Atmospheric Sciences Commons^™

Deep Equatorial Pacific Ocean Oxygenation And Atmospheric Co2 Over The Last Ice Age, Franco Marcantonio, Ryan Hostak, Jennifer E. Hertzberg, Matthew W. Schmidt

OES Faculty Publications

Ventilation of carbon stored in the deep ocean is thought to play an important role in atmospheric CO₂ increases associated with Pleistocene deglaciations. The presence of this respired carbon has been recorded by an array of paleoceanographic proxies from various locations across the global ocean. Here we present a new sediment core from the Eastern Equatorial Pacific (EEP) Ocean spanning the last 180,000 years and reconstruct high-resolution 230Th-derived fluxes of 232Th and excess barium, along with redox-sensitive uranium concentrations to examine past variations in dust delivery, export productivity, and bottom-water oxygenation, respectively. Our bottom-water oxygenation record is compared to …

Assessing Agricultural Risk Management Using Historic Crop Insurance Loss Data Over The Ogallala Aquifer, Julian Reyes, Emile Elias, Erin M.K. Haacker, Amy Kremen, Lauren Parker, Caitlin Rottler

Department of Earth and Atmospheric Sciences: Faculty Publications

Much of the agricultural production in the Ogallala Aquifer region relies on groundwater for irrigation. In addition to declining water levels, weather and climate-driven events affect crop yields and revenues. Crop insurance serves as a risk management tool to mitigate these perils. Here, we seek to understand what long-term crop insurance loss data can tell us about agricultural risk management in the Ogallala. We assess patterns and trends in crop insurance loss data from the U.S. Department of Agriculture Risk Management Agency. Indemnities, or insurance payments, totaled $22 billion from 1989–2017 for the 161 counties that overlie the Ogallala Aquifer. …

An Analysis Of The Atmospheric Propagation Of Underground-Explosion-Generated Infrasonic Waves Based On The Equations Of Fluid Dynamics: Ground Recordings, Roberto Sabatini, Jonathan B. Snively, Michael P. Hickey, J. L. Garrison

Publications

An investigation on the propagation of underground-explosion-generated infrasonic waves is carried out via numerical simulations of the equations of fluid dynamics. More specifically, the continuity, momentum, and energy conservation equations are solved along with the Herzfeld-Rice equations in order to take into account the effects of vibrational relaxation phenomena. The radiation of acoustic energy by the ground motion caused by underground explosions is initiated by enforcing the equality, at ground level, between the component of the air velocity normal to the Earth's surface and the normal velocity of the ground layer. The velocity of the ground layer is defined semi-empirically …

Land Cover Change Detection In The Urban Catchments Of Dar Es Salaam, Tanzania Using Remote Sensing And Gis Techniques, Philip Mzava, Joel Nobert, Patrick Valimba

Tanzania Journal of Science

In this study, the Maximum Likelihood (ML) classification, Normalized Difference Vegetation Index (NDVI) and Artificial Neural Network (ANN) methods were applied to three (3) Landsat images collected over time (1979, 1998 and 2014), that contained historical land cover features for the urban catchments of Dar es Salaam. Five major land cover classes were identified, mapped, and the land cover changes investigated. The major land cover changes observed from post-classification comparisons of the classified images are: the forest land losing 17.09% of its area in the period 1979-1998 to other land covers, mainly turning to grassland, and from 1998 to 2014, …

The Role Of Multi-Charged Responses: Construction And Application Of A Tandem Differential Mobility Analyzer (Tdma), Christopher Ray Oxford

McKelvey School of Engineering Graduate Student Theses & Dissertations

Atmospheric aerosols impact health outcomes, visibility, and the energy balance of the earth. The atmosphere contains a variety of compounds, and the volatility (phase change enthalpy and vapor pressure) of each compound determines its partitioning between the gas phase and the particle phase. The hygroscopicity (an aerosol’s affinity for water) of an atmospheric aerosol particle is determined by the many compounds present in the particle, and thus, the volatility impacts hygroscopicity. Changes in hygroscopicity alter the fraction of the aerosol deposited in the lungs and the fraction of the aerosol activated into cloud droplets. Thus, understanding the volatility and hygroscopicity …

Integrated Species–Phenon Trees: Visualizing Infraspecific Diversity Within Lineages, Abdullah Khan Zehady, Barry G. Fordham, James G. Ogg

Purdue University Libraries Open Access Publishing Fund

The unprecedented detail with which contemporary molecular phylogenetics are visualizing infraspecific relationships within living species and species complexes cannot as yet be reliably extended into deep time. Yet paleontological systematics has routinely dealt in (mainly) morphotaxa envisaged in various ways to have been components of past species lineages. Bridging these perspectives can only enrich both. We present a visualization tool that digitally depicts infraspecific diversity within species through deep time. Our integrated species–phenon tree merges ancestor–descendant trees for fossil morphotaxa (phena) into reconstructed phylogenies of lineages (species) by expanding the latter into “species boxes” and placing the phenon trees inside. …

Steve And The Picket Fence: Evidence Of Feedback-Unstable Magnetosphere-Ionosphere Interaction, Evgeny Mishin, Anatoly Streltsov

Publications

This paper aims to extend the understanding of Strong Thermal Emission VelocityEnhancement (STEVE) and the Picket Fence related to strong subauroral ion drifts (SAID). Wenumerically demonstrated that precipitating energetic electrons are critical for the structuring of the PicketFence. It is created by feedback-unstable magnetosphere-ionosphere interactions driven by the SAIDelectric field when the Hall conductance created by energetic (≥1 keV) electrons exceeds the Pedersenconductance. We show that thermal excitation of the red-line emission in STEVE is inhibited by inelasticcollisions with molecular nitrogen. Suprathermal (≤500 eV) electrons coming from the turbulentplasmasphere appear to be the major source. We also show that the …

Determination Of Global Mean Eddy Diffusive Transport In The Mesosphere And Lower Thermosphere From Atomic Oxygen And Carbon Dioxide Climatologies, G. R. Swenson, C. C. J. H. Salinas, F. Vargas, Y. Zhu, M. Kaufmann, M. Jones Jr., A. Liu, Et Al.

Publications

Quantifying the eddy diffusion coefficient profile in the mesosphere and lower thermosphere (MLT) is critical to the constituent density distributions in the upper mesosphere and thermosphere. Previous work by Swenson et al. (2018, https://doi.org/10.1016/j.jastp.2018.05.014) estimated the global mean eddy diffusion (kzz) values in the upper mesosphere using atomic oxygen (O), derived from Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) hydroxyl (OH). In this study, vertical eddy diffusive transport velocities of O were determined from continuity of mass in the mesopause region (80–97 km), primarily via the HOx chemistry. Global average constituent climatology from previously deduced SABER ozone (O3) …

A Numerical Investigation On The Variation Of Sodium Ion And Observed Thermospheric Sodium Layer At Cerro Pachón, Chile During Equinox, Xuguang Cai, Tao Yuan, J. Vincent Eccles, N. M. Pedatella, Xiaoqi Xi, Chao Ban, Alan Z. Liu

Publications

The extension of the neutral sodium (Na) layer into the thermosphere (up to 170 km) has recently been observed at low and high latitudes using a Na lidar. However, the geophysical mechanisms and implications of its formation are currently unknown. In this study, we conduct an advanced two‐dimensional numerical simulation of the Na and Na+ variations in the E and F regions at low latitudes. The numerical simulations are used to investigate the contributions of the electromagnetic force, neutral wind, diffusion, and gravity. The simulations lead to three major findings. First, Na+ in the subtropical region of the geomagnetic equator …

Multilayer Observations And Modeling Of Thunderstorm-Generated Gravity Waves Over The Midwestern United States, C. J. Heale, J. B. Snively, A. N. Bhatt, L. Hoffmann, C. C. Stephan

Publications

We present multilayer observations and numerical simulations of gravity waves (GWs) generated by a series of Mesoscale Convective Systems over the midwestern United States. Strong semiconcentric GWs were observed and modeled, which couple from their tropospheric sources to the thermosphere, displaying strong nonlinearity indicated by instability, breaking, and formation of turbulent vortices. GWs in the stratosphere display a large range of horizontal scales from 34–400 km; however, the smaller wavelength waves break rapidly in the mesosphere and lower thermosphere. Larger-scale (≥150 km) waves dominate in the thermosphere and display northwestward propagation at 200–300 km altitude, opposing the mean winds. Despite …

Umphlett Qci Dec 2019, Natalie A. Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Soil Moisture Conditions

Agriculture

Energy

Infrastructure

Temperature

Precipitation

Long-Term Aerosol Trends And Variability Over Central Saudi Arabia Using Optical Characteristics From Solar Village Aeronet Measurements, Mohammed Al Otaibi, Ashraf Farahat, Bassam Tawabini, M. Hafidz Omar, Emad Ramadan, Abdelgadir Abuelgasim, Ramesh Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

Natural and anthropogenic aerosols over the Kingdom of Saudi Arabia (KSA) play a major role in affecting the regional radiation budget. The long-term variability of these aerosols’ physical and optical parameters, including aerosol optical depth (AOD) and Ångström exponent (α), were measured at a location near central KSA using the Solar Village (SV) AERONET (Aerosol Robotic Network) station during the period December 1999–January 2013. The AERONET measurements show an overall increase in AOD on an annual basis. This upward trend is mainly attributed to a prolonged increase in the monthly/seasonal mean AOD during March–June and during August– September. In contrast, …

Water Vapor Near-Uv Absorption: Laboratory Spectrum, Field Evidence, And Atmospheric Impacts, Linsen Pei, Qilong Min, Yuyi Du, Zhechen Wang, Bangsheng Yin, Kai Yang, Patrick Disterhoft, Thomas Pongetti, Lei Zhu

Environmental Health Sciences Faculty Scholarship

Absorption of solar radiation by water vapor in the near-UV region is a poorly-understood but important issue in atmospheric science. To better understand water vapor near-UV absorption, we constructed a cavity ring-down spectrometer with bandwidth of 5 cm^-1 (~0.05 nm) and obtained water vapor absorption cross-sections at 1 nm increments in the 290-350 nm region. Water vapor displays structured absorption over this range with maximum and minimum cross-sections of 8.4×10^-25 and 1.6×10^-25 cm²/molecule. Major water vapor absorption bands were observed at 293-295, 307-313, 319, 321-322, and 325 nm, with cross-section values higher than 4.0×10^{-25 …}

The Effect Of The 21 August 2017 Total Solar Eclipse On The Phase Of Vlf/Lf Signals, A. Rozhnoi, M. Solovieva, S. Shalimov, Dimitar Ouzounov, P. Gallagher, G. Verth, J. Mccauley, S. Shelyag, V. Fedun

Mathematics, Physics, and Computer Science Faculty Articles and Research

An experimental study of the phase and amplitude observations of sub‐ionospheric very low and low frequency (VLF/LF) signals is performed to analyze the response of the lower ionosphere during the 21 August 2017 total solar eclipse in the United States of America. Three different sub‐ionospheric wave paths are investigated. The length of the paths varies from 2,200 to 6,400 km, and the signal frequencies are 21.4, 25.2, and 40.75 kHz. The two paths cross the region of the total eclipse, and the third path is in the region of 40–60% of obscuration. None of the signals reveal any noticeable amplitude …

Lessons From The Ozone Hole, Carl P. Fictorie

Faculty Work Comprehensive List

"Good science works with evidence from creation, follows logically from that evidence, and avoids bias on the part of the scientist."

Posting about current environmental challenges from In All Things - an online journal for critical reflection on faith, culture, art, and every ordinary-yet-graced square inch of God’s creation.

https://inallthings.org/lessons-from-the-ozone-hole/

How Airport Construction Will Evolve With The Increased Effects Of Climate Change, Xavier M. Ashley

Beyond: Undergraduate Research Journal

This report addressed the effects rising global temperatures resulting from climate change have had on flight operations in their entirety. The research objective was to discover what methods could enhance climate adaptation in airport construction, as higher mean-surface temperatures have an increasingly negative effect on aircraft performance. The findings would primarily be of interest to the Federal Aviation Administration (FAA) Primary Office presiding over the planning and development of airports. Overall, the report provided a comprehensive analysis of global warming’s effects on aviation, including the implications of degraded aircraft performance and sea-level rise for coastal airports. Additionally, it examined comparative …

Gamma Ray Flashes Produced By Lightning Observed At Ground Level By Tetra-Ii, D. J. Pleshinger, S. T. Alnussirat, J. Arias, S. Bai, Y. Banadaki, M. L. Cherry, Anderson Sunda-Meya

Faculty and Staff Publications

In its first 2 years of operation, the ground-based Terrestrial gamma ray flash and Energetic Thunderstorm Rooftop Array (TETRA)-II array of gamma ray detectors has recorded 22 bursts of gamma rays of millisecond-scale duration associated with lightning. In this study, we present the TETRA-II observations detected at the three TETRA-II ground-level sites in Louisiana, Puerto Rico, and Panama together with the simultaneous radio frequency signals from the lightning data sets VAISALA Global Lightning Dataset, VAISALA National Lightning Detection Network, Earth Networks Total Lightning Network, andWorld Wide Lightning Location Network. The relative timing between the gamma ray events and the lightning …

Design And Performance Of A Communications System For A Low-Cost High Altitude Balloon Platform For Troposphere And Stratosphere Research, Noemí Miguélez Gómez

Doctoral Dissertations and Master's Theses

AFOSR Multidisciplinary University Research Initiative (MURI), "Integrated Measurement and Modeling Characterization of Stratospheric Turbulence", is a 5-year effort to resolve significant operational issues concerning hypersonic vehicle aerothermodynamics, boundary layer stability, and aero-optical propagation. In situ turbulence measurements along with modeling will quantify spatiotemporal statistics and the dependence of stratospheric turbulence on underlying meteorology to a degree not previously possible. Data from high altitude balloons sampling up to kHz is required to characterize turbulence to the inner-scale, or smaller, over paltitudes from 20 km to 35+ km.

This thesis presents the development of a standard balloon bus, based on reliable COTS …

Changes In Pm2.5 Peat Combustion Source Profiles With Atmospheric Aging In An Oxidation Flow Reactor, Judith C. Chow, Junji Cao, Lung-Wen Anthony Chen, Xiaoliang Wang, Qiyuan Wang, Jie Tian, Steven Sai Hang Ho, Adam C. Watts, Tessa B. Carlson, Steven D. Kohl, John G. Watson

Environmental & Global Health Faculty Research

Smoke from laboratory chamber burning of peat fuels from Russia, Siberia, the USA (Alaska and Florida), and Malaysia representing boreal, temperate, subtropical, and tropical regions was sampled before and after passing through a potential-aerosol-mass oxidation flow reactor (PAM-OFR) to simulate intermediately aged (∼2 d) and well-aged (∼7 d) source profiles. Species abundances in PM2.5 between aged and fresh profiles varied by several orders of magnitude with two distinguishable clusters, centered around 0.1 % for reactive and ionic species and centered around 10 % for carbon. Organic carbon (OC) accounted for 58 %–85 % of PM2.5 mass in fresh profiles with …

Aerosol Particle And Black Carbon Emission Factors Of Vehicular Fleet In Manila, Philippines, Leizel Madueño, Simonas Kecorius, Wolfram Birmili, Thomas Müller, James Bernard Simpas, Edgar Vallar, Maria Cecilia Galvez, Mylene Cayetano, Alfred Wiedensohler

Physics Faculty Publications

Poor air quality has been identified as one of the main risks to human health, especially in developing regions, where the information on physical chemical properties of air pollutants is lacking. To bridge this gap, we conducted an intensive measurement campaign in Manila, Philippines to determine the emission factors (EFs) of particle number (PN) and equivalent black carbon (BC). The focus was on public utility jeepneys (PUJ), equipped with old technology diesel engines, widely used for public transportation. The EFs were determined by aerosol physical measurements, fleet information, and modeled dilution using the Operational Street Pollution Model (OSPM). The results …