Atmospheric Sciences Commons^™

Gravity Wave Drag Parameterizations For Earth’S Atmosphere, Christopher J. Heale, Christopher G. Kruse, Jadwiga H. Richter, M. Joan Alexander, Julio T. Bacmeister, Junhong Wei

Publications

Atmospheric gravity waves (GWs), or buoyancy waves, transport momentum and energy through Earth’s atmosphere. GWs are important at nearly all levels of the atmosphere, though, the momentum they transport is particularly important in general circulation of the middle and upper atmosphere. Primary sources of atmospheric GWs are flow over mountains, moist convection, and imbalances in jet/frontal systems. Secondary GWs can also be generated as a result of dissipation of a primary GWs. Gravity waves typically have horizontal wavelengths of 10’s to 100’s of kilometers, though, they can have scales of 1’s to 1000’s of kilometers as well. Current effective resolutions …

Droughtscape, Winter 2023, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Winter 2023

An Exploration Of Cloud Droplet Growth By Condensation And Collision-Coalescence In A Convection-Cloud Chamber, Jacob T. Kuntzleman

Dissertations, Master's Theses and Master's Reports

Atmospheric clouds are crucial to weather and climate, and the rate at which droplets collide and coalesce to form precipitation is one of the fundamental controlling processes. The convection-cloud chamber allows the interactions between aerosols and cloud droplets produced by condensation to be investigated within a turbulent environment. Studying the full range of microphysical conditions in atmospheric clouds is not possible, however, unless conditions for droplet growth by collision and coalescence are also achieved. In this study, we explore the conditions favorable to collision-coalescence growth in convection-cloud chambers, extending previous work on steady-state droplet size distributions due to condensation alone. …

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 …

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 Behavior Of Partially Coherent Twisted Space-Time Beams In Atmospheric Turbulence, Milo W. Hyde Iv

Faculty Publications

We study how atmospheric turbulence affects twisted space-time beams, which are non-stationary random optical fields whose space and time dimensions are coupled with a stochastic twist. Applying the extended Huygens–Fresnel principle, we derive the mutual coherence function of a twisted space-time beam after propagating a distance z through atmospheric turbulence of arbitrary strength. We specialize the result to derive the ensemble-averaged irradiance and discuss how turbulence affects the beam’s spatial size, pulse width, and space-time twist. Lastly, we generate, in simulation, twisted space-time beam field realizations and propagate them through atmospheric phase screens to validate our analysis.

Stratospheric Glider Measurements Of Atmospheric Parameters, Anisa Haghighi

Theses and Dissertations--Mechanical and Aerospace Engineering

In June 2021 a series of high altitude flights were conducted in Spaceport America, NM, using a balloon launched Uncrewed Aircraft System (UAS) to assess its capability to conduct measurements of various atmospheric properties and study turbulence in the troposphere and lower stratosphere. This UAS descends using an automated flight trajectory. The instruments aboard included a NASA-developed infrasonic microphone to evaluate its remote turbulence detection capabilities and a five-hole probe capable of measuring the in situ wind vector. Also on board were temperature, humidity and wind profile sensors. This document focuses on the atmospheric properties measured at high altitudes, the …

Precision Meteorological Prediction Employing A Data-Driven, Adaptive, Real-Time (Dart) Approach, Sujit Sinha

Theses and Dissertations--Mechanical and Aerospace Engineering

The objective of this research is to improve precision meteorological prediction, benefiting both uncrewed aerial vehicle (UAV) operations by avoiding hazardous flight conditions and tracking contaminant or toxic clouds caused by incidents, accidents, or fires. The operational concept is to collect meteorological observations from instruments mounted on a swarm of UAVs, telemeter the data to a weather simulation model, revise the predicted solution by adapting the flow field to the observations, and then transmit the updated forecast to appropriate personnel as well as to the guidance system of UAVs for repositioning to the next set of most beneficial measurements. While …

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 …

Shallow Water Coral Distribution And Its Response To Climate Change, Amaury De Jesus

Dissertations and Theses

Shallow water corals are one of the main reef-building organisms that secrete carbonates as their skeletons, and therefore, are one of the major sinks of CO2 in the ocean. These reef builders are also very crucial to marine environments and human society. As the global energy demand continues rising, fossil fuel burning increases at a faster pace despite the increase in energy supply using clean and renewable energy. The increase of CO2 in the atmosphere has been shown to exacerbate global warming and may cause ocean acidification, threatening the habitat of shallow-water corals. Many recent observations show alarming signs of …

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 …

Physical, Optical, And Chemical Properties Of Light Absorbing Aerosols And Their Climatic Impacts, Susan Mathai

Dissertations, Master's Theses and Master's Reports

Aerosols are particles suspended in the atmosphere; they are emitted during natural phenomena such as dust storms, wildfires, and volcanic eruptions, and during anthropogenic activities like household wood burning, vehicles operations, and industrial productions, or they can form in the atmosphere from gas to particle partition. Aerosols impact earth’s weather and climate by absorbing and scattering the incoming solar and the outgoing earth thermal radiation and interacting with clouds. The optical properties of aerosols evolve as the chemical and physical properties vary during their residence in the atmosphere. In addition, the aerosols’ properties strongly depend on the vertical distribution in …

Large Cloud Droplets And The Initiation Of Ice By Pressure Fluctuations: Molecular Simulations And Airborne In-Situ Observations, Elise Rosky

Dissertations, Master's Theses and Master's Reports

From the molecular dynamics of water molecules to the global processes that control atmospheric circulation: describing the evolution of atmospheric clouds necessitates physics that spans vast spatial scales. In this work, steps are taken towards connecting the molecular physics of ice-nucleation to the growth and subsequent freezing of cloud droplets in convective cumulus clouds. Motivated by experimental evidence of ice nucleation triggered by agitation and distortion of a water droplet surface, the first study in this dissertation uses molecular dynamics simulations to demonstrate that negative Laplace pressure from a curved water surface leads to heterogeneous ice nucleation at higher temperatures. …

Perceived Barriers To Cervical Cancer Screening Among Hispanic Women, Damaris Perez

Walden Dissertations and Doctoral Studies

AbstractHispanic women are among the ethnic groups with higher cervical cancer rates in the United States. This mixed-method study was conducted to explore perceived barriers and self-efficacy-related factors to cervical cancer screening in foreign-born Hispanic women in Florida. The theory of planned behavior was applied to determine if behavioral intentions influence access to cervical cancer screening. The inclusion criteria included Hispanic women 18 years old and older without a hysterectomy history. Quantitative data were collected through a self-administered survey. A total of 84 individuals completed the survey. A binary logistic regression analysis was performed to determine if sociodemographic factors are …