations.First, we evaluate snow depth over Arctic sea ice during 1993–2014 simulated by the models from the Coupled Model Intercomparison Project phase 6 (CMIP6) against recent satellite retrievals. The CMIP6 models capture some aspects of the observed snow depth climatology and variability. The observed variability lies in the middle …

Understanding Changes In Precipitation, Wildfires, And Possible Governing Factors Over Central Equatorial Africa, Yan Jiang

Legacy Theses & Dissertations (2009 - 2024)

Tropical rainforests are global epicenters of biodiversity and modulators of climate. A long-term drying trend has occurred in the Congo Basin since the 1980s and this raises great concerns for sustaining the Congolese rainforest and local rain-fed agriculture. Motivated by documented rainfall changes and the need to improve understanding of main factors influencing precipitation variability and changes in Central Equatorial Africa (CEA), this dissertation conducts synthesized studies on 1) quantifying variations in precipitation seasonality by focusing on dry season duration, 2) estimating cascading wildfire risks associated with changes in precipitation patterns, and estimating impacts of 3) the tropical Indian Ocean …

The Mountain Gap Wind Of The Isthmus Of Tehuantepec And Its Impact On Tropical Cyclogenesis In The Eastern Pacific, Adolfo Lugo Rios

Legacy Theses & Dissertations (2009 - 2024)

In this dissertation we research two aspects of the mountain gap wind northerlies of the Isthmus of Tehuantepec in Southern Mexico. The causes of extreme gap wind northerlies, emphasizing the causes by tropical weather systems, like easterly waves troughs or hurricanes, and the impacts of an extreme gap wind events on tropical cyclogenesis.Through the use of an index to diagnose the mountain gap wind strength, its evolution through the year and the mechanisms leading to extreme mountain gap winds was highlighted. The index revealed that the gap wind is strongly related to high surface pressure anomalies over the GoM throughout …

A Synoptic-Dynamic Analysis Of The Structure And Evolution Of Persistent North Pacific Wintertime Ridge Regimes, Tyler Christopher Leicht

Legacy Theses & Dissertations (2009 - 2024)

Along the west coast of North America (NA), a majority of the precipitation for the entire year falls during winter as a result of approximately a dozen cyclones or atmospheric rivers. However, persistent upper-level ridges can prevent the occurrence of wintertime precipitation events and lead to extended drought, significant water shortages, and adverse economy-wide impacts for major population centers in California. An increased understanding of the dynamical and thermodynamical processes that govern upper-level ridge formation, persistence, and dissipation during the rainy season along western NA would allow decision makers to better manage water resources and motivates this thesis. Persistent upper-level …

The Surface Heating Efficiency Of Atmospheric Energy Flux Events During Arctic Winter, Christopher Joseph Cardinale

Legacy Theses & Dissertations (2009 - 2024)

The flux of moist static energy (MSE) into the polar regions plays a key role in the energy budget and climate of the polar regions. While usually studied from a vertically integrated perspective (Fwall), this dissertation examines its vertical structure, using the NASA-MERRA-2 reanalysis to compute climatological and anomalous fluxes of sensible, latent, and potential energy across 70◦N and 65◦S. This dissertation applies an energy budget analysis to winter-season synoptic periods of increased tropospheric (Ftrop) and stratospheric (Fstrat) energy flux convergence events and examines the processes that drive Arctic anoma lous surface warming and sea ice loss during Ftrop events. …

New York City Micronet : Comprehensive Site Metadata And Classifications And Characteristics Of The Urban Heat Island, Ashley Williamson

Legacy Theses & Dissertations (2009 - 2024)

The New York City Micronet (NYC Micronet), comprised of 17 stations, was installed in the Fall of 2020 for the purpose of long-term monitoring of climate change, and to provide support to utility operations for Consolidated Edison, Inc. (Con Edison). There are five additional standard NYS Mesonet stations located in NYC installed in late 2017. Co-located at the standard stations are three flux, and three profiler stations from sub-networks within the NYS Mesonet. With 22 different locations collecting 5-minute averaged data, this network becomes the highest spatial and temporal resolution urban meteorological network (UMN) of this quality in NYC. This …

The Mountain Gap Wind Of The Isthmus Of Tehuantepec And Its Impact On Tropical Cyclogenesis In The Eastern Pacific, Adolfo Lugo Rios

Atmospheric and Environmental Sciences Theses and Dissertations

In this dissertation we research two aspects of the mountain gap wind northerlies of the Isthmus of Tehuantepec in Southern Mexico. The causes of extreme gap wind northerlies, emphasizing the causes by tropical weather systems, like easterly waves troughs or hurricanes, and the impacts of an extreme gap wind events on tropical cyclogenesis.

Through the use of an index to diagnose the mountain gap wind strength, its evolution through the year and the mechanisms leading to extreme mountain gap winds was highlighted. The index revealed that the gap wind is strongly related to high surface pressure anomalies over the GoM …

The Urban Heat Island Of Bengaluru, India : Characteristics, Trends, And Mechanisms, Heather Samantha Sussman

Legacy Theses & Dissertations (2009 - 2024)

The urban heat island (UHI) effect refers to how urban surfaces tend to be warmer than nearby non-urban areas due to less vegetation and other processes. UHIs can increase the risk of heat and respiratory illnesses. Since every city is unique, UHIs should be studied on a local-scale. One particular city that has not had its UHI comprehensively evaluated is Bengaluru, India. Bengaluru was once known as the “Garden City” of India due to a wide presence of gardens and public parks, but is now known as the “Silicon City” of India due to the overwhelming presence of the information …

The Impacts Of Transported Wildfire Smoke Aerosol On Surface Air Quality In New York State, Wei-Ting Hung

Legacy Theses & Dissertations (2009 - 2024)

In New York State (NYS), summertime long-range transported smoke plumes and high fine mode particulate matter (PM2.5) concentration during the smoke episodes have been reported. Since the frequency, intensity, and burned area of wildfires over Northern America have increased in recent years, the contribution of transported smoke aerosols to local air quality could become more significant. This study aimed to characterize the transport of smoke aerosols and quantify their impacts on the local air quality over NYS. A case study of a transported smoke event in mid-August of 2018 and multi-year analysis of the smoke cases during the summer seasons …

The Contributions Of Dynamical And Diabatic Processes Preceding And Accompanying Major Greenland Ice-Melt Events, Scott Feldman

Legacy Theses & Dissertations (2009 - 2024)

Extratropical cyclones and/or short-wave disturbances can reinforce Greenland blocking through upper-level flow amplification and can increase poleward heat and moisture transport into the Arctic. Increased poleward heat and moisture transport into the Arctic may enhance Greenland ice melt during the spring, summer, and fall months. The need to better understand the underlying dynamical and diabatic processes that may contribute to Greenland ice melt motivates this thesis. The purpose of this thesis is to investigate: 1) the role of advective warming due to poleward heat and moisture transport into the Arctic in facilitating Greenland ice melt, 2) the role of adiabatic …

It Takes Two To Tango : Understanding The Processes That Lead To Simultaneous Changes In Tropical Cyclone Intensity And Size And Communicating The Associated Hazards To Emergency Managers, Emily A. Paltz

Legacy Theses & Dissertations (2009 - 2024)

The severity of tropical cyclone (TC) hazards is modulated by both TC intensity and size. More intense TCs produce stronger storm surges and increase wind damage. Larger TCs potentially impact more people, increase the duration of TC hazards, produce stronger storm surges and increase the amount of rainfall and flooding. Thus, accurately forecasting both TC intensity and size and effectively communicating those forecasts are critical to properly preparing communities for TC impacts. Forecast accuracy can be improved by enhancing our understanding about the processes that cause changes in TC intensity and size. This research divides the Extended Best Track dataset …

Exploring Environmental And Methodological Sensitivities Of Forecasted And Observed Surface Winds And Gusts Using Underutilized Datasets, Alex Roslyn Gallagher

Legacy Theses & Dissertations (2009 - 2024)

Accurate forecasts and reliable observations of surface mean winds and gusts inhabit a vast and essential role in meteorological applications that range from wind energy, atmospheric transport, fire weather, and hazard assessment. This dissertation aims to address and explore known shortfalls in the prediction of mean winds and gusts as well as enhance evaluation and understanding of observed surface wind measurements. A variety of forecasts, methodologies, and observational dataset, many of which have been previously un- or under-utilized, are leveraged to tackle the differing needs of assessing mean winds, gusts, and the surface environment.Detailed verifications of HRRR (version 3 and …

Theoretical And Observational Analysis Of Ice Particles For Improvement Of Ice Microphysical Models, Vanessa Przybylo

Legacy Theses & Dissertations (2009 - 2024)

Frozen hydrometeors can grow to acquire a multitude of shapes and sizes, which influence the distribution of mass within cloud systems. Aggregates have a variety of formations based on initial ice particle size, shape, falling orientation, and the number of particles that collect. This work employs the theoretical Ice Particle and Aggregate Simulator (IPAS) as a statistical tool to repetitively collect ice crystals to derive bulk aggregate characteristics.

Objective Methodology To Identify The Sea Breeze Circulation And Associated Low-Level Jet In The New York Bight, Elizabeth J. Mccabe

Legacy Theses & Dissertations (2009 - 2024)

While the sea breeze has been studied for decades, in a complicated mid-latitude coastal region such as the New York Bight (NYB), the general thermodynamic structure and dynamics of the circulation is poorly characterized. The East Coast of the United States has become a critical area for offshore wind farm development, including a generally favorable wind resource, relatively shallow waters on an extensive continental shelf, frequent warm season sea breezes, and proximity to large populated areas. Thus the sea breeze will play a key role in the new energy economy, given the favorable wind speeds and capacity factors during periods …

A Mechanism For Upscale Growth Of Convection In The Complex Terrain Of The Northeast U.S, Brennan Joseph Stutsrim

Legacy Theses & Dissertations (2009 - 2024)

Upstate New York has a variety of complex terrain that can interact with the background flow to create mesoscale heterogeneities in the lower troposphere. The major valleys of Upstate New York, the Hudson and Mohawk Valleys, often have increased moisture content and stronger surface winds than the higher terrain surrounding them. These features can have a profound effect on the evolution of convective storms, especially in cases characterized by low-to-moderate shear, which tends to favor pulse-like or multicellular convection. Analysis of composite radar imagery has indicated that convective storms often change mode while descending from the Catskills Mountains into the …

Predictability Issues Associated With Near-Freezing Precipitation Type In Complex Terrain, Matthew Seymour

Legacy Theses & Dissertations (2009 - 2024)

Predictability challenges are heightened in winter weather forecasting when the environment for high-impact weather is marginal or varies over short distances. High-resolution numerical weather prediction (NWP), such as the High-Resolution Rapid Refresh (HRRR), and ensemble forecast systems, such as the Global Ensemble Forecast System (GEFS), are useful for constraining forecasts. However, their use can be challenging in marginal, near-freezing, situations when precipitation type is uncertain. Uncertainties in planetary boundary layer (PBL) and microphysics (MP) parameterizations and subtle synoptic-scale model errors brought on by differences in initial and lateral boundary conditions (IC/BCs) complicate the p-type forecast. Further, complex terrain, such as …

The Effect Of Differential Friction On Tropical Cyclone Development Close To Land, Minghao Zhou

Legacy Theses & Dissertations (2009 - 2024)

Hurricane Karl (2010) underwent unexpected rapid intensification in the Bay of Campeche while remaining in close proximity (within 150 km) to land. It is hypothesized that the frictionally-enhanced inflow contributed positively to this evolution, despite reduced surface fluxes and increased momentum loss over land. In this study, the role of differential friction in the development of a tropical cyclone (TC) tracking parallel to a coastline is examined based on this prototype.A series of high-resolution, semi-idealized numerical simulations with full physics were conducted on a β-plane with curvature effects of the Earth. After initializing a TC from a synoptic-scale thermal perturbation, …

Seasonal Differences In The Impacts Of Ipo And Amo On Temperature And Precipitation Over South America, Thomas Favata

Legacy Theses & Dissertations (2009 - 2024)

The Atlantic Multidecadal Oscillation (AMO) and Interdecadal Pacific Oscillation (IPO) have been shown to impact temperature and precipitation across the globe. However, the seasonal differences in their impacts are not well studied. This study analyzes the seasonal differences in the impacts of the AMO and IPO on South American temperature and precipitation. Observational and reanalysis data with enough temporal coverage to isolate the multidecadal modes were used first to identify the regions impacted by the AMO and IPO through a correlation analysis. Then Empirical Orthogonal Functions (EOF) and a Maximum Covariance Analysis (MCA) were used to determine the seasonal spatial …

Diagnosing High Sinuosity Regimes Associated With Anomalous Greenland Ice-Melt Events Using Self-Organizing Maps, Mansour El Riachy

Legacy Theses & Dissertations (2009 - 2024)

Sinuosity, a metric that describes the waviness of the circumpolar flow, is adapted to quantify modification of the tropospheric polar vortex within longitudinal sectors by localized incursions of warm, moist air from middle latitudes associated with Arctic cyclones (ACs). In this thesis, we identify four corridors of high AC track frequency, on which we center 90° longitudinal sectors comprising the following regions: Pacific, West of Greenland, Atlantic, and Asian. Sectorial sinuosity is calculated for the West of Greenland sector and is used to quantify the amplitude of the 300-hPa flow associated with anomalous Greenland ice-melt events.

On The Structure And Phase Speeds Of The Kelvin Waves And Mjo Over The Indian Ocean, Ahmed Shaaban

Legacy Theses & Dissertations (2009 - 2024)

Kelvin waves in the stratosphere are well known to behave as radiative gravity waves. Yet, the tropospheric component of these Kelvin waves (and other tropical modes) has often been described as superpositions between the baroclinic modes. By decomposing the Kelvin waves into upward and downward-phase components, we found that only upward-phase Kelvin waves occupy the troposphere, indicating that the tropospheric Kelvin waves are not vertical standing oscillations as previously thought. Fast Kelvin waves were found to obey the structure of radiating gravity waves, like their stratospheric counterpart, more than the moist waves. The unexpected lack of variation in vertical tilt …

Seasonal Variations And Long-Term Trend Of Mineral Dust And The Effects Of Dust On Cloud And Precipitations, Yanda Zhang

Legacy Theses & Dissertations (2009 - 2024)

For its enormous emission rate and long-range transport ability, mineral dust is one of the most abundant aerosol species, contributing to about half of the global atmospheric aerosol dry mass burden. A series of studies demonstrated the significant influences of mineral dust on air quality, public health, biogeochemical cycles, and climate systems. In the atmosphere, mineral dust is known to have important impacts on the Earth system through direct effects (scattering and absorbing shortwave and longwave radiations), semi-direct effects (changing atmospheric temperature structure and cloud lifetime), and indirect effects (influencing cloud microphysics processes as cloud condensation nuclei (CCN) and ice-nucleating …

Land-Atmosphere-Cloud Interaction : Sensitivity Of Weather Forecast Models To Complex Land Surface Conditions In New York State, Lanxi Min

Legacy Theses & Dissertations (2009 - 2024)

The land-atmosphere coupling system is important for the simulation of key quantities like surface temperature, precipitation, and radiative energy. Over the complex terrain of New York State, the land-atmosphere coupling process is quite complex and misrepresenting the coupling processes could lead to strong biases. Evaluating the weather forecasting models is vital for enhancing understanding of physical and processes and further improving the model forecasting. A comprehensive observation network, the New York State Mesonet (NYSM) provides a great opportunity to investigate how the land atmosphere coupling process are simulated over complex terrain region. This research includes three components. In first part, …

The Role Of Ammonia In Atmospheric New Particle Formation And Implications For Cloud Condensation Nuclei, Arshad Arjunan Nair

Legacy Theses & Dissertations (2009 - 2024)

Atmospheric ammonia has received recent attention due to (a) its increasing trend across various regions of the globe; (b) the associated direct and indirect (through PM2.5) effects on human health, the ecosystem, and climate; and (c) recent evidence of its role in significantly enhancing atmospheric new particle formation (NPF or nucleation) rates. The mechanisms behind nucleation in the atmosphere are not fully understood, although over the last decade there have been significant developments in our understanding. This dissertation aims at improving our understanding of atmospheric ammonia in the atmosphere, its spatiotemporal variability, its role in atmospheric new particle formation, and …