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Articles 91 - 120 of 1382

Full-Text Articles in Physical Sciences and Mathematics

Dynamics Of A 3-D Inlet/Isolator Measured With Fast Pressure-Sensitive Paint, Andrew N. Bustard, Mark E. Noftz, Mitsugu Hasegawa, Hirotaka Sakaue, Joseph S. Jewell, Nicholas J. Bisek, Thomas J. Juliano Jan 2024

Dynamics Of A 3-D Inlet/Isolator Measured With Fast Pressure-Sensitive Paint, Andrew N. Bustard, Mark E. Noftz, Mitsugu Hasegawa, Hirotaka Sakaue, Joseph S. Jewell, Nicholas J. Bisek, Thomas J. Juliano

Publications

Fast pressure-sensitive paint (PSP) was applied to an inlet/isolator designed using the Osculating Internal Waverider Inlet with Parallel Streamlines (OIWPS) method. The dorsal isolator surface pressure was measured using anodized-aluminum PSP through transparent cast acrylic that makes up the ventral portion of the isolator. Temperature-sensitive paint was utilized to correct for the PSP’s temperature sensitivity. The model was tested under Mach 5.7 flow at Re = 8.5 ×106 /m and 10.2 ×106 /m in the AFOSR–Notre Dame Large Mach-6 Quiet Tunnel (ANDLM6QT) under conventional noise conditions. Flow phenomena, such as shocks originating in the inlet and flow separation at the …


The High Energy X-Ray Probe (Hex-P): A New Window Into Neutron Star Accretion, R.M. Ludlam, C. Malacaria, E. Sokolova-Lapa, F. Fuerst, P. Pradhan, A.W. Shaw, K. Pottschmidt, S. Pike, G. Vasilopoulos, J. Wilms, J.A. Garcia, K. Madsen, D. Stern, C. Maitra, M. Del Santo, D.J. Walton, M.C. Brumback, J. Van Den Eijnden Dec 2023

The High Energy X-Ray Probe (Hex-P): A New Window Into Neutron Star Accretion, R.M. Ludlam, C. Malacaria, E. Sokolova-Lapa, F. Fuerst, P. Pradhan, A.W. Shaw, K. Pottschmidt, S. Pike, G. Vasilopoulos, J. Wilms, J.A. Garcia, K. Madsen, D. Stern, C. Maitra, M. Del Santo, D.J. Walton, M.C. Brumback, J. Van Den Eijnden

Publications

Accreting neutron stars (NSs) represent a unique laboratory for probing the physics of accretion in the presence of strong magnetic fields (B ≳ 108 G). Additionally, the matter inside the NS itself exists in an ultra-dense, cold state that cannot be reproduced in Earth-based laboratories. Hence, observational studies of these objects are a way to probe the most extreme physical regimes. Here we present an overview of the field and discuss the most important outstanding problems related to NS accretion. We show how these open questions regarding accreting NSs in both low-mass and high-mass X-ray binary systems can …


Exploring The Nexus Of Cybersecurity Leadership, Human Factors, Emotional Intelligence, Innovative Work Behavior, And Critical Leadership Traits, Sharon L. Burton, Darrell Norman Burrell, Calvin Nobles, Laura A. Jones Dec 2023

Exploring The Nexus Of Cybersecurity Leadership, Human Factors, Emotional Intelligence, Innovative Work Behavior, And Critical Leadership Traits, Sharon L. Burton, Darrell Norman Burrell, Calvin Nobles, Laura A. Jones

Publications

Data shows that 12% of leaders are rated as 'very effective' at leadership. This research emphasizes the importance of understanding human behavior and its impact on leadership effectiveness, innovative work behavior (IWB), and the ability to respond to complex cyber threats, particularly in the realm of cybersecurity leadership. Emotional intelligence (EI), a key human factor, is highlighted as a crucial element that can stimulate cognitive absorption, leading to innovative work behavior and improved innovation efficiency (IE). This underscores the need for leaders to not only be technically proficient but also emotionally intelligent to effectively manage their teams and respond to …


Impact Of Weather Factors On Airport Arrival Rates: Application Of Machine Learning In Air Transportation, Robert W. Maxson, Dothang Truong, Woojin Choi Dec 2023

Impact Of Weather Factors On Airport Arrival Rates: Application Of Machine Learning In Air Transportation, Robert W. Maxson, Dothang Truong, Woojin Choi

Publications

Weather is responsible for approximately 70% of air transportation delays in the National Airspace System, and delays resulting from convective weather alone cost airlines and passengers millions of dollars each year due to delays that could be avoided. This research sought to establish relationships between environmental variables and airport efficiency estimates by data mining archived weather and airport performance data at ten geographically and climatologically different airports. Several meaningful relationships were discovered from six out of ten airports using various machine learning methods within an overarching data mining protocol, and the developed models were tested using historical data.


Multi-Layer Evolution Of Acoustic-Gravity Waves And Ionospheric Disturbances Over The United States After The 2022 Hunga Tonga Volcano Eruption, P. A. Inchin, A. Bhatt, S. A. Cummer, S. D. Eckermann, B. J. Harding, J. Ma, J. J. Makela, J B. Snively Dec 2023

Multi-Layer Evolution Of Acoustic-Gravity Waves And Ionospheric Disturbances Over The United States After The 2022 Hunga Tonga Volcano Eruption, P. A. Inchin, A. Bhatt, S. A. Cummer, S. D. Eckermann, B. J. Harding, J. Ma, J. J. Makela, J B. Snively

Publications

e Hunga-Tonga Hunga-Ha'apai volcano underwent a series of large-magnitude eruptions that generated in the atmosphere. We investigate the spatial and temporal evolutions of fluctuations driven by atmospheric acoustic-gravity waves (AGWs) and, in particular, the Lamb wave modes in high spatial resolution data sets measured over the Continental United States (CONUS), complemented with data over the Americas and the Pacific. Along with >800 barometer sites, tropospheric observations, and Total Electron Content data from >3,000 receivers, we report detections of volcano-induced AGWs in mesopause and ionosphere-thermosphere airglow imagery and Fabry-Perot interferometry. We also report unique AGW signatures in the ionospheric D-region, measured …


The Life Cycle Of Stars And Their Planets From The High Energy Perspective, Lia Corrales, Keivan G. Stassun, Tim Cunningham, Girish M. Duvvuri, Jeremy J. Drake, Catherine Espaillat, Adina D. Feinstein, Elena Gallo, Hans Moritz Günther, George W. King, Marina Kounkel, Carey M. Lisse, Rodolfo Montez Jr., David A. Principe, Jesús A. Toalá, Scott J. Wolk, Raven Cilley, Tansu Daylan, Margarita Karovska, Pragati Pradhan, Peter J. Wheatley, Jun Yang Nov 2023

The Life Cycle Of Stars And Their Planets From The High Energy Perspective, Lia Corrales, Keivan G. Stassun, Tim Cunningham, Girish M. Duvvuri, Jeremy J. Drake, Catherine Espaillat, Adina D. Feinstein, Elena Gallo, Hans Moritz Günther, George W. King, Marina Kounkel, Carey M. Lisse, Rodolfo Montez Jr., David A. Principe, Jesús A. Toalá, Scott J. Wolk, Raven Cilley, Tansu Daylan, Margarita Karovska, Pragati Pradhan, Peter J. Wheatley, Jun Yang

Publications

One of the key research themes identified by the Astro2020 decadal survey is Worlds and Suns in Context. The Advanced X-ray Imaging Satellite (AXIS) is a proposed NASA APEX mission that will become the prime high-energy instrument for studying star-planet connections from birth to death. This work explores the major advances in this broad domain of research that will be enabled by the AXIS mission, through X-ray observations of stars in clusters spanning a broad range of ages, flaring M-dwarf stars known to host exoplanets, and young stars exhibiting accretion interactions with their protoplanetary disks. In addition, we explore the …


Flying To Net Zero With Sustainable Atos; Changing Cultures​, Eva Maleviti Nov 2023

Flying To Net Zero With Sustainable Atos; Changing Cultures​, Eva Maleviti

Publications

What is Sustainability?

  • World Commission on Environment and Development’s (WCED) 1987 Brundtland Report ‘’Our Common Future’’.
  • Help world nations towards sustainable development.

17 Sustainable Development Goals

  • The start of all industries are the 17 SDGs
  • Aviation can address the 15 SDGs
  • Net zero target suggest reduction of aviation emissions up to 21.2 Gt CO2


Gravity Waves Generated By The Hunga Tonga-Hunga Ha‘Apai Volcanic Eruption And Their Global Propagation In The Mesosphere/Lower Thermosphere Observed By Meteor Radars And Modeled With The High-Altitude General Mechanistic Circulation Model, Gunter Stober, Sharon L. Vadas, Erich Becker, Alan Liu, Diego Janches, Zishun Qiao, Et.Al Oct 2023

Gravity Waves Generated By The Hunga Tonga-Hunga Ha‘Apai Volcanic Eruption And Their Global Propagation In The Mesosphere/Lower Thermosphere Observed By Meteor Radars And Modeled With The High-Altitude General Mechanistic Circulation Model, Gunter Stober, Sharon L. Vadas, Erich Becker, Alan Liu, Diego Janches, Zishun Qiao, Et.Al

Publications

The Hunga Tonga-Hunga Ha‘apai volcano erupted on 15th January 2022, launching Lamb waves and gravity waves into the atmosphere. In this study, we present results using 13 globally distributed meteor radars and identify the volcanic- caused gravity waves in the mesospheric/lower thermospheric winds. Leveraging the High-Altitude Mechanistic General Circulation Model (HIAMCM), we compare the global propagation of these gravity waves. We observed an eastward propagating gravity wave packet with an observed phase speed of 240±5.7 m/s and a westward propagating gravity wave with an observed phase speed of 166.5 ±6.4 m/s. We identified these waves in the HIAMCM and obtained …


The Gbt Diffuse Ionized Gas Survey (Gdigs): Discrete Sources, Dylan J. Linville, Matteo Luisi, Bin Liu, T. M. Bania, Dana S. Balser, Trey V. Wenger, L. M. Haffner Oct 2023

The Gbt Diffuse Ionized Gas Survey (Gdigs): Discrete Sources, Dylan J. Linville, Matteo Luisi, Bin Liu, T. M. Bania, Dana S. Balser, Trey V. Wenger, L. M. Haffner

Publications

The Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by observing radio recombination line (RRL) emission from 4–8 GHz. The nominal survey zone is 32.3◦ > ℓ > −5◦, | b | < 0.5◦. Here, we analyze GDIGS Hnα ionized gas emission toward discrete sources. Using GDIGS data, we identify the velocity of 35 H II regions that have multiple detected RRL velocity components. We identify and characterize RRL emission from 88 H II regions that previously lacked measured ionized gas velocities. We also identify and characterize RRL emission from eight locations that appear to be previously-unidentified H II regions and 30 locations of RRL emission that do not appear to be H II regions based on their lack of mid-infrared emission. This latter group may be a compact component of the Galactic Diffuse Ionized Gas (DIG). There are an additional 10 discrete sources that have anomalously high RRL velocities for their locations in the Galactic plane. We compare these objects’ RRL data to 13CO, H I and mid-infrared data, and find that these sources do not have the expected 24 µm emission characteristic of H II regions. Based on this comparison we do not think these objects are H II regions, but we are unable to classify them as a known type of object.


Beyond 365 Days: A Retrospective Evaluation Of Trekkers, Sarah Krichels Goan Mpp, Madison Burke Oct 2023

Beyond 365 Days: A Retrospective Evaluation Of Trekkers, Sarah Krichels Goan Mpp, Madison Burke

Publications

The Trekkers program in Rockland, ME is a non-profit outdoor-based mentoring program that has served young people in mid-coast Maine since 1994. Its unique long-term mentoring model supports students over six years that begins when they are in 7th grade and continues until they graduate high school. Trekkers’ model focuses on building social, emotional and intellectual resiliency in young people through one-to-one peer mentoring, as well as the use of expeditionary learning, community service and adventure-based education. Trekkers’ programs are designed to provide an ongoing supportive network for young people in the community by connecting them with caring adults while …


On The Propagation Of Whistler-Mode Waves In The 2 Magnetic Ducts, Salman A. Nejad, Anatoly V. Streltsov Sep 2023

On The Propagation Of Whistler-Mode Waves In The 2 Magnetic Ducts, Salman A. Nejad, Anatoly V. Streltsov

Publications

This paper studies extremely-low frequency (ELF) whistler-mode waves’ behavior within small-scale magnetic field irregularities in the Earth’s magnetosphere, known as magnetic ducts. Based on the magnetic fields’ magnitude inside and outside these ducts, they are categorized as high-magnetic ducts (HBD) and low-magnetic ducts (LBD). Using the whistler-mode dispersion relation analysis, our primary focus is to show that LBDs are prone to leak electromagnetic energy outside the duct. We further investigate the hypothesis that whistlers can propagate within LBDs without any signal loss when the width of the duct corresponds to an integer multiple of the perpendicular wavelengths of the waves …


A "Boreing" Night Of Observations Of The Upper Mesosphere And Lower Thermosphere Over The Andes Lidar Observatory, J. H. Hecht, Alan Liu, D. C. Fritts, R. L. Walterscheid, L. J. Gelinas, R. J. Rudy Sep 2023

A "Boreing" Night Of Observations Of The Upper Mesosphere And Lower Thermosphere Over The Andes Lidar Observatory, J. H. Hecht, Alan Liu, D. C. Fritts, R. L. Walterscheid, L. J. Gelinas, R. J. Rudy

Publications

A very high-spatial resolution (∼21-23 m pixel at 85 km altitude) OH airglow imager at the Andes Lidar Observatory at Cerro Pach´on, Chile observed considerable ducted wave activity on the night of October 29-30, 2016. This instrument was collocated with a Na wind-temperature lidar that provided data revealing the occurrence of strong ducts. A large field of view OH and greenline airglow imager showed waves present over a vertical extent consistent with the altitudes of the ducting features identified in the lidar profiles. While waves that appeared to be ducted were seen in all imagers throughout the observation interval, the …


The Rs Oph Outburst Of 2021 Monitored In X-Rays With Nicer, Marina Orio, Keith Gendreau, Morgan Giese, Gerardo Jaun M. Luna, Jozef Magdolen, Tod E. Strohmayer, Andy E. Zhang, Diego Altamirano, Andrej Dobrotka, Teruaki Enoto, Elizabeth C. Ferrara, Richard Ignace, Sebastian Heinz, Craig Markwardt, Joy S. Nichols, Michael L. Parker, Dheeraj R. Pasham, Songpeng Pei, Pragati Pradhan, Ron Remillard, James F. Steiner, Francesco Tombesi Sep 2023

The Rs Oph Outburst Of 2021 Monitored In X-Rays With Nicer, Marina Orio, Keith Gendreau, Morgan Giese, Gerardo Jaun M. Luna, Jozef Magdolen, Tod E. Strohmayer, Andy E. Zhang, Diego Altamirano, Andrej Dobrotka, Teruaki Enoto, Elizabeth C. Ferrara, Richard Ignace, Sebastian Heinz, Craig Markwardt, Joy S. Nichols, Michael L. Parker, Dheeraj R. Pasham, Songpeng Pei, Pragati Pradhan, Ron Remillard, James F. Steiner, Francesco Tombesi

Publications

The 2021 outburst of the symbiotic recurrent nova RS Oph was monitored with the Neutron Star Interior Composition Explorer Mission (NICER) in the 0.2–12 keV range from day one after the optical maximum, until day 88, producing an unprecedented, detailed view of the outburst development. The X-ray flux preceding the supersoft X-ray phase peaked almost 5 days after optical maximum and originated only in shocked ejecta for 21–25 days. The emission was thermal; in the first 5 days, only a non-collisional-ionization equilibrium model fits the spectrum, and a transition to equilibrium occurred between days 6 and 12. The ratio of …


Survey Of X-Rays From Massive Stars Observed At High Spectral Resolution With Chandra, Pragati Pradhan, David P. Huenemoerder, Richard Ignace, Joy S. Nichols, A.M.T. Pollock Sep 2023

Survey Of X-Rays From Massive Stars Observed At High Spectral Resolution With Chandra, Pragati Pradhan, David P. Huenemoerder, Richard Ignace, Joy S. Nichols, A.M.T. Pollock

Publications

Identifying trends between observational data and the range of physical parameters of massive stars is a critical step to the still-elusive full understanding of the source, structure, and evolution of X-ray emission from the stellar winds, requiring a substantial sample size and systematic analysis methods. As of 2022, the Chandra data archive contains 37 high-resolution spectra of O, B, and WR stars, observed with the Chandra/HETGS, and of sufficient quality to fit the continua and emission-line profiles. Using a systematic approach to the data analysis, we explore morphological trends in the line profiles (i.e., O, Ne, Mg, and Si) and …


Osher Map Library And Smith Center For Cartographic Education: A Five-Year Retrospective Impact Report, Elora Way, Emma Schwartz, Madison Burke, Becky Wurwarg Sep 2023

Osher Map Library And Smith Center For Cartographic Education: A Five-Year Retrospective Impact Report, Elora Way, Emma Schwartz, Madison Burke, Becky Wurwarg

Publications

Since 1994, the Osher Map Library and Smith Center for Cartographic Education (OML) has been located within the Glickman Family Library on the Portland campus of the University of Southern Maine (USM). From its inception, the OML has been charged with not only expanding and preserving its collections, but with operating in the spirit of lifelong learning and a deep commitment to engaging scholars, students (Kindergarten through higher education), educators, community partners, and the public. OML meets this charge through various strategies and activities that include: educational outreach with Kindergarten (K) through 12th grade students and university students; professional development …


Quiet, But Not Silent: Uncovering Quiescent State Properties Of Two Transient High-Mass X-Ray Binaries, Gayathri Raman, Pragati Pradhan, Jamie Kennea Sep 2023

Quiet, But Not Silent: Uncovering Quiescent State Properties Of Two Transient High-Mass X-Ray Binaries, Gayathri Raman, Pragati Pradhan, Jamie Kennea

Publications

We present the first set of broad-band spectral and timing studies of two transient X-ray pulsars, MXB 0656 −072 and MAXI J1409 −619 using NuSTAR observations conducted during quiescence. Despite being captured at one of their lowest luminosity states, both these targets show signs of ongoing low-level accretion. Results from the time-averaged spectral analysis indicate for the first time, the presence of a strong soft power-law component along with thermal emission from the neutron star hotspots. For both targets, the quiescent thermal X-ray emission is consistent with the deep crustal heating model. In MXB 0656 −072, we do not detect …


The Varied Landscape Of Consumer Fraud, Alan Saquella Aug 2023

The Varied Landscape Of Consumer Fraud, Alan Saquella

Publications

In today's interconnected world, consumer fraud remains a persistent threat that can have far-reaching consequences for individuals and their financial well-being. While these insights are relatively current, it's essential to acknowledge that specific numbers and trends may have.


Probing The Foreshock Wave Boundary With Single Spacecraft Techniques, S. Dorfman, Kun Zhang, L. Ture, U. Ganse, M. Palmroth Aug 2023

Probing The Foreshock Wave Boundary With Single Spacecraft Techniques, S. Dorfman, Kun Zhang, L. Ture, U. Ganse, M. Palmroth

Publications

In space physics, wave measurements typically use a small number of datapoints due to limited available spacecraft. Common single-spacecraft wave vector analysis techniques built around these limitations are widely used, even in regions where the wave amplitude profile may have a strong spatial dependence. We show that in these gradient regions, the divergence-free condition of the magnetic field requires a local modification to the plane of polarization that is incorrectly interpreted by single-spacecraft techniques. We explore the consequences of this result in the Earth's ion foreshock using both Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun …


Whistler-Mode Waves In Magnetic Ducts, Anatoly V. Streltsov, Salman A. Nejad Aug 2023

Whistler-Mode Waves In Magnetic Ducts, Anatoly V. Streltsov, Salman A. Nejad

Publications

Observations from the NASA MMS satellites show packages of ELF whistler-mode waves localized inside the small-scale irregularities of the magnetic field. These irregularities are formed by the narrow field-aligned channels where the magnitude of the background magnetic field inside the channel is greater or less than outside. By analogy with the classical density ducts, we introduce the high-B duct (HBD), where the magnitude of the field inside the channel is greater than the outside, and the low-B duct (LBD), where the magnitude of the field inside the channel is less than the outside. We investigate the guiding of the ELF …


Advancing Our Understanding Of Martian Proton Aurora Through A Coordinated Multi-Model Comparison Campaign, Andrea C. G. Hughes, Michael Scott Chaffin, Edwin J. Mierkiewicz, Justin Deighan, Rebecca Jolitz, Esa Kallio, Guillaume Gronof, Valery I. Shematovich, Dmitry Bisikalo, Cyril L. Simon Wedlund, Jasper S. Halekas, Nicholas M. Schneider, Birgit Ritter, Zachary Girazian, Sonal Jain, Jean-Claude M. C. G´Erard, Bradley Michael Hegyi Jul 2023

Advancing Our Understanding Of Martian Proton Aurora Through A Coordinated Multi-Model Comparison Campaign, Andrea C. G. Hughes, Michael Scott Chaffin, Edwin J. Mierkiewicz, Justin Deighan, Rebecca Jolitz, Esa Kallio, Guillaume Gronof, Valery I. Shematovich, Dmitry Bisikalo, Cyril L. Simon Wedlund, Jasper S. Halekas, Nicholas M. Schneider, Birgit Ritter, Zachary Girazian, Sonal Jain, Jean-Claude M. C. G´Erard, Bradley Michael Hegyi

Publications

Proton aurora are the most commonly observed yet least studied type of aurora at Mars. In order to better understand the physics and driving processes of Martian proton aurora, we undertake a multi-model comparison campaign. We compare results from four different proton/hydrogen precipitation models with unique abilities to represent Martian proton aurora: Jolitz model (3-D Monte Carlo), Kallio model (3-D Monte Carlo), Bisikalo/Shematovich et al. model (1-D kinetic Monte Carlo), and Gronoff et al. model (1-D kinetic). This campaign is divided into two steps: an inter-model comparison and a data-model comparison. The inter-model comparison entails modeling five different representative cases …


Probabilistic Modeling Of North Atlantic Ocean Hurricane Spawn Considering Climate Change, Susmita Bhowmik, Weichiang Pang, Michael Stoner Jul 2023

Probabilistic Modeling Of North Atlantic Ocean Hurricane Spawn Considering Climate Change, Susmita Bhowmik, Weichiang Pang, Michael Stoner

Publications

Hurricanes are a significant natural hazard, which cause significant damage and financial losses in the coastal areas of the United States almost every year. For example, the devastating nature of North Atlantic Ocean (NAO) storms can easily be understood from the 2005 Hurricane Katrina, which was the most damaging NAO storm in modern history, causing more than 1,800 deaths and a financial loss of at least 161.3 billion USD. It has been found that the formations of hurricanes depend heavily on climate conditions, which implies a direct relationship between the changes in climate extremes and the occurrences of hurricanes or …


Estimation Of The Kelvin–Helmholtz Unstable Boundary, Xuanye Ma Jul 2023

Estimation Of The Kelvin–Helmholtz Unstable Boundary, Xuanye Ma

Publications

The Kelvin–Helmholtz (KH) instability is one of the most important mechanisms of the viscous like interaction between the solar wind and the magnetosphere (MSP), which transport the mass, energy, momentum, and magnetic flux. Thus, it is important to examine whether the magnetopause boundary is KH unstable or not. Based on the KH onset conditions, this report proposes to use a matrix to identify the most KH unstable direction based on the in-situ measurements of the density, velocity, and magnetic field in the MSP and magneto sheath. The range of the KH unstable direction can be easily estimated based on the …


Hyper-Local Weather Predictions With The Enhanced General Urban Area Microclimate Predictions Tool, Kevin A. Adkins, William Becker, Sricharan Ayyalasomayajula, Steven Lavenstein, Kleoniki Vlachou, David Miller, Marc Compere, Avinash Muthu Krishnan, Nickolas Macchiarella Jun 2023

Hyper-Local Weather Predictions With The Enhanced General Urban Area Microclimate Predictions Tool, Kevin A. Adkins, William Becker, Sricharan Ayyalasomayajula, Steven Lavenstein, Kleoniki Vlachou, David Miller, Marc Compere, Avinash Muthu Krishnan, Nickolas Macchiarella

Publications

This paper presents enhancements to, and the demonstration of, the General Urban area Microclimate Predictions tool (GUMP), which is designed to provide hyper-local weather predictions by combining machine-learning (ML) models and computational fluid dynamic (CFD) simulations. For the further development and demonstration of GUMP, the Embry–Riddle Aeronautical University (ERAU) campus was used as a test environment. Local weather sensors provided data to train ML models, and CFD models of urban- and suburban-like areas of ERAU’s campus were created and iterated through with a wide assortment of inlet wind speed and direction combinations. ML weather sensor predictions were combined with best-fit …


Extreme Horizontal Wind Perturbations In The Mesosphere And Lower Thermosphere Over South America Associated With The 2022 Hunga Eruption, Facundo L. Poblet, Jorge L. Chau, J. Federico Conte, Juha Vierinen, Jose Suclupe, Alan Liu, Rodolfo R. Rodriguez Jun 2023

Extreme Horizontal Wind Perturbations In The Mesosphere And Lower Thermosphere Over South America Associated With The 2022 Hunga Eruption, Facundo L. Poblet, Jorge L. Chau, J. Federico Conte, Juha Vierinen, Jose Suclupe, Alan Liu, Rodolfo R. Rodriguez

Publications

On 15 January 2022, the Hunga volcano produced a massive explosion that generated perturbations in the entire atmosphere. Nonetheless, signatures in the mesosphere and lower thermosphere (MLT) have been challenging to identify. We report MLT horizontal wind perturbations using three multistatic specular meteor radars on the west side of South America (spanning more than 3,000 km). The most notorious signal is an exceptional solitary wave with a large vertical wavelength observed around 18 UT at all three sites, with an amplitude of ∼50 m/s mainly in the westward direction. Using a customized analysis, the wave is characterized as traveling at …


Bayesian Inference For The White Dwarf Initial-Final Mass Relation, Nathan Stein, Ted Von Hippel, David Van Dyk, Steven Degennaro, Elizabeth Jeffery, Bill Jefferys Jun 2023

Bayesian Inference For The White Dwarf Initial-Final Mass Relation, Nathan Stein, Ted Von Hippel, David Van Dyk, Steven Degennaro, Elizabeth Jeffery, Bill Jefferys

Publications

Stars lose mass as they age, and understanding mass loss is important for understanding stellar evolution. The initial-final mass relation (IFMR) is the relationship between a white dwarf’s initial mass on the main sequence and its final mass. We have developed a new method for fitting the IFMR based on a Bayesian analysis of photometric observations, combining deterministic models of stellar evolution in an internally coherent way. No mass data are used. Our method yields precise inferences (with uncertainties) for a parameterized linear IFMR. Our method can also return posterior distributions of white dwarf initial and final masses.


Databases And Inter-Connectivity In Ground-Based Astronomy, Ted Von Hippel, C. M. Mountain Jun 2023

Databases And Inter-Connectivity In Ground-Based Astronomy, Ted Von Hippel, C. M. Mountain

Publications

Optical and infrared ground-based astronomy is undergoing a renaissance. Advances in material technology, system modeling, and the ability to correct atmospheric distortions in real time have produced a new generation of powerful, large telescopes. An equally profound revolution stems from the availability of large observational databases that span the electromagnetic spectrum. The increased use of such databases as well as the need to operate the new telescopes efficiently requires the development of a National or International Virtual Observatory to set standards for astronomical database formats, data quality assurance, and access protocols, and also to provide all-inclusive centers for data products.


The Effect Of Advection On The Three Dimensional Distribution Of Turbulent Kinetic Energy And Its Generation In Idealized Tropical Cyclone Simulations, Joshua B. Wadler, David S. Nolan, Jun A. Zhang, Lynn K. Shay, Joseph B. Olsen, Joseph J. Cione May 2023

The Effect Of Advection On The Three Dimensional Distribution Of Turbulent Kinetic Energy And Its Generation In Idealized Tropical Cyclone Simulations, Joshua B. Wadler, David S. Nolan, Jun A. Zhang, Lynn K. Shay, Joseph B. Olsen, Joseph J. Cione

Publications

The distribution of turbulent kinetic energy (TKE) and its budget terms is estimated in simulated tropical cyclones (TCs) of various intensities. Each simulated TC is subject to storm motion, wind shear, and oceanic coupling. Different storm intensities are achieved through different ocean profiles in the model initialization. For each oceanic profile, the atmospheric simulations are performed with and without TKE advection. In all simulations, the TKE is maximized at low levels (i.e., below 1 km) and ∼0.5 km radially inward of the azimuthal-mean radius of maximum wind speed at 1-km height. As in a previous study, the axisymmetric TKE decreases …


Identifying Gravity Waves Launched By The Hunga Tonga–Hunga Ha’Apai Volcanic Eruption In Mesosphere/Lower-Thermosphere Winds Derived From Condor And The Nordic Meteor Radar Cluster, Gunter Stober, Alan Liu, Alexander Kozlovsky, Zishun Qiao, Witali Krochin, Guochun Shi, Johan Kero, Et Al. Apr 2023

Identifying Gravity Waves Launched By The Hunga Tonga–Hunga Ha’Apai Volcanic Eruption In Mesosphere/Lower-Thermosphere Winds Derived From Condor And The Nordic Meteor Radar Cluster, Gunter Stober, Alan Liu, Alexander Kozlovsky, Zishun Qiao, Witali Krochin, Guochun Shi, Johan Kero, Et Al.

Publications

The Hunga Tonga–Hunga Ha'apai volcano eruption was a unique event that caused many atmospheric phenomena around the globe. In this study, we investigate the atmospheric gravity waves in the mesosphere/lower thermosphere (MLT) launched by the volcanic explosion in the Pacific, leveraging multistatic meteor radar observations from the Chilean Observation Network De Meteor Radars (CONDOR) and the Nordic Meteor Radar Cluster in Fennoscandia. MLT winds are computed using a recently developed 3DVAR+DIV algorithm. We found eastward- and westward-traveling gravity waves in the CONDOR zonal and meridional wind measurements, which arrived 12 and 48 h after the eruption, and we found one …


Liouville Soliton Surfaces Obtained Using Darboux Transformations, S. C. Mancas, K. R. Acharya Apr 2023

Liouville Soliton Surfaces Obtained Using Darboux Transformations, S. C. Mancas, K. R. Acharya

Publications

We construct parametric Liouville surfaces corresponding to parametric soliton solutions of the Liouville equation and Darboux-transformed counterparts. We also use a modified variation of parameters method together with the elliptic functions method to obtain the traveling wave solutions to Liouville equation and express the centroaffine invariant in terms of the soliton Hamiltonian.


Accelerating Atmospheric Gravity Wave Simulations Using Machine Learning: Kelvin-Helmholtz Instability And Mountain Wave Sources Driving Gravity Wave Breaking And Secondary Gravity Wave Generation, Wenjun Dong, David Fritts, Alan Z. Liu, Hanli Liu, Jonathan Snively Apr 2023

Accelerating Atmospheric Gravity Wave Simulations Using Machine Learning: Kelvin-Helmholtz Instability And Mountain Wave Sources Driving Gravity Wave Breaking And Secondary Gravity Wave Generation, Wenjun Dong, David Fritts, Alan Z. Liu, Hanli Liu, Jonathan Snively

Publications

Gravity waves (GWs) and their associated multi-scale dynamics are known to play fundamental roles in energy and momentum transport and deposition processes throughout the atmosphere. We describe an initial, two-dimensional (2-D), machine learning model – the Compressible Atmosphere Model Network (CAMNet) - intended as a first step toward a more general, three-dimensional, highly-efficient, model for applications to nonlinear GW dynamics description. CAMNet employs a physics-informed neural operator to dramatically accelerate GW and secondary GW (SGW) simulations applied to two GW sources to date. CAMNet is trained on high-resolution simulations by the state-of-the-art model Complex Geometry Compressible Atmosphere Model (CGCAM). Two …