Oceanography and Atmospheric Sciences and Meteorology Commons^™

Using Stochastic Physics Perturbations In Ensemble Forecasts To Investigate Predictability Of Mesoscale Winter Precipitation Events, William Massey Bartolini

Legacy Theses & Dissertations (2009 - 2024)

Accurate winter precipitation forecasts are difficult due to factors influencing precipitation amounts and precipitation types including numerical weather prediction biases. In particular, large forecast errors can arise due to uncertainties in parameterized processes, especially those related to microphysics and turbulence. Many winter weather impacts are due to mesoscale precipitation features that are better represented in convection-permitting model forecasts. One way to account for model physics uncertainty is to design convection-permitting ensembles using stochastic physics methods. For example, stochastic parameter perturbation (SPP) varies parameters within individual schemes. SPP methods can be combined with varied initial and boundary conditions (ICs/BCs) to represent …

Enhancing The Impact Of Infrared Satellite Observations On Data Assimilation Through Aerosol-Aware Framework, Shih-Wei Wei

Legacy Theses & Dissertations (2009 - 2024)

Aerosol radiative effects, both direct and indirect, have been extensively studied in climate projection and numerical weather prediction. However, the aerosol impacts on radiance in the context of data assimilation (DA) have received less research attention. In modern DA systems, thermal infrared (IR) radiance observations have been extensively assimilated since the mid-1990s. Prior studies have shown pronounced reduction of brightness temperature (BT) at the IR window region due to the presence of aerosols. Despite its effects on IR radiance, aerosol information is not considered in most DA systems.Without considering the aerosol impacts on radiance, the representation errors arise from the …

The Impacts Of Atlantic And Pacific Sea Surface Temperature Variability On South American And Arctic Climate, Zhaoxiangrui He

Legacy Theses & Dissertations (2009 - 2024)

Atlantic and Pacific sea surface temperature (SST) variations mainly include El Niño–Southern Oscillation (ENSO) on interannual timescales and Pacific multidecadal variability (PMV) and Atlantic multidecadal variability (AMV) on decadal-interdecadal timescales. Understanding their impacts on South American and Arctic climate is crucial for studying climate variability and helpful to constrain climate model projections for these regions on multidecadal timescales. Prior studies focused mainly on their impacts on global climate, but multidecadal impacts on South American climate are poorly understood due to the lack of long observational records. Furthermore, earlier research investigated primarily the isolated impacts on global climate from the Atlantic …

Assimilating New York State Mesonet Observations For A Summertime Convective Event, Hsiao-Chun Lin

Legacy Theses & Dissertations (2009 - 2024)

In New York State (NYS), the prediction of high-impact severe weather event has presented a challenging forecasting problem. The NYS Mesonet (NYSM) has the potential to improve the severe weather forecasting through its continuous in situ and remote sensing measurements on the lower troposphere. The dense observing network can capture the evolution of mesoscale motions with high temporal and spatial resolution. The objectives of this dissertation are (1) to assess whether the assimilation of NYSM observations into numerical weather prediction models could improve model analysis and short-term weather forecasting, and (2) to figure out the important key factor and physical …

Understanding Precipitation Dynamics Of Southern China Through Isotope Analysis Of Lake Yilong Sediments And Other Regional Records, Angelena N. Campisi

Legacy Theses & Dissertations (2009 - 2024)

The delivery of monsoonal precipitation in the face of climate change is a growing concern, especially within regions with high population density and a corresponding demand for freshwater resources. Within these regions, the monsoon season can deliver more than half of the annual freshwater for the area. Regional climate dynamics controlling these precipitation patterns within the Holocene (11.7 kyr BP−present) are poorly understood and difficult to differentiate within a single climate proxy from a single site. However, by cross referencing different proxies within a given region we can begin to discern general trends in precipitation dynamics on centennial and multi−centennial …

The Effects Of Ep And Cp Enso Phases During Different Seasons On The First Four Dominant Modes Of The Mjo, Suphanat Maneesai

Legacy Theses & Dissertations (2009 - 2024)

El Niño-Southern Oscillation (ENSO) is an interannual climate mode that is dominant in tropical Pacific and affects regional and global weather and climate. Some may categorize ENSO into two types – eastern Pacific ENSO (EP ENSO) and central Pacific ENSO (CP ENSO). Madden-Julian Oscillation (MJO) is the most dominant intraseasonal mode in the tropics that impacts regional and global weather. Previous studies have established relationships between ENSO and MJO. An empirical orthogonal function (EOF) analysis was performed to retrieve the principal components (PCs), instead of filtering atmospheric data, to approximately trace the MJO to analyze its relationship with ENSO. An …

The Simulated Sensitivity Of The North American Monsoon At Convection-Permitting Scales, Brendan Wallace

Legacy Theses & Dissertations (2009 - 2024)

The North American Monsoon (NAM) is a major contributor to annual rainfall for large portions of the North American Southwest. Much of the prior work examining the NAM using numerical models has been done at scales exceeding 20-km grid spacing. At these coarse scales, unresolved processes and poorly resolved geographic features can impact model performance. This can present a problem when simulating the NAM particularly with regard to orographic precipitation, precipitation on sub-daily timescales, and land surface-atmosphere interactions. This dissertation seeks to better understand the NAM through examination of several sets of convection-permitting regional climate model output. The primary goal …

Comparison Of 2018-2021 Tropical Cyclone Track Forecasts Before And After Noaa G-Iv Missions, Melissa Piper

Legacy Theses & Dissertations (2009 - 2024)

Tropical cyclone (TC) hazards are primarily dictated by the TC position; thus, it is important to produce accurate TC track forecasts. Many different features can influence a TC’s motion, yet these features are not always well sampled by in-situ observations over the open ocean, creating a need for supplemental observation collected via aircraft, including the deployment of dropsondes. In 1997, the National Hurricane Center (NHC) began operational synoptic surveillance missions in the near-storm environments of TCs using the Gulfstream IV-SP jet aircraft (G-IV), with the goal of reducing track forecast errors. In the first 10 years of operational missions, the …

Large-Scale Flow Patterns Conducive To Central American Extreme Precipitation Events During Autumn, Alexander Kyle Mitchell

Legacy Theses & Dissertations (2009 - 2024)

Extreme precipitation events (EPEs), characterized by daily widespread heavy rainfall exceeding the 95th percentile across Central America, can have large impacts on agriculture, life, and property during the rainy season. EPEs during the Northern Hemisphere (NH) autumn, however, have been observed to be influenced by both tropical and extratropical originating phenomena such as easterly waves and cold surges, respectively. Given the limited research in this area, the novelty of this work is to apply a systematic approach for identifying and better understanding EPEs, and investigating their associated synoptic-scale variability using daily high-resolution observations and reanalysis products over Central America. An …

A Composite Analysis Of Summer Afternoon Heavy Precipitation Events In The Taipei Basin Under Weak Synoptic Forcing And Pm2.5 Changes, Cidny Ramirez Martinez

Legacy Theses & Dissertations (2009 - 2024)

Taipei, Taiwan is a city affected by various types of precipitation. However, one of the most impactful short-term sources of precipitation is afternoon thunderstorms. Understanding the trends of these afternoon thunderstorms and the extent to which PM2.5 impacts precipitation totals is imperative for improving forecasting and developing urban infrastructure that can deal with said totals.

Probabilistic Forecasting Of Winter Mixed Precipitation Types In New York State Utilizing A Random Forest, Brian Chandler Filipiak

Legacy Theses & Dissertations (2009 - 2024)

Operational forecasters face a plethora of challenges when making a forecast; they must consider multiple data sources ranging from radar and satellites to surface and upper air observations, to numerical weather prediction output. Forecasts must be done in a limited window of time, which adds an additional layer of difficulty to the task. These challenges are exacerbated by winter mixed precipitation events where slight differences in thermodynamic profiles or changes in terrain create different precipitation types across small areas. In addition to being difficult to forecast, mixed precipitation events can have large-scale impacts on our society.

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 …