Automated Detection And Characterization Of Mesocyclones In X-Band Radar Observations,
2021
Purdue University
Automated Detection And Characterization Of Mesocyclones In X-Band Radar Observations, Raychel E. Nelson
The Journal of Purdue Undergraduate Research
No abstract provided.
The Effects Of Climate Change On The Vertical Structure Of Severe Weather Environments,
2021
Purdue University
The Effects Of Climate Change On The Vertical Structure Of Severe Weather Environments, Isaac Davis
The Journal of Purdue Undergraduate Research
No abstract provided.
Particulate Oxalate-To-Sulfate Ratio As An Aqueous Processing Marker: Similarity Across Field Campaigns And Limitations,
2021
University of Arizona
Particulate Oxalate-To-Sulfate Ratio As An Aqueous Processing Marker: Similarity Across Field Campaigns And Limitations, Miguel Ricardo A. Hilario, Ewan Crosbie, Paola Angela Bañaga, Grace Betito, Rachel A. Braun, Maria Obiminda L. Cambaliza, Andrea F. Corral, Melliza Templonuevo Cruz, Jackie E. Dibb, Genevieve Rose Lorenzo, Alexander B. Macdonald, Claire E. Robinson, Michael Shook, James Bernard Simpas, Connor Stahl, Edward Winstead, Luke Ziemba, Armin Sorooshian
Physics Faculty Publications
Leveraging aerosol data from multiple airborne and surface-based field campaigns encompassing diverse environmental conditions, we calculate statistics of the oxalate-sulfate mass ratio (median: 0.0217; 95% confidence interval: 0.0154 – 0.0296; R = 0.76; N = 2948). Ground-based measurements of the oxalate-sulfate ratio fall within our 95% confidence interval, suggesting the range is robust within the mixed layer for the submicrometer particle size range. We demonstrate that dust and biomass burning emissions can separately bias this ratio towards higher values by at least one order of magnitude. In the absence of these confounding factors, the 95% confidence interval of the ratio …
A Quasi-27-Day Oscillation Activity From The Troposphere To The Mesosphere And Lower Thermosphere At Low Latitudes,
2021
Wuhan University
A Quasi-27-Day Oscillation Activity From The Troposphere To The Mesosphere And Lower Thermosphere At Low Latitudes, Hao Cheng, Alan Z. Liu, Kaiming Huang, Shaodong Zhang, Chunming Huang, Yun Gong
Publications
Using meteor radar, radiosonde observations and MERRA-2 reanalysis data from 12 August to 31 October 2006, we report a dynamical coupling from the tropical lower atmosphere to the mesosphere and lower thermosphere through a quasi-27-day intraseasonal oscillation (ISO). It is interesting that the quasi-27-day ISO is observed in the troposphere, stratopause and mesopause regions, exhibiting a three-layer structure. In the MLT, the amplitude in the zonal wind increases from about 4 ms−1 at 90 km to 15 ms−1 at 100 km, which is diferent from previous observations that ISOs occurs generally in winter with an amplitude peak at about 80–90 …
Atmospheric Tomography Using The Nordic Meteor Radar Cluster And Chilean Observation Network De Meteor Radars: Network Details And 3d-Var Retrieval,
2021
University of Bern
Atmospheric Tomography Using The Nordic Meteor Radar Cluster And Chilean Observation Network De Meteor Radars: Network Details And 3d-Var Retrieval, Gunter Stober, Alan Z. Liu, Zishun Qiao, Alexander Kozlovsky, Masaki Tsutsumi, Chris Hall, Satonori Nozawa, Mark Lester, Evgenia Belova, Johan Kero, Patrick J. Espy, Robert E. Hibbins, Nicholas Mitchell
Publications
Ground-based remote sensing of atmospheric parameters is often limited to single station observations by vertical profiles at a certain geographic location. This is a limiting factor for investigating gravity wave dynamics as the spatial information is often missing, e.g., horizontal wavelength, propagation direction or intrinsic frequency. In this study, we present a new retrieval algorithm for multistatic meteor radar networks to obtain tomographic 3-D wind fields within a pre-defined domain area. The algorithm is part of the Agile Software for Gravity wAve Regional Dynamics (ASGARD) and called 3D-Var, and based on the optimal estimation technique and Bayesian statistics. The performance …
Greenhouse Gas Emissions And Drought Projections For Nebraska,
2021
University of Nebraska - Lincoln
Greenhouse Gas Emissions And Drought Projections For Nebraska, Adam Liska
Adam Liska Papers
This lecture will focus on three issues. The first is a presentation of data from the first greenhouse gas emissions inventory for the State of Nebraska, which will be published in the coming weeks. In 2016, emissions from beef cattle made up 23% of net state emissions, and coal for electricity made up 23.7% of net state emissions. The second issue to be addressed are the impacts of the 2012 drought on agriculture in Nebraska and the region. The drought of 2012 indicates that future droughts in the 21st century in the region can be a dominant influence on …
Understanding The Effects Of Wind Intensity, Forward Speed, Pressure And Track On Generation And Propagation Of Hurricane Irma Surges Around Florida,
2021
Tennessee State University
Understanding The Effects Of Wind Intensity, Forward Speed, Pressure And Track On Generation And Propagation Of Hurricane Irma Surges Around Florida, Abram Musinguzi, Madinah Shamsu, Muhammad K. Akbar, Jason G. Fleming
Mechanical and Manufacturing Engineering Faculty Research
In this study, it is demonstrated that hurricane wind intensity, forward speed, pressure, and track play an important role on the generation and propagation of coastal storm surges. Hurricane Irma, which heavily impacted the entire Florida peninsula in 2017, is used to study the storm surge sensitivity to varying storm characteristics. Results show that the west coast experiences a negative surge due to offshore wind of the approaching storm, but the positive surge returns after the hurricane eye passes over a location and wind became onshore. In the west coast peak, surges are intensified by an increase in onshore wind …
Profiling Atmospheric Turbulence Using A Dynamically Ranged Rayleigh Beacon System,
2021
Air Force Institute of Technology
Profiling Atmospheric Turbulence Using A Dynamically Ranged Rayleigh Beacon System, Steven M. Zuraski
Theses and Dissertations
The effect of turbulence on a long range imaging system manifest as an image blur effect usually quantified by the phase distortions present in a system. The blurring effect is conceivably understood on the basis of measured strength of atmospheric turbulence profiled within the propagation volume. One method for obtaining a turbulence strength profile is by use of a dynamically ranged Rayleigh beacon system that exploits strategically varied beacon ranges along the propagation path, effectively deducing estimates of specific path segment contributions of the blurring aberrations affecting an optical imaging system. A system utilizing this technique has been designed, and …
Subaperture Sampling For Digital-Holography Applications Involving Atmospheric Turbulence,
2021
Air Force Institute of Technology
Subaperture Sampling For Digital-Holography Applications Involving Atmospheric Turbulence, Douglas E. Thornton, Matthias T. Banet, Mark F. Spencer
Faculty Publications
Using wave-optics simulations, this paper defines what subaperture sampling effectively means for digital-holography applications involving atmospheric turbulence. Throughout, we consider the on-axis phase shifting recording geometry (PSRG) and off-axis PSRG, both with the effects of sensor noise. The results ultimately show that (1) insufficient subaperture sampling manifests as an efficiency loss that limits the achievable signal-to-noise ratio and field-estimated Strehl ratio; (2) digital-holography applications involving atmospheric turbulence require at least three focal-plane array (FPA) pixels per Fried coherence length to meet the Maréchal criterion; and (3) off-axis PSRG is a valid and efficient implementation with minor losses, as compared to …
Relationship Between Solar Energetic Particle He/H Abundance Ratios And Properties Of Flares And Cmes,
2021
Air Force Institute of Technology
Relationship Between Solar Energetic Particle He/H Abundance Ratios And Properties Of Flares And Cmes, Christopher R. Davidson
Theses and Dissertations
Previous studies have investigated the He/H elemental abundance ratios of Solar Energetic Particle (SEP) Events of energies above 4 MeV. Also, studies have investigated the correlations between SEPs, Coronal Mass Ejections (CME), and Solar Flares. This work finds the correlations between the >4 MeV He/H abundance ratios and the solar parameters from the SEP, CME, and solar flare associated with the abundance increases. 43 SEP events located at solar west longitude are analyzed to find the correlation coefficients. Highly significant correlation was found between the He/H abundance ratios and the following parameters: solar flare flux, solar flare fluence, CME linear …
Development And Verification Of Extreme Space Weather Phenomena Models,
2021
Air Force Institute of Technology
Development And Verification Of Extreme Space Weather Phenomena Models, Sophia G. Schwalbe
Theses and Dissertations
A range of 14 M-class flares from 1 June 2015 to 27 September 2016 were analyzed to find significant trends in electron frequency profile modeling using the GLobal airglOW (GLOW) model and radar parameters using a ray tracing algorithm developed by the Air Force Research Laboratory. GLOW was run for all the flares using three different solar spectrum schemes and an average of the three: the Hinteregger method, EUV flux model for aeronomic calculations (EUVAC), and a rebinned Flare Irradiance Spectrum Model (FISM) result. Comparing data for the E-layer where GLOW is most accurate, it was determined that GLOW using …
Unintended Consequences Of Air Cleaning Chemistry,
2021
Bucknell University
Unintended Consequences Of Air Cleaning Chemistry, Douglas B. Collins, Delphine K. Farmer
Faculty Journal Articles
Amplified interest in maintaining clean indoor air associated with the airborne transmission risks of SARS-CoV-2 have led to an expansion in the market for commercially available air cleaning systems. While the optimal way to mitigate indoor air pollutants or contaminants is to control (remove) the source, air cleaners are a tool for use when absolute source control is not possible. Interventions for indoor air quality management include physical removal of pollutants through ventilation or collection on filters and sorbent materials, along with chemically reactive processes that transform pollutants or seek to deactivate biological entities. This perspective intends to highlight the …
Venus Mountain Waves In The Upper Atmosphere Simulated By A Time-Invariant Linear Full-Wave Spectral Model,
2021
Embry-Riddle Aeronautical University
Venus Mountain Waves In The Upper Atmosphere Simulated By A Time-Invariant Linear Full-Wave Spectral Model, Michael P. Hickey, Thomas Navarro, Gerald Schubert, Richard L. Walterscheid
Publications
A 2-D spectral full-wave model is described that simulates the generation and propagation of mountain waves over idealized topography in Venus’ atmosphere. Modeled temperature perturbations are compared with the Akatsuki observations. Lower atmosphere eddy diffusivity and stability play a major role in the upward propagation of gravity waves from their mountain sources. Two local times (LT) are considered. For LT = 11h the waves are blocked by a critical level near 100 km altitude, while for LT = 16 h the waves propagate into the thermosphere. As a result of the small scale height in the Venus thermosphere, for LT …
Observations And Validation Of Plasma Density, Temperature, And O+ Abundance From A Langmuir Probe Onboard The International Space Station,
2021
Embry-Riddle Aeronautical University
Observations And Validation Of Plasma Density, Temperature, And O+ Abundance From A Langmuir Probe Onboard The International Space Station, Shantanab Debchoudhury, Aroh Barjatya, Joseph I. Minow, Victoria N. Coffey, Michael O. Chandler
Publications
The Floating Potential Measurement Unit (FPMU) has been operational on board the International Space Station (ISS) since 2006. One of the instruments in the FPMU suite is a spherical wide-sweeping Langmuir probe, referred to as the WLP, which is sampled at a temporal cadence of 1 s giving in-situ measurements of the plasma density and electron temperature. In this study we present our refinements to the Langmuir probe analysis algorithm that address the uncertainties associated with photoelectron emission current from the metal probe. We also derive the fraction of O+ ions as a secondary data product, which shows decrease …
High Altitude Ballooning As A Platform For Measuring Ozone Uptake Over Agricultural Landscapes,
2021
Depaul University
High Altitude Ballooning As A Platform For Measuring Ozone Uptake Over Agricultural Landscapes, Thomas Sykora, Mark Potosnak
DePaul Discoveries
Measuring plant health is a key aspect in maximizing crop outputs. One often overlooked risk to crop fields is damage caused by stomatal ozone uptake; measuring this uptake is an important tool in understanding crop losses. Traditional methods for measuring plant ozone uptake are prohibitively expensive and rely on equipment that cannot easily be moved. Here, we propose high-altitude weather ballooning as a cost-effective alternative for measuring ozone uptake on a regional (~10 km) spatial scale. Ozonesounde data was obtained with weather balloons launched from the National Oceanic and Atmospheric Administration research station in Boulder, Colorado. This data was then …
An Investigation Into The Thermodynamics Of Overland Tropical Cyclone Intensity Change In Weakly/Non-Baroclinic Environments,
2021
University of Wisconsin-Milwaukee
An Investigation Into The Thermodynamics Of Overland Tropical Cyclone Intensity Change In Weakly/Non-Baroclinic Environments, Michael Partrick Vossen
Theses and Dissertations
There are two leading theories regarding how tropical cyclones can maintain or increase their intensity over land in weakly to non-baroclinic environments. In the first, tropical cyclones are maintained overland by enhanced upward surface enthalpy fluxes facilitated by the tropical cyclone’s rains, whereas in the second, tropical cyclones are maintained by enhanced enthalpy fluxes under inflowing trajectories at larger radii from the cyclone’s center. These theories have yet to be rigorously tested, however. To rigorously test these hypotheses, this study uses a quasi-idealized version of the Weather Research and Forecasting model lacking parameterized radiation to test the sensitivity of overland …
Verification Of Environmental-Regime–Stratified Gfs Short-Range Vertical Sounding Forecasts,
2021
University of Wisconsin-Milwaukee
Verification Of Environmental-Regime–Stratified Gfs Short-Range Vertical Sounding Forecasts, Dillon Blount
Theses and Dissertations
In recent years, the United States’ operational global numerical weather prediction model, the Global Forecast System (GFS), has been upgraded to include a new dynamical core and an updated turbulence parameterization. This updated turbulence parameterization uses a hybrid eddy-diffusivity, countergradient, and mass-flux formulation to approximate near-surface turbulent vertical mixing. The precise formulation used is based on the local stability, with the eddy-diffusivity, countergradient, and mass flux formulations used under stable, weakly unstable, and strongly unstable conditions, respectively. In this study, an objective classification of environmental regimes is used to verify GFS short-range vertical soundings, focusing on the planetary boundary layer …
Studies Of The Planetary Boundary Layer And Their Impact On Air Pollution In A Semi-Arid Region With Complex Terrain,
2021
University of Texas at El Paso
Studies Of The Planetary Boundary Layer And Their Impact On Air Pollution In A Semi-Arid Region With Complex Terrain, Nakul Nitin Karle
Open Access Theses & Dissertations
The adjacent cities of El Paso-Juárez, located in the Rio Grande Rift Valley and surrounded by complex mountainous terrain, have undergone rapid urbanization and industrial growth in the last few decades, accompanied by increasing substandard air quality episodes. Although numerous air quality studies were conducted in this semi-arid region in the past, none focused extensively on the Planetary Boundary Layer (PBL) contribution and impact on air pollutant concentrations. In this work, both the high and low ozone episodes from 2015 to 2020 were examined. Both modeling and experimental data of the PBL height (PBLH) were obtained and related to atmospheric …
Regional Characteristics And Variability Of Extreme Precipitation And Atmospheric Rivers In Past, Present, And Future Climates Over The Contiguous United States,
2021
Portland State University
Regional Characteristics And Variability Of Extreme Precipitation And Atmospheric Rivers In Past, Present, And Future Climates Over The Contiguous United States, Emily Anne Slinskey
Dissertations and Theses
This dissertation examines the regional and seasonal variability of extreme precipitation and atmospheric rivers (ARs) across the contiguous United States (CONUS) in past, present, and future climates. An extreme precipitation categorization scheme, designed to monitor and track the multi-scale variability of extreme precipitation, is applied to a range of precipitation measurement products as an assessment of observational uncertainty. To investigate the importance of ARs across the CONUS, an objective AR identification algorithm is applied to global reanalysis to identify and characterize AR characteristics regionally over the observational record. Projected change in AR day frequency, geometry, intensity, and associated precipitation is …
Climate Model Evaluation Of Atmospheric Rivers Over The Contiguous United States,
2021
Portland State University
Climate Model Evaluation Of Atmospheric Rivers Over The Contiguous United States, Ilan González-Hirshfeld
Dissertations and Theses
Atmospheric rivers (ARs)--long corridors of intense atmospheric water vapor transport--significantly influence the hydrologic cycle and regional hydrometeorological extremes across the contiguous United States (CONUS). Ongoing and future climate change may alter AR characteristics and impacts, making confident climate model projections of future change, especially at regional scales, of critical importance. In order to better constrain uncertainty in such projections of future change, we perform a comprehensive climate model evaluation of AR climatology over the CONUS. Using an established AR detection algorithm, we evaluate the representation of ARs in historical simulations (1984-2013) from a suite of models participating in the sixth …
