Atmospheric Sciences Commons^™

16-Day Free-Traveling Rossby Waves And Their Association With Northern Hemisphere Blocking, Ernesto W. Findlay

Legacy Theses & Dissertations (2009 - 2024)

An analysis of the 16-day free Rossby wave is performed. The behavior of this wave includes a barotropic vertical structure that is independent of local forcing. An Empirical Orthogonal Function (EOF) analysis was performed on 15–30-day filtered geopotential height anomalies to extract the spatial patterns of the wave. Results show that the first two EOFs are in quadrature with each other, representing a westward moving signal with an average period of around 23 days and a phase velocity of. The Principal Components (PCs) from these EOFs were used to construct a 16-day wave index, which was employed as a tool …

Extreme Molecular Diversity In Biomass Burning Atmospheric Organic Aerosol Observed Through Ultrahigh Resolution Mass Spectrometry, Matthew Brege

Dissertations, Master's Theses and Master's Reports

Ambient atmospheric aerosol is ubiquitous in the atmosphere, originating from a variety of natural and man-made sources. These microscopic particles have profound impacts on the global climate system as well as human health. The organic fraction of atmospheric aerosol is an extremely complex mixture which is not yet fully characterized. These unknown organic aerosol species contribute to the uncertainty in the effect of aerosol on climate and uncertainty in overall ambient aerosol toxicity. Light absorbing organic aerosol can interact with incoming solar radiation and contribute to atmospheric heating; however, the source apportionment and overall fate of these absorbing organic aerosol …

Spatial And Temporal Analysis Of The 27 April 2011 Tornado Outbreak In Central Alabama, Whitney Flynn, Tanveer Islam

Research, Publications & Creative Work

This study investigates the spatial and temporal patterns of the 27 April 2011 tornado outbreak in Central Alabama. Disasters, and vulnerabilities to such events, vary across space and time. The 2011 Super Outbreak was the largest, most costly, and one of the most deadly tornado outbreaks ever recorded in U.S. history. In this study, the results of 29 documented tornado tracks (889 data points total) in Central Alabama reveal findings related to complex topography and its effects on tornado intensity. The temporal pattern s of this particular outbreak are - consistent with other studies’ evidence that suggests a small peak …

Droughtscape, Winter 2019, National Drought Mitigation Center

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

Contents

From the Director

Drought intensified in California and Nevada, eased elsewhere

Year in Review: Drought spread and intensified in the West; record precipitation in the East

Drought impact summary for 4th quarter 2018

Drought impact summary 2018

Five states began drought plan updates in 2018

New web-based form makes submitting drought observations easier

FEMA risk assessment process tailored for drought

Upcoming events

Wake Vortex Pair Formation As An Analog For Dust Devil And Tornado Genesis, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

In 1966, meteorologist R.S. Scorer attempted to explain how large-scale oceanic tropical depressions become hurricanes or typhoons. His model was based on the idea that when these large-scale tropical depression structures begin to rotate, mostly due to Coriolis effects, an annular outer portion of that structure changes suddenly to a potential vortex segment, with the same outer radial limit as the low-pressure structure, but with an inner radius that conserves the overall system angular momentum and kinetic energy. By analogy with the "jump" instability describing sudden buckling of a vertical column, this paper shows that his conjecture merits additional consideration. …

Multi-Scale Interactions Between The Diurnal Cycle, The Mjo, And Convectively Coupled Equatorial Waves Over The Maritime Continent, Lakemariam Yohannes Worku

Dissertations

Given the Maritime Continent’s (MC’s) critical role in the global climate, examining variations in diurnal cycle and its interaction with the Madden–Julian Oscillation (MJO), Kelvin and Equatorial Rossby waves may lead to improved sub-seasonal forecasts. This study used satellite data of TRMM, TRMM Precipitation Features (PFs), and convective classifications from ISCCP. The convection becomes more organized through the afternoon and evening, leading to peak rainfall over the islands around 1800–2100 local standard time (LST). Over the next few hours, some of that rainfall transitions to stratiform rain over land. The convection then propagates offshore overnight with rainfall peaking along the …

Recent Trends In Stratospheric Chlorine From Very Short‐Lived Substances, Ryan Hossaini, Elliot Atlas, Sandip S. Dhomse, Martyn P. Chipperfield, Peter F. Bernath, Anton M. Fernando, Jens Mühle, Amber A. Leeson, Stephen A. Montzka, Wuhu Feng

Chemistry & Biochemistry Faculty Publications

Very short‐lived substances (VSLS), including dichloromethane (CH₂Cl₂), chloroform (CHCl₃), perchloroethylene (C₂Cl₄), and 1,2‐dichloroethane (C₂H₄Cl₂), are a stratospheric chlorine source and therefore contribute to ozone depletion. We quantify stratospheric chlorine trends from these VSLS (VSLCl_tot) using a chemical transport model and atmospheric measurements, including novel high‐altitude aircraft data from the NASA VIRGAS (2015) and POSIDON (2016) missions. We estimate VSLCl_tot increased from 69 (±14) parts per trillion (ppt) Cl in 2000 to 111 (±22) ppt Cl in 2017, with >80% delivered to …

Molecular Characterization Of Free Tropospheric Organic Aerosol And The Development Of Computational Tools For Molecular Formula Assignment, Simeon Schum

Dissertations, Master's Theses and Master's Reports

Organic aerosol affects human health and climate. These effects are largely determined by the composition of the organic aerosol, which is a complex mixture of species. Understanding the complexity of organic aerosol is critical to determining its effect on human health and climate. In this study, long range transported organic aerosol collected at the Pico Mountain Observatory was analyzed using ultrahigh resolution mass spectrometry. Organic aerosol transported in the free troposphere had an overall lower extent of oxidation than aerosol transported in the boundary layer. It was hypothesized that the lower oxidation was related to a more viscous phase state …

Aerosol-Cloud Interactions In Turbulent Clouds: A Combined Cloud Chamber And Theoretical Study, Kamal Kant Chandrakar

Dissertations, Master's Theses and Master's Reports

The influence of aerosol concentration on the cloud droplet size distribution is investigated in a laboratory chamber that enables turbulent cloud formation through moist convection. In chapter 2, moist Rayleigh-Bénard convection with water saturated boundaries is explored using a one-dimensional-turbulence model. This study provides some background about supersaturation statistics in moist convection. Chapters 3 - 7 discuss the experimental and theoretical investigation of aerosol-cloud interactions and cloud droplet size-distributions in turbulent conditions. The experiments are performed in a way so that steady-state microphysics are achieved, with aerosol input balanced by cloud droplet growth and fallout. As aerosol concentration is increased …

Light Propagation Through A Turbulent Cloud: Comparison Of Measured And Computed Extinction, Eduardo Rodriguez-Feo Bermudez

Dissertations, Master's Theses and Master's Reports

Remote sensing techniques used for measurement of atmospheric cloud properties operate under the notion that light extinction caused by scattering and absorption is exponential due to Beer-Lambert law. This is expected to be valid for a uni-form medium with no spatial correlations between particle position. The aim of this research was to show that under turbulent conditions, cloud droplets cannot be interpreted as non-correlated, and in turn will exhibit a lower than exponential light decay from scattering. The research took place at the MTU π-Chamber laboratory. A temperature difference between the floor and ceiling of the chamber was applied to …

A New Model For Lifting Condensation Levels Estimation, Nihad E. Daidzic Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

Knowledge of and the ability to predict lifting condensation levels (LCL) is important ingredient in weather predictions, cloud formation, planetary albedo and Earth’s energy balance. It is also essential topic in aviation safety and flight operations. In this article, we derive a new model of LCL and compare it to some older commonly-used models. This includes also the recently published Romps’ (2017) model. The new model presented here includes dependence, however weak, of the surface atmospheric pressure and the specific humidity on the LCL height and temperature. Such is not the case with widely used models and expressions by Espy …

Effect Of Carbonaceous Nanoparticles On Naturally Occurring Iron Reduction By Carboxylates, Ashleen Reddy

All Master's Theses

The emission of ambient particulate matter (PM) is regulated by many institutions due to the detrimental effects on health, environment and climate; yet many underlying mechanisms of PM reactivity are still not well understood. In the current study, the effect of carbonaceous nanoparticles (CNPs), contained within ultrafine PM (particle diameter ≤ 100 nm), is investigated on naturally occurring processes that increase the abundance of bioavailable iron. Enhancing iron bioavailability (i) increases primary productivity of iron-limited microorganisms, affecting the carbon cycle and global climate, and (ii) increase toxicity of inhaled particles through the associated production of reactive oxygen species (ROS). Specifically, …

Applications For Low Cost Sensors And Computing Platforms, Skylar Overby

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Modeled And Measured Ecosystem Respiration In Maize–Soybean Systems Over 10 Years, Ming Zhan, Adam Liska, Anthony Nguy-Robertson, Andrew E. Suyker, Matthew P. Pelton, Haishun Yang

Adam Liska Papers

Crop residue is an abundant resource for the potential production of biofuels, but a better understanding of its use on net carbon emissions must be developed to mitigate climate change. This analysis combines two established crop growth models (Hybrid-Maize and SoySim) with a simple soil and crop residue respiration model to estimate daily ecosystem respiration (ERe) from maize and soybean; ERe was estimated to be the sum of CO₂ emissions from the oxidation of the growing crop, crop residue, and soil organic carbon (SOC). Model-estimated CO₂ fluxes from irrigated continuous maize and irrigated maize–soybean cropping systems in eastern …

An Overview And Evaluation Of Synthetc: A Statistical Model For Extra-Tropical Cyclones, Rafael Uryayev

Dissertations and Theses

Extratropical cyclones (ETCs) are the most common weather phenomena affecting the United States, Canada, and Europe. They can pose serious hazards over large swaths of area. In this thesis, a statistical model of ETCs, called SynthETC, is discussed. The model accounts for the for genesis, track path, termination, and intensity of statistically generated ETCs. Genesis is modeled as a Poisson process, whose mean is determined by climate and historical information. Tracks are modeled as a regression-mean determined by climate and historical information plus a stochastic component. Lysis is modeled using logistic regression, with climate states as covariates. Intensity is modeled …

Classification Of Aerosol Population Type And Cloud Condensation Nuclei Properties In A Coastal California Littoral Environment Using An Unsupervised Cluster Model, Samuel A. Atwood, Sonia M. Kreidenweis, Paul J. Demott, Markus D. Petters, Gavin Cornwell, Andrew C. Martin, Kathryn A. Moore

Geography Faculty Publications and Presentations

Aerosol particle and cloud condensation nuclei (CCN) measurements from a littoral location on the northern coast of California at Bodega Bay Marine Laboratory (BML) are presented for approximately six weeks of observations during the boreal winter–spring as part of the CalWater-2015 field campaign. The nature and variability of surface (marine boundary layer, MBL) aerosol populations were evaluated by classifying observations into periods of similar aerosol and meteorological characteristics using an unsupervised cluster model to derive distinct littoral aerosol population types and link them to source regions. Such classifications support efforts to understand the impact of changing aerosol properties on precipitation …

A Recent Systematic Increase In Vapor Pressure Deficit Over Tropical South America, Armineh Barkhordarian, Bahareh Saatchi, Ali Behrangi, Paul C. Loikith, Carlos R. Mechoso

Geography Faculty Publications and Presentations

We show a recent increasing trend in Vapor Pressure Deficit (VPD) over tropical South America in dry months with values well beyond the range of trends due to natural variability of the climate system defined in both the undisturbed Preindustrial climate and the climate over 850–1850 perturbed with natural external forcing. This trend is systematic in the southeast Amazon but driven by episodic droughts (2005, 2010, 2015) in the northwest, with the highest recoded VPD since 1979 for the 2015 drought. The univariant detection analysis shows that the observed increase in VPD cannot be explained by greenhouse-gas-induced (GHG) radiative warming …

Investigation Of Light Transport And Scattering In Turbulent Clouds: Simulations And Laboratory Measurements, Corey D. Packard

Dissertations, Master's Theses and Master's Reports

A better understanding of light transport and scattering in turbulent clouds is needed for more accurate remote sensing, improved imaging and signal transmission through atmospheric aerosol and fog, and deeper understanding of cloud optical properties relevant to weather and climate. In this study, we investigate the impact of light scattering in clouds on two problems of atmospheric relevance.

In the first part, we examine deleterious effects of the atmosphere on remotely acquired images including signal attenuation and potential blurring due to forward-scattered light accepted by the imaging system. A prior proposed aerosol scattering model provides a method for calculating the …

A Climatological Study Of The Wet And Dry Conditions In The Presummer Monsoon Season Of The Philippines, Lyndon Mark Olaguera, Jun Matsumoto

Physics Faculty Publications

This study investigates the climatology of the wet and dry conditions in the pre‐summer monsoon season of the Philippines that are less emphasized in previous works. Wet cases (Type W), which account for about 23% of the total pre‐summer monsoon days from 1979 to 2015, are identified from April 1 to the monsoon onset defined by the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA). The differences between the Type W and dry cases (Type D) are presented. The synoptic conditions associated with the Type W and Type D cases are sub‐divided into two sub‐types based on the wind conditions, …

Size - Resolved Composition And Morphology Of Particulate Matter During The Southwest Monsoon In Metro Manila, Philippines, Melliza Templonuevo Cruz, Paola Angela Bañaga, Grace Betito, Rachel A. Braun, Connor Stahl, Mojtaba Azadi Aghdam, Maria Obiminda L. Cambaliza, Hossein Dadashazar, Miguel Ricardo Hilario, Genevieve Rose Lorenzo, Lin Ma, Alexander B. Macdonald, Preciosa Corazon Pabroa, John Robin Yee, James Bernard Simpas, Armin Sorooshian

Physics Faculty Publications

This paper presents novel results from size-resolved particulate matter (PM) mass, composition, and morphology measurements conducted during the 2018 southwest monsoon (SWM) season in Metro Manila, Philippines. Micro-orifice uniform deposit impactors (MOUDIs) were used to collect PM sample sets composed of size-resolved measurements at the following aerodynamic cut-point diameters (Dp): 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18, 0.10, and 0.056 µm. Each sample set was analyzed for composition of the water-soluble fraction. Analysis for mass was carried out on two sample sets, whereas black carbon (BC) and morphology analysis were analyzed on a single sample set. The bulk …